/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp

Bug Summary

File:	llvm/lib/Analysis/ScalarEvolution.cpp
Warning:	line 9494, column 41 Called C++ object pointer is null

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name ScalarEvolution.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -fno-split-dwarf-inlining -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-12/lib/clang/12.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/build-llvm/lib/Analysis -I /build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis -I /build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/build-llvm/include -I /build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-12/lib/clang/12.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/build-llvm/lib/Analysis -fdebug-prefix-map=/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -o /tmp/scan-build-2020-11-24-172238-38865-1 -x c++ /build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp

/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp

→

1//===- ScalarEvolution.cpp - Scalar Evolution Analysis --------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains the implementation of the scalar evolution analysis
10// engine, which is used primarily to analyze expressions involving induction
11// variables in loops.
12//
13// There are several aspects to this library.  First is the representation of
14// scalar expressions, which are represented as subclasses of the SCEV class.
15// These classes are used to represent certain types of subexpressions that we
16// can handle. We only create one SCEV of a particular shape, so
17// pointer-comparisons for equality are legal.
18//
19// One important aspect of the SCEV objects is that they are never cyclic, even
20// if there is a cycle in the dataflow for an expression (ie, a PHI node).  If
21// the PHI node is one of the idioms that we can represent (e.g., a polynomial
22// recurrence) then we represent it directly as a recurrence node, otherwise we
23// represent it as a SCEVUnknown node.
24//
25// In addition to being able to represent expressions of various types, we also
26// have folders that are used to build the *canonical* representation for a
27// particular expression.  These folders are capable of using a variety of
28// rewrite rules to simplify the expressions.
29//
30// Once the folders are defined, we can implement the more interesting
31// higher-level code, such as the code that recognizes PHI nodes of various
32// types, computes the execution count of a loop, etc.
33//
34// TODO: We should use these routines and value representations to implement
35// dependence analysis!
36//
37//===----------------------------------------------------------------------===//
38//
39// There are several good references for the techniques used in this analysis.
40//
41//  Chains of recurrences -- a method to expedite the evaluation
42//  of closed-form functions
43//  Olaf Bachmann, Paul S. Wang, Eugene V. Zima
44//
45//  On computational properties of chains of recurrences
46//  Eugene V. Zima
47//
48//  Symbolic Evaluation of Chains of Recurrences for Loop Optimization
49//  Robert A. van Engelen
50//
51//  Efficient Symbolic Analysis for Optimizing Compilers
52//  Robert A. van Engelen
53//
54//  Using the chains of recurrences algebra for data dependence testing and
55//  induction variable substitution
56//  MS Thesis, Johnie Birch
57//
58//===----------------------------------------------------------------------===//

60#include "llvm/Analysis/ScalarEvolution.h"
61#include "llvm/ADT/APInt.h"
62#include "llvm/ADT/ArrayRef.h"
63#include "llvm/ADT/DenseMap.h"
64#include "llvm/ADT/DepthFirstIterator.h"
65#include "llvm/ADT/EquivalenceClasses.h"
66#include "llvm/ADT/FoldingSet.h"
67#include "llvm/ADT/None.h"
68#include "llvm/ADT/Optional.h"
69#include "llvm/ADT/STLExtras.h"
70#include "llvm/ADT/ScopeExit.h"
71#include "llvm/ADT/Sequence.h"
72#include "llvm/ADT/SetVector.h"
73#include "llvm/ADT/SmallPtrSet.h"
74#include "llvm/ADT/SmallSet.h"
75#include "llvm/ADT/SmallVector.h"
76#include "llvm/ADT/Statistic.h"
77#include "llvm/ADT/StringRef.h"
78#include "llvm/Analysis/AssumptionCache.h"
79#include "llvm/Analysis/ConstantFolding.h"
80#include "llvm/Analysis/InstructionSimplify.h"
81#include "llvm/Analysis/LoopInfo.h"
82#include "llvm/Analysis/ScalarEvolutionDivision.h"
83#include "llvm/Analysis/ScalarEvolutionExpressions.h"
84#include "llvm/Analysis/TargetLibraryInfo.h"
85#include "llvm/Analysis/ValueTracking.h"
86#include "llvm/Config/llvm-config.h"
87#include "llvm/IR/Argument.h"
88#include "llvm/IR/BasicBlock.h"
89#include "llvm/IR/CFG.h"
90#include "llvm/IR/Constant.h"
91#include "llvm/IR/ConstantRange.h"
92#include "llvm/IR/Constants.h"
93#include "llvm/IR/DataLayout.h"
94#include "llvm/IR/DerivedTypes.h"
95#include "llvm/IR/Dominators.h"
96#include "llvm/IR/Function.h"
97#include "llvm/IR/GlobalAlias.h"
98#include "llvm/IR/GlobalValue.h"
99#include "llvm/IR/GlobalVariable.h"
100#include "llvm/IR/InstIterator.h"
101#include "llvm/IR/InstrTypes.h"
102#include "llvm/IR/Instruction.h"
103#include "llvm/IR/Instructions.h"
104#include "llvm/IR/IntrinsicInst.h"
105#include "llvm/IR/Intrinsics.h"
106#include "llvm/IR/LLVMContext.h"
107#include "llvm/IR/Metadata.h"
108#include "llvm/IR/Operator.h"
109#include "llvm/IR/PatternMatch.h"
110#include "llvm/IR/Type.h"
111#include "llvm/IR/Use.h"
112#include "llvm/IR/User.h"
113#include "llvm/IR/Value.h"
114#include "llvm/IR/Verifier.h"
115#include "llvm/InitializePasses.h"
116#include "llvm/Pass.h"
117#include "llvm/Support/Casting.h"
118#include "llvm/Support/CommandLine.h"
119#include "llvm/Support/Compiler.h"
120#include "llvm/Support/Debug.h"
121#include "llvm/Support/ErrorHandling.h"
122#include "llvm/Support/KnownBits.h"
123#include "llvm/Support/SaveAndRestore.h"
124#include "llvm/Support/raw_ostream.h"
125#include <algorithm>
126#include <cassert>
127#include <climits>
128#include <cstddef>
129#include <cstdint>
130#include <cstdlib>
131#include <map>
132#include <memory>
133#include <tuple>
134#include <utility>
135#include <vector>

137using namespace llvm;

139#define DEBUG_TYPE"scalar-evolution" "scalar-evolution"

141STATISTIC(NumArrayLenItCounts,static llvm::Statistic NumArrayLenItCounts = {"scalar-evolution"
, "NumArrayLenItCounts", "Number of trip counts computed with array length"
}
        "Number of trip counts computed with array length")static llvm::Statistic NumArrayLenItCounts = {"scalar-evolution"
, "NumArrayLenItCounts", "Number of trip counts computed with array length"
};
143STATISTIC(NumTripCountsComputed,static llvm::Statistic NumTripCountsComputed = {"scalar-evolution"
, "NumTripCountsComputed", "Number of loops with predictable loop counts"
}
        "Number of loops with predictable loop counts")static llvm::Statistic NumTripCountsComputed = {"scalar-evolution"
, "NumTripCountsComputed", "Number of loops with predictable loop counts"
};
145STATISTIC(NumTripCountsNotComputed,static llvm::Statistic NumTripCountsNotComputed = {"scalar-evolution"
, "NumTripCountsNotComputed", "Number of loops without predictable loop counts"
}
        "Number of loops without predictable loop counts")static llvm::Statistic NumTripCountsNotComputed = {"scalar-evolution"
, "NumTripCountsNotComputed", "Number of loops without predictable loop counts"
};
147STATISTIC(NumBruteForceTripCountsComputed,static llvm::Statistic NumBruteForceTripCountsComputed = {"scalar-evolution"
, "NumBruteForceTripCountsComputed", "Number of loops with trip counts computed by force"
}
        "Number of loops with trip counts computed by force")static llvm::Statistic NumBruteForceTripCountsComputed = {"scalar-evolution"
, "NumBruteForceTripCountsComputed", "Number of loops with trip counts computed by force"
};

150static cl::opt<unsigned>
151MaxBruteForceIterations("scalar-evolution-max-iterations", cl::ReallyHidden,
                      cl::ZeroOrMore,
                      cl::desc("Maximum number of iterations SCEV will "
                               "symbolically execute a constant "
                               "derived loop"),
                      cl::init(100));

158// FIXME: Enable this with EXPENSIVE_CHECKS when the test suite is clean.
159static cl::opt<bool> VerifySCEV(
  "verify-scev", cl::Hidden,
  cl::desc("Verify ScalarEvolution's backedge taken counts (slow)"));
162static cl::opt<bool> VerifySCEVStrict(
  "verify-scev-strict", cl::Hidden,
  cl::desc("Enable stricter verification with -verify-scev is passed"));
165static cl::opt<bool>
  VerifySCEVMap("verify-scev-maps", cl::Hidden,
                cl::desc("Verify no dangling value in ScalarEvolution's "
                         "ExprValueMap (slow)"));

170static cl::opt<bool> VerifyIR(
  "scev-verify-ir", cl::Hidden,
  cl::desc("Verify IR correctness when making sensitive SCEV queries (slow)"),
  cl::init(false));

175static cl::opt<unsigned> MulOpsInlineThreshold(
  "scev-mulops-inline-threshold", cl::Hidden,
  cl::desc("Threshold for inlining multiplication operands into a SCEV"),
  cl::init(32));

180static cl::opt<unsigned> AddOpsInlineThreshold(
  "scev-addops-inline-threshold", cl::Hidden,
  cl::desc("Threshold for inlining addition operands into a SCEV"),
  cl::init(500));

185static cl::opt<unsigned> MaxSCEVCompareDepth(
  "scalar-evolution-max-scev-compare-depth", cl::Hidden,
  cl::desc("Maximum depth of recursive SCEV complexity comparisons"),
  cl::init(32));

190static cl::opt<unsigned> MaxSCEVOperationsImplicationDepth(
  "scalar-evolution-max-scev-operations-implication-depth", cl::Hidden,
  cl::desc("Maximum depth of recursive SCEV operations implication analysis"),
  cl::init(2));

195static cl::opt<unsigned> MaxValueCompareDepth(
  "scalar-evolution-max-value-compare-depth", cl::Hidden,
  cl::desc("Maximum depth of recursive value complexity comparisons"),
  cl::init(2));

200static cl::opt<unsigned>
  MaxArithDepth("scalar-evolution-max-arith-depth", cl::Hidden,
                cl::desc("Maximum depth of recursive arithmetics"),
                cl::init(32));

205static cl::opt<unsigned> MaxConstantEvolvingDepth(
  "scalar-evolution-max-constant-evolving-depth", cl::Hidden,
  cl::desc("Maximum depth of recursive constant evolving"), cl::init(32));

209static cl::opt<unsigned>
  MaxCastDepth("scalar-evolution-max-cast-depth", cl::Hidden,
               cl::desc("Maximum depth of recursive SExt/ZExt/Trunc"),
               cl::init(8));

214static cl::opt<unsigned>
  MaxAddRecSize("scalar-evolution-max-add-rec-size", cl::Hidden,
                cl::desc("Max coefficients in AddRec during evolving"),
                cl::init(8));

219static cl::opt<unsigned>
  HugeExprThreshold("scalar-evolution-huge-expr-threshold", cl::Hidden,
                cl::desc("Size of the expression which is considered huge"),
                cl::init(4096));

224static cl::opt<bool>
225ClassifyExpressions("scalar-evolution-classify-expressions",
  cl::Hidden, cl::init(true),
  cl::desc("When printing analysis, include information on every instruction"));

229static cl::opt<bool> UseExpensiveRangeSharpening(
  "scalar-evolution-use-expensive-range-sharpening", cl::Hidden,
  cl::init(false),
  cl::desc("Use more powerful methods of sharpening expression ranges. May "
           "be costly in terms of compile time"));

235//===----------------------------------------------------------------------===//
236//                           SCEV class definitions
237//===----------------------------------------------------------------------===//

239//===----------------------------------------------------------------------===//
240// Implementation of the SCEV class.
241//

243#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
244LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void SCEV::dump() const {
print(dbgs());
dbgs() << '\n';
247}
248#endif

250void SCEV::print(raw_ostream &OS) const {
switch (getSCEVType()) {
case scConstant:
  cast<SCEVConstant>(this)->getValue()->printAsOperand(OS, false);
  return;
case scPtrToInt: {
  const SCEVPtrToIntExpr *PtrToInt = cast<SCEVPtrToIntExpr>(this);
  const SCEV *Op = PtrToInt->getOperand();
  OS << "(ptrtoint " << *Op->getType() << " " << *Op << " to "
     << *PtrToInt->getType() << ")";
  return;
}
case scTruncate: {
  const SCEVTruncateExpr *Trunc = cast<SCEVTruncateExpr>(this);
  const SCEV *Op = Trunc->getOperand();
  OS << "(trunc " << *Op->getType() << " " << *Op << " to "
     << *Trunc->getType() << ")";
  return;
}
case scZeroExtend: {
  const SCEVZeroExtendExpr *ZExt = cast<SCEVZeroExtendExpr>(this);
  const SCEV *Op = ZExt->getOperand();
  OS << "(zext " << *Op->getType() << " " << *Op << " to "
     << *ZExt->getType() << ")";
  return;
}
case scSignExtend: {
  const SCEVSignExtendExpr *SExt = cast<SCEVSignExtendExpr>(this);
  const SCEV *Op = SExt->getOperand();
  OS << "(sext " << *Op->getType() << " " << *Op << " to "
     << *SExt->getType() << ")";
  return;
}
case scAddRecExpr: {
  const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(this);
  OS << "{" << *AR->getOperand(0);
  for (unsigned i = 1, e = AR->getNumOperands(); i != e; ++i)
    OS << ",+," << *AR->getOperand(i);
  OS << "}<";
  if (AR->hasNoUnsignedWrap())
    OS << "nuw><";
  if (AR->hasNoSignedWrap())
    OS << "nsw><";
  if (AR->hasNoSelfWrap() &&
      !AR->getNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW)))
    OS << "nw><";
  AR->getLoop()->getHeader()->printAsOperand(OS, /*PrintType=*/false);
  OS << ">";
  return;
}
case scAddExpr:
case scMulExpr:
case scUMaxExpr:
case scSMaxExpr:
case scUMinExpr:
case scSMinExpr: {
  const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(this);
  const char *OpStr = nullptr;
  switch (NAry->getSCEVType()) {
  case scAddExpr: OpStr = " + "; break;
  case scMulExpr: OpStr = " * "; break;
  case scUMaxExpr: OpStr = " umax "; break;
  case scSMaxExpr: OpStr = " smax "; break;
  case scUMinExpr:
    OpStr = " umin ";
    break;
  case scSMinExpr:
    OpStr = " smin ";
    break;
  default:
    llvm_unreachable("There are no other nary expression types.")::llvm::llvm_unreachable_internal("There are no other nary expression types."
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 320);
  }
  OS << "(";
  for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), E = NAry->op_end();
       I != E; ++I) {
    OS << **I;
    if (std::next(I) != E)
      OS << OpStr;
  }
  OS << ")";
  switch (NAry->getSCEVType()) {
  case scAddExpr:
  case scMulExpr:
    if (NAry->hasNoUnsignedWrap())
      OS << "<nuw>";
    if (NAry->hasNoSignedWrap())
      OS << "<nsw>";
    break;
  default:
    // Nothing to print for other nary expressions.
    break;
  }
  return;
}
case scUDivExpr: {
  const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(this);
  OS << "(" << *UDiv->getLHS() << " /u " << *UDiv->getRHS() << ")";
  return;
}
case scUnknown: {
  const SCEVUnknown *U = cast<SCEVUnknown>(this);
  Type *AllocTy;
  if (U->isSizeOf(AllocTy)) {
    OS << "sizeof(" << *AllocTy << ")";
    return;
  }
  if (U->isAlignOf(AllocTy)) {
    OS << "alignof(" << *AllocTy << ")";
    return;
  }

  Type *CTy;
  Constant *FieldNo;
  if (U->isOffsetOf(CTy, FieldNo)) {
    OS << "offsetof(" << *CTy << ", ";
    FieldNo->printAsOperand(OS, false);
    OS << ")";
    return;
  }

  // Otherwise just print it normally.
  U->getValue()->printAsOperand(OS, false);
  return;
}
case scCouldNotCompute:
  OS << "***COULDNOTCOMPUTE***";
  return;
}
llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 378);
379}

381Type *SCEV::getType() const {
switch (getSCEVType()) {
case scConstant:
  return cast<SCEVConstant>(this)->getType();
case scPtrToInt:
case scTruncate:
case scZeroExtend:
case scSignExtend:
  return cast<SCEVCastExpr>(this)->getType();
case scAddRecExpr:
case scMulExpr:
case scUMaxExpr:
case scSMaxExpr:
case scUMinExpr:
case scSMinExpr:
  return cast<SCEVNAryExpr>(this)->getType();
case scAddExpr:
  return cast<SCEVAddExpr>(this)->getType();
case scUDivExpr:
  return cast<SCEVUDivExpr>(this)->getType();
case scUnknown:
  return cast<SCEVUnknown>(this)->getType();
case scCouldNotCompute:
  llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 404);
}
llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 406);
407}

409bool SCEV::isZero() const {
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this))
  return SC->getValue()->isZero();
return false;
413}

415bool SCEV::isOne() const {
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this))
  return SC->getValue()->isOne();
return false;
419}

421bool SCEV::isAllOnesValue() const {
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this))
  return SC->getValue()->isMinusOne();
return false;
425}

427bool SCEV::isNonConstantNegative() const {
const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(this);
if (!Mul) return false;

// If there is a constant factor, it will be first.
const SCEVConstant *SC = dyn_cast<SCEVConstant>(Mul->getOperand(0));
if (!SC) return false;

// Return true if the value is negative, this matches things like (-42 * V).
return SC->getAPInt().isNegative();
437}

439SCEVCouldNotCompute::SCEVCouldNotCompute() :
SCEV(FoldingSetNodeIDRef(), scCouldNotCompute, 0) {}

442bool SCEVCouldNotCompute::classof(const SCEV *S) {
return S->getSCEVType() == scCouldNotCompute;
444}

446const SCEV *ScalarEvolution::getConstant(ConstantInt *V) {
FoldingSetNodeID ID;
ID.AddInteger(scConstant);
ID.AddPointer(V);
void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
SCEV *S = new (SCEVAllocator) SCEVConstant(ID.Intern(SCEVAllocator), V);
UniqueSCEVs.InsertNode(S, IP);
return S;
455}

457const SCEV *ScalarEvolution::getConstant(const APInt &Val) {
return getConstant(ConstantInt::get(getContext(), Val));
459}

461const SCEV *
462ScalarEvolution::getConstant(Type *Ty, uint64_t V, bool isSigned) {
IntegerType *ITy = cast<IntegerType>(getEffectiveSCEVType(Ty));
return getConstant(ConstantInt::get(ITy, V, isSigned));
465}

467SCEVCastExpr::SCEVCastExpr(const FoldingSetNodeIDRef ID, SCEVTypes SCEVTy,
                         const SCEV *op, Type *ty)
  : SCEV(ID, SCEVTy, computeExpressionSize(op)), Ty(ty) {
Operands[0] = op;
471}

473SCEVPtrToIntExpr::SCEVPtrToIntExpr(const FoldingSetNodeIDRef ID, const SCEV *Op,
                                 Type *ITy)
  : SCEVCastExpr(ID, scPtrToInt, Op, ITy) {
assert(getOperand()->getType()->isPointerTy() && Ty->isIntegerTy() &&((getOperand()->getType()->isPointerTy() && Ty->
isIntegerTy() && "Must be a non-bit-width-changing pointer-to-integer cast!"
) ? static_cast<void> (0) : __assert_fail ("getOperand()->getType()->isPointerTy() && Ty->isIntegerTy() && \"Must be a non-bit-width-changing pointer-to-integer cast!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 477, __PRETTY_FUNCTION__))
       "Must be a non-bit-width-changing pointer-to-integer cast!")((getOperand()->getType()->isPointerTy() && Ty->
isIntegerTy() && "Must be a non-bit-width-changing pointer-to-integer cast!"
) ? static_cast<void> (0) : __assert_fail ("getOperand()->getType()->isPointerTy() && Ty->isIntegerTy() && \"Must be a non-bit-width-changing pointer-to-integer cast!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 477, __PRETTY_FUNCTION__));
478}

480SCEVIntegralCastExpr::SCEVIntegralCastExpr(const FoldingSetNodeIDRef ID,
                                         SCEVTypes SCEVTy, const SCEV *op,
                                         Type *ty)
  : SCEVCastExpr(ID, SCEVTy, op, ty) {}

485SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeIDRef ID, const SCEV *op,
                                 Type *ty)
  : SCEVIntegralCastExpr(ID, scTruncate, op, ty) {
assert(getOperand()->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((getOperand()->getType()->isIntOrPtrTy() && Ty
->isIntOrPtrTy() && "Cannot truncate non-integer value!"
) ? static_cast<void> (0) : __assert_fail ("getOperand()->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate non-integer value!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 489, __PRETTY_FUNCTION__))
       "Cannot truncate non-integer value!")((getOperand()->getType()->isIntOrPtrTy() && Ty
->isIntOrPtrTy() && "Cannot truncate non-integer value!"
) ? static_cast<void> (0) : __assert_fail ("getOperand()->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate non-integer value!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 489, __PRETTY_FUNCTION__));
490}

492SCEVZeroExtendExpr::SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID,
                                     const SCEV *op, Type *ty)
  : SCEVIntegralCastExpr(ID, scZeroExtend, op, ty) {
assert(getOperand()->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((getOperand()->getType()->isIntOrPtrTy() && Ty
->isIntOrPtrTy() && "Cannot zero extend non-integer value!"
) ? static_cast<void> (0) : __assert_fail ("getOperand()->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot zero extend non-integer value!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 496, __PRETTY_FUNCTION__))
       "Cannot zero extend non-integer value!")((getOperand()->getType()->isIntOrPtrTy() && Ty
->isIntOrPtrTy() && "Cannot zero extend non-integer value!"
) ? static_cast<void> (0) : __assert_fail ("getOperand()->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot zero extend non-integer value!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 496, __PRETTY_FUNCTION__));
497}

499SCEVSignExtendExpr::SCEVSignExtendExpr(const FoldingSetNodeIDRef ID,
                                     const SCEV *op, Type *ty)
  : SCEVIntegralCastExpr(ID, scSignExtend, op, ty) {
assert(getOperand()->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((getOperand()->getType()->isIntOrPtrTy() && Ty
->isIntOrPtrTy() && "Cannot sign extend non-integer value!"
) ? static_cast<void> (0) : __assert_fail ("getOperand()->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot sign extend non-integer value!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 503, __PRETTY_FUNCTION__))
       "Cannot sign extend non-integer value!")((getOperand()->getType()->isIntOrPtrTy() && Ty
->isIntOrPtrTy() && "Cannot sign extend non-integer value!"
) ? static_cast<void> (0) : __assert_fail ("getOperand()->getType()->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot sign extend non-integer value!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 503, __PRETTY_FUNCTION__));
504}

506void SCEVUnknown::deleted() {
// Clear this SCEVUnknown from various maps.
SE->forgetMemoizedResults(this);

// Remove this SCEVUnknown from the uniquing map.
SE->UniqueSCEVs.RemoveNode(this);

// Release the value.
setValPtr(nullptr);
515}

517void SCEVUnknown::allUsesReplacedWith(Value *New) {
// Remove this SCEVUnknown from the uniquing map.
SE->UniqueSCEVs.RemoveNode(this);

// Update this SCEVUnknown to point to the new value. This is needed
// because there may still be outstanding SCEVs which still point to
// this SCEVUnknown.
setValPtr(New);
525}

527bool SCEVUnknown::isSizeOf(Type *&AllocTy) const {
if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue()))
  if (VCE->getOpcode() == Instruction::PtrToInt)
    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
      if (CE->getOpcode() == Instruction::GetElementPtr &&
          CE->getOperand(0)->isNullValue() &&
          CE->getNumOperands() == 2)
        if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(1)))
          if (CI->isOne()) {
            AllocTy = cast<PointerType>(CE->getOperand(0)->getType())
                               ->getElementType();
            return true;
          }

return false;
542}

544bool SCEVUnknown::isAlignOf(Type *&AllocTy) const {
if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue()))
  if (VCE->getOpcode() == Instruction::PtrToInt)
    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
      if (CE->getOpcode() == Instruction::GetElementPtr &&
          CE->getOperand(0)->isNullValue()) {
        Type *Ty =
          cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
        if (StructType *STy = dyn_cast<StructType>(Ty))
          if (!STy->isPacked() &&
              CE->getNumOperands() == 3 &&
              CE->getOperand(1)->isNullValue()) {
            if (ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(2)))
              if (CI->isOne() &&
                  STy->getNumElements() == 2 &&
                  STy->getElementType(0)->isIntegerTy(1)) {
                AllocTy = STy->getElementType(1);
                return true;
              }
          }
      }

return false;
567}

569bool SCEVUnknown::isOffsetOf(Type *&CTy, Constant *&FieldNo) const {
if (ConstantExpr *VCE = dyn_cast<ConstantExpr>(getValue()))
  if (VCE->getOpcode() == Instruction::PtrToInt)
    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(VCE->getOperand(0)))
      if (CE->getOpcode() == Instruction::GetElementPtr &&
          CE->getNumOperands() == 3 &&
          CE->getOperand(0)->isNullValue() &&
          CE->getOperand(1)->isNullValue()) {
        Type *Ty =
          cast<PointerType>(CE->getOperand(0)->getType())->getElementType();
        // Ignore vector types here so that ScalarEvolutionExpander doesn't
        // emit getelementptrs that index into vectors.
        if (Ty->isStructTy() || Ty->isArrayTy()) {
          CTy = Ty;
          FieldNo = CE->getOperand(2);
          return true;
        }
      }

return false;
589}

591//===----------------------------------------------------------------------===//
592//                               SCEV Utilities
593//===----------------------------------------------------------------------===//

595/// Compare the two values \p LV and \p RV in terms of their "complexity" where
596/// "complexity" is a partial (and somewhat ad-hoc) relation used to order
597/// operands in SCEV expressions.  \p EqCache is a set of pairs of values that
598/// have been previously deemed to be "equally complex" by this routine.  It is
599/// intended to avoid exponential time complexity in cases like:
600///
601///   %a = f(%x, %y)
602///   %b = f(%a, %a)
603///   %c = f(%b, %b)
604///
605///   %d = f(%x, %y)
606///   %e = f(%d, %d)
607///   %f = f(%e, %e)
608///
609///   CompareValueComplexity(%f, %c)
610///
611/// Since we do not continue running this routine on expression trees once we
612/// have seen unequal values, there is no need to track them in the cache.
613static int
614CompareValueComplexity(EquivalenceClasses<const Value *> &EqCacheValue,
                     const LoopInfo *const LI, Value *LV, Value *RV,
                     unsigned Depth) {
if (Depth > MaxValueCompareDepth || EqCacheValue.isEquivalent(LV, RV))
  return 0;

// Order pointer values after integer values. This helps SCEVExpander form
// GEPs.
bool LIsPointer = LV->getType()->isPointerTy(),
     RIsPointer = RV->getType()->isPointerTy();
if (LIsPointer != RIsPointer)
  return (int)LIsPointer - (int)RIsPointer;

// Compare getValueID values.
unsigned LID = LV->getValueID(), RID = RV->getValueID();
if (LID != RID)
  return (int)LID - (int)RID;

// Sort arguments by their position.
if (const auto *LA = dyn_cast<Argument>(LV)) {
  const auto *RA = cast<Argument>(RV);
  unsigned LArgNo = LA->getArgNo(), RArgNo = RA->getArgNo();
  return (int)LArgNo - (int)RArgNo;
}

if (const auto *LGV = dyn_cast<GlobalValue>(LV)) {
  const auto *RGV = cast<GlobalValue>(RV);

  const auto IsGVNameSemantic = [&](const GlobalValue *GV) {
    auto LT = GV->getLinkage();
    return !(GlobalValue::isPrivateLinkage(LT) ||
             GlobalValue::isInternalLinkage(LT));
  };

  // Use the names to distinguish the two values, but only if the
  // names are semantically important.
  if (IsGVNameSemantic(LGV) && IsGVNameSemantic(RGV))
    return LGV->getName().compare(RGV->getName());
}

// For instructions, compare their loop depth, and their operand count.  This
// is pretty loose.
if (const auto *LInst = dyn_cast<Instruction>(LV)) {
  const auto *RInst = cast<Instruction>(RV);

  // Compare loop depths.
  const BasicBlock *LParent = LInst->getParent(),
                   *RParent = RInst->getParent();
  if (LParent != RParent) {
    unsigned LDepth = LI->getLoopDepth(LParent),
             RDepth = LI->getLoopDepth(RParent);
    if (LDepth != RDepth)
      return (int)LDepth - (int)RDepth;
  }

  // Compare the number of operands.
  unsigned LNumOps = LInst->getNumOperands(),
           RNumOps = RInst->getNumOperands();
  if (LNumOps != RNumOps)
    return (int)LNumOps - (int)RNumOps;

  for (unsigned Idx : seq(0u, LNumOps)) {
    int Result =
        CompareValueComplexity(EqCacheValue, LI, LInst->getOperand(Idx),
                               RInst->getOperand(Idx), Depth + 1);
    if (Result != 0)
      return Result;
  }
}

EqCacheValue.unionSets(LV, RV);
return 0;
686}

688// Return negative, zero, or positive, if LHS is less than, equal to, or greater
689// than RHS, respectively. A three-way result allows recursive comparisons to be
690// more efficient.
691static int CompareSCEVComplexity(
  EquivalenceClasses<const SCEV *> &EqCacheSCEV,
  EquivalenceClasses<const Value *> &EqCacheValue,
  const LoopInfo *const LI, const SCEV *LHS, const SCEV *RHS,
  DominatorTree &DT, unsigned Depth = 0) {
// Fast-path: SCEVs are uniqued so we can do a quick equality check.
if (LHS == RHS)
  return 0;

// Primarily, sort the SCEVs by their getSCEVType().
SCEVTypes LType = LHS->getSCEVType(), RType = RHS->getSCEVType();
if (LType != RType)
  return (int)LType - (int)RType;

if (Depth > MaxSCEVCompareDepth || EqCacheSCEV.isEquivalent(LHS, RHS))
  return 0;
// Aside from the getSCEVType() ordering, the particular ordering
// isn't very important except that it's beneficial to be consistent,
// so that (a + b) and (b + a) don't end up as different expressions.
switch (LType) {
case scUnknown: {
  const SCEVUnknown *LU = cast<SCEVUnknown>(LHS);
  const SCEVUnknown *RU = cast<SCEVUnknown>(RHS);

  int X = CompareValueComplexity(EqCacheValue, LI, LU->getValue(),
                                 RU->getValue(), Depth + 1);
  if (X == 0)
    EqCacheSCEV.unionSets(LHS, RHS);
  return X;
}

case scConstant: {
  const SCEVConstant *LC = cast<SCEVConstant>(LHS);
  const SCEVConstant *RC = cast<SCEVConstant>(RHS);

  // Compare constant values.
  const APInt &LA = LC->getAPInt();
  const APInt &RA = RC->getAPInt();
  unsigned LBitWidth = LA.getBitWidth(), RBitWidth = RA.getBitWidth();
  if (LBitWidth != RBitWidth)
    return (int)LBitWidth - (int)RBitWidth;
  return LA.ult(RA) ? -1 : 1;
}

case scAddRecExpr: {
  const SCEVAddRecExpr *LA = cast<SCEVAddRecExpr>(LHS);
  const SCEVAddRecExpr *RA = cast<SCEVAddRecExpr>(RHS);

  // There is always a dominance between two recs that are used by one SCEV,
  // so we can safely sort recs by loop header dominance. We require such
  // order in getAddExpr.
  const Loop *LLoop = LA->getLoop(), *RLoop = RA->getLoop();
  if (LLoop != RLoop) {
    const BasicBlock *LHead = LLoop->getHeader(), *RHead = RLoop->getHeader();
    assert(LHead != RHead && "Two loops share the same header?")((LHead != RHead && "Two loops share the same header?"
) ? static_cast<void> (0) : __assert_fail ("LHead != RHead && \"Two loops share the same header?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 745, __PRETTY_FUNCTION__));
    if (DT.dominates(LHead, RHead))
      return 1;
    else
      assert(DT.dominates(RHead, LHead) &&((DT.dominates(RHead, LHead) && "No dominance between recurrences used by one SCEV?"
) ? static_cast<void> (0) : __assert_fail ("DT.dominates(RHead, LHead) && \"No dominance between recurrences used by one SCEV?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 750, __PRETTY_FUNCTION__))
             "No dominance between recurrences used by one SCEV?")((DT.dominates(RHead, LHead) && "No dominance between recurrences used by one SCEV?"
) ? static_cast<void> (0) : __assert_fail ("DT.dominates(RHead, LHead) && \"No dominance between recurrences used by one SCEV?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 750, __PRETTY_FUNCTION__));
    return -1;
  }

  // Addrec complexity grows with operand count.
  unsigned LNumOps = LA->getNumOperands(), RNumOps = RA->getNumOperands();
  if (LNumOps != RNumOps)
    return (int)LNumOps - (int)RNumOps;

  // Lexicographically compare.
  for (unsigned i = 0; i != LNumOps; ++i) {
    int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI,
                                  LA->getOperand(i), RA->getOperand(i), DT,
                                  Depth + 1);
    if (X != 0)
      return X;
  }
  EqCacheSCEV.unionSets(LHS, RHS);
  return 0;
}

case scAddExpr:
case scMulExpr:
case scSMaxExpr:
case scUMaxExpr:
case scSMinExpr:
case scUMinExpr: {
  const SCEVNAryExpr *LC = cast<SCEVNAryExpr>(LHS);
  const SCEVNAryExpr *RC = cast<SCEVNAryExpr>(RHS);

  // Lexicographically compare n-ary expressions.
  unsigned LNumOps = LC->getNumOperands(), RNumOps = RC->getNumOperands();
  if (LNumOps != RNumOps)
    return (int)LNumOps - (int)RNumOps;

  for (unsigned i = 0; i != LNumOps; ++i) {
    int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI,
                                  LC->getOperand(i), RC->getOperand(i), DT,
                                  Depth + 1);
    if (X != 0)
      return X;
  }
  EqCacheSCEV.unionSets(LHS, RHS);
  return 0;
}

case scUDivExpr: {
  const SCEVUDivExpr *LC = cast<SCEVUDivExpr>(LHS);
  const SCEVUDivExpr *RC = cast<SCEVUDivExpr>(RHS);

  // Lexicographically compare udiv expressions.
  int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LC->getLHS(),
                                RC->getLHS(), DT, Depth + 1);
  if (X != 0)
    return X;
  X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LC->getRHS(),
                            RC->getRHS(), DT, Depth + 1);
  if (X == 0)
    EqCacheSCEV.unionSets(LHS, RHS);
  return X;
}

case scPtrToInt:
case scTruncate:
case scZeroExtend:
case scSignExtend: {
  const SCEVCastExpr *LC = cast<SCEVCastExpr>(LHS);
  const SCEVCastExpr *RC = cast<SCEVCastExpr>(RHS);

  // Compare cast expressions by operand.
  int X = CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI,
                                LC->getOperand(), RC->getOperand(), DT,
                                Depth + 1);
  if (X == 0)
    EqCacheSCEV.unionSets(LHS, RHS);
  return X;
}

case scCouldNotCompute:
  llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 829);
}
llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 831);
832}

834/// Given a list of SCEV objects, order them by their complexity, and group
835/// objects of the same complexity together by value.  When this routine is
836/// finished, we know that any duplicates in the vector are consecutive and that
837/// complexity is monotonically increasing.
838///
839/// Note that we go take special precautions to ensure that we get deterministic
840/// results from this routine.  In other words, we don't want the results of
841/// this to depend on where the addresses of various SCEV objects happened to
842/// land in memory.
843static void GroupByComplexity(SmallVectorImpl<const SCEV *> &Ops,
                            LoopInfo *LI, DominatorTree &DT) {
if (Ops.size() < 2) return;  // Noop

EquivalenceClasses<const SCEV *> EqCacheSCEV;
EquivalenceClasses<const Value *> EqCacheValue;
if (Ops.size() == 2) {
  // This is the common case, which also happens to be trivially simple.
  // Special case it.
  const SCEV *&LHS = Ops[0], *&RHS = Ops[1];
  if (CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, RHS, LHS, DT) < 0)
    std::swap(LHS, RHS);
  return;
}

// Do the rough sort by complexity.
llvm::stable_sort(Ops, [&](const SCEV *LHS, const SCEV *RHS) {
  return CompareSCEVComplexity(EqCacheSCEV, EqCacheValue, LI, LHS, RHS, DT) <
         0;
});

// Now that we are sorted by complexity, group elements of the same
// complexity.  Note that this is, at worst, N^2, but the vector is likely to
// be extremely short in practice.  Note that we take this approach because we
// do not want to depend on the addresses of the objects we are grouping.
for (unsigned i = 0, e = Ops.size(); i != e-2; ++i) {
  const SCEV *S = Ops[i];
  unsigned Complexity = S->getSCEVType();

  // If there are any objects of the same complexity and same value as this
  // one, group them.
  for (unsigned j = i+1; j != e && Ops[j]->getSCEVType() == Complexity; ++j) {
    if (Ops[j] == S) { // Found a duplicate.
      // Move it to immediately after i'th element.
      std::swap(Ops[i+1], Ops[j]);
      ++i;   // no need to rescan it.
      if (i == e-2) return;  // Done!
    }
  }
}
883}

885/// Returns true if \p Ops contains a huge SCEV (the subtree of S contains at
886/// least HugeExprThreshold nodes).
887static bool hasHugeExpression(ArrayRef<const SCEV *> Ops) {
return any_of(Ops, [](const SCEV *S) {
  return S->getExpressionSize() >= HugeExprThreshold;
});
891}

893//===----------------------------------------------------------------------===//
894//                      Simple SCEV method implementations
895//===----------------------------------------------------------------------===//

897/// Compute BC(It, K).  The result has width W.  Assume, K > 0.
898static const SCEV *BinomialCoefficient(const SCEV *It, unsigned K,
                                     ScalarEvolution &SE,
                                     Type *ResultTy) {
// Handle the simplest case efficiently.
if (K == 1)
  return SE.getTruncateOrZeroExtend(It, ResultTy);

// We are using the following formula for BC(It, K):
//
//   BC(It, K) = (It * (It - 1) * ... * (It - K + 1)) / K!
//
// Suppose, W is the bitwidth of the return value.  We must be prepared for
// overflow.  Hence, we must assure that the result of our computation is
// equal to the accurate one modulo 2^W.  Unfortunately, division isn't
// safe in modular arithmetic.
//
// However, this code doesn't use exactly that formula; the formula it uses
// is something like the following, where T is the number of factors of 2 in
// K! (i.e. trailing zeros in the binary representation of K!), and ^ is
// exponentiation:
//
//   BC(It, K) = (It * (It - 1) * ... * (It - K + 1)) / 2^T / (K! / 2^T)
//
// This formula is trivially equivalent to the previous formula.  However,
// this formula can be implemented much more efficiently.  The trick is that
// K! / 2^T is odd, and exact division by an odd number *is* safe in modular
// arithmetic.  To do exact division in modular arithmetic, all we have
// to do is multiply by the inverse.  Therefore, this step can be done at
// width W.
//
// The next issue is how to safely do the division by 2^T.  The way this
// is done is by doing the multiplication step at a width of at least W + T
// bits.  This way, the bottom W+T bits of the product are accurate. Then,
// when we perform the division by 2^T (which is equivalent to a right shift
// by T), the bottom W bits are accurate.  Extra bits are okay; they'll get
// truncated out after the division by 2^T.
//
// In comparison to just directly using the first formula, this technique
// is much more efficient; using the first formula requires W * K bits,
// but this formula less than W + K bits. Also, the first formula requires
// a division step, whereas this formula only requires multiplies and shifts.
//
// It doesn't matter whether the subtraction step is done in the calculation
// width or the input iteration count's width; if the subtraction overflows,
// the result must be zero anyway.  We prefer here to do it in the width of
// the induction variable because it helps a lot for certain cases; CodeGen
// isn't smart enough to ignore the overflow, which leads to much less
// efficient code if the width of the subtraction is wider than the native
// register width.
//
// (It's possible to not widen at all by pulling out factors of 2 before
// the multiplication; for example, K=2 can be calculated as
// It/2*(It+(It*INT_MIN/INT_MIN)+-1). However, it requires
// extra arithmetic, so it's not an obvious win, and it gets
// much more complicated for K > 3.)

// Protection from insane SCEVs; this bound is conservative,
// but it probably doesn't matter.
if (K > 1000)
  return SE.getCouldNotCompute();

unsigned W = SE.getTypeSizeInBits(ResultTy);

// Calculate K! / 2^T and T; we divide out the factors of two before
// multiplying for calculating K! / 2^T to avoid overflow.
// Other overflow doesn't matter because we only care about the bottom
// W bits of the result.
APInt OddFactorial(W, 1);
unsigned T = 1;
for (unsigned i = 3; i <= K; ++i) {
  APInt Mult(W, i);
  unsigned TwoFactors = Mult.countTrailingZeros();
  T += TwoFactors;
  Mult.lshrInPlace(TwoFactors);
  OddFactorial *= Mult;
}

// We need at least W + T bits for the multiplication step
unsigned CalculationBits = W + T;

// Calculate 2^T, at width T+W.
APInt DivFactor = APInt::getOneBitSet(CalculationBits, T);

// Calculate the multiplicative inverse of K! / 2^T;
// this multiplication factor will perform the exact division by
// K! / 2^T.
APInt Mod = APInt::getSignedMinValue(W+1);
APInt MultiplyFactor = OddFactorial.zext(W+1);
MultiplyFactor = MultiplyFactor.multiplicativeInverse(Mod);
MultiplyFactor = MultiplyFactor.trunc(W);

// Calculate the product, at width T+W
IntegerType *CalculationTy = IntegerType::get(SE.getContext(),
                                                    CalculationBits);
const SCEV *Dividend = SE.getTruncateOrZeroExtend(It, CalculationTy);
for (unsigned i = 1; i != K; ++i) {
  const SCEV *S = SE.getMinusSCEV(It, SE.getConstant(It->getType(), i));
  Dividend = SE.getMulExpr(Dividend,
                           SE.getTruncateOrZeroExtend(S, CalculationTy));
}

// Divide by 2^T
const SCEV *DivResult = SE.getUDivExpr(Dividend, SE.getConstant(DivFactor));

// Truncate the result, and divide by K! / 2^T.

return SE.getMulExpr(SE.getConstant(MultiplyFactor),
                     SE.getTruncateOrZeroExtend(DivResult, ResultTy));
1006}

1008/// Return the value of this chain of recurrences at the specified iteration
1009/// number.  We can evaluate this recurrence by multiplying each element in the
1010/// chain by the binomial coefficient corresponding to it.  In other words, we
1011/// can evaluate {A,+,B,+,C,+,D} as:
1012///
1013///   A*BC(It, 0) + B*BC(It, 1) + C*BC(It, 2) + D*BC(It, 3)
1014///
1015/// where BC(It, k) stands for binomial coefficient.
1016const SCEV *SCEVAddRecExpr::evaluateAtIteration(const SCEV *It,
                                              ScalarEvolution &SE) const {
const SCEV *Result = getStart();
for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
  // The computation is correct in the face of overflow provided that the
  // multiplication is performed _after_ the evaluation of the binomial
  // coefficient.
  const SCEV *Coeff = BinomialCoefficient(It, i, SE, getType());
  if (isa<SCEVCouldNotCompute>(Coeff))
    return Coeff;

  Result = SE.getAddExpr(Result, SE.getMulExpr(getOperand(i), Coeff));
}
return Result;
1030}

1032//===----------------------------------------------------------------------===//
1033//                    SCEV Expression folder implementations
1034//===----------------------------------------------------------------------===//

1036const SCEV *ScalarEvolution::getPtrToIntExpr(const SCEV *Op, Type *Ty,
                                           unsigned Depth) {
assert(Ty->isIntegerTy() && "Target type must be an integer type!")((Ty->isIntegerTy() && "Target type must be an integer type!"
) ? static_cast<void> (0) : __assert_fail ("Ty->isIntegerTy() && \"Target type must be an integer type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1038, __PRETTY_FUNCTION__));
assert(Depth <= 1 && "getPtrToIntExpr() should self-recurse at most once.")((Depth <= 1 && "getPtrToIntExpr() should self-recurse at most once."
) ? static_cast<void> (0) : __assert_fail ("Depth <= 1 && \"getPtrToIntExpr() should self-recurse at most once.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1039, __PRETTY_FUNCTION__));

// We could be called with an integer-typed operands during SCEV rewrites.
// Since the operand is an integer already, just perform zext/trunc/self cast.
if (!Op->getType()->isPointerTy())
  return getTruncateOrZeroExtend(Op, Ty);

// What would be an ID for such a SCEV cast expression?
FoldingSetNodeID ID;
ID.AddInteger(scPtrToInt);
ID.AddPointer(Op);

void *IP = nullptr;

// Is there already an expression for such a cast?
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP))
  return getTruncateOrZeroExtend(S, Ty);

// If not, is this expression something we can't reduce any further?
if (isa<SCEVUnknown>(Op)) {
  // Create an explicit cast node.
  // We can reuse the existing insert position since if we get here,
  // we won't have made any changes which would invalidate it.
  Type *IntPtrTy = getDataLayout().getIntPtrType(Op->getType());
  assert(getDataLayout().getTypeSizeInBits(getEffectiveSCEVType(((getDataLayout().getTypeSizeInBits(getEffectiveSCEVType( Op->
getType())) == getDataLayout().getTypeSizeInBits(IntPtrTy) &&
 "We can only model ptrtoint if SCEV's effective (integer) type is "
 "sufficiently wide to represent all possible pointer values."
) ? static_cast<void> (0) : __assert_fail ("getDataLayout().getTypeSizeInBits(getEffectiveSCEVType( Op->getType())) == getDataLayout().getTypeSizeInBits(IntPtrTy) && \"We can only model ptrtoint if SCEV's effective (integer) type is \" \"sufficiently wide to represent all possible pointer values.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1066, __PRETTY_FUNCTION__))
             Op->getType())) == getDataLayout().getTypeSizeInBits(IntPtrTy) &&((getDataLayout().getTypeSizeInBits(getEffectiveSCEVType( Op->
getType())) == getDataLayout().getTypeSizeInBits(IntPtrTy) &&
 "We can only model ptrtoint if SCEV's effective (integer) type is "
 "sufficiently wide to represent all possible pointer values."
) ? static_cast<void> (0) : __assert_fail ("getDataLayout().getTypeSizeInBits(getEffectiveSCEVType( Op->getType())) == getDataLayout().getTypeSizeInBits(IntPtrTy) && \"We can only model ptrtoint if SCEV's effective (integer) type is \" \"sufficiently wide to represent all possible pointer values.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1066, __PRETTY_FUNCTION__))
         "We can only model ptrtoint if SCEV's effective (integer) type is "((getDataLayout().getTypeSizeInBits(getEffectiveSCEVType( Op->
getType())) == getDataLayout().getTypeSizeInBits(IntPtrTy) &&
 "We can only model ptrtoint if SCEV's effective (integer) type is "
 "sufficiently wide to represent all possible pointer values."
) ? static_cast<void> (0) : __assert_fail ("getDataLayout().getTypeSizeInBits(getEffectiveSCEVType( Op->getType())) == getDataLayout().getTypeSizeInBits(IntPtrTy) && \"We can only model ptrtoint if SCEV's effective (integer) type is \" \"sufficiently wide to represent all possible pointer values.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1066, __PRETTY_FUNCTION__))
         "sufficiently wide to represent all possible pointer values.")((getDataLayout().getTypeSizeInBits(getEffectiveSCEVType( Op->
getType())) == getDataLayout().getTypeSizeInBits(IntPtrTy) &&
 "We can only model ptrtoint if SCEV's effective (integer) type is "
 "sufficiently wide to represent all possible pointer values."
) ? static_cast<void> (0) : __assert_fail ("getDataLayout().getTypeSizeInBits(getEffectiveSCEVType( Op->getType())) == getDataLayout().getTypeSizeInBits(IntPtrTy) && \"We can only model ptrtoint if SCEV's effective (integer) type is \" \"sufficiently wide to represent all possible pointer values.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1066, __PRETTY_FUNCTION__));
  SCEV *S = new (SCEVAllocator)
      SCEVPtrToIntExpr(ID.Intern(SCEVAllocator), Op, IntPtrTy);
  UniqueSCEVs.InsertNode(S, IP);
  addToLoopUseLists(S);
  return getTruncateOrZeroExtend(S, Ty);
}

assert(Depth == 0 &&((Depth == 0 && "getPtrToIntExpr() should not self-recurse for non-SCEVUnknown's."
) ? static_cast<void> (0) : __assert_fail ("Depth == 0 && \"getPtrToIntExpr() should not self-recurse for non-SCEVUnknown's.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1075, __PRETTY_FUNCTION__))
       "getPtrToIntExpr() should not self-recurse for non-SCEVUnknown's.")((Depth == 0 && "getPtrToIntExpr() should not self-recurse for non-SCEVUnknown's."
) ? static_cast<void> (0) : __assert_fail ("Depth == 0 && \"getPtrToIntExpr() should not self-recurse for non-SCEVUnknown's.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1075, __PRETTY_FUNCTION__));

// Otherwise, we've got some expression that is more complex than just a
// single SCEVUnknown. But we don't want to have a SCEVPtrToIntExpr of an
// arbitrary expression, we want to have SCEVPtrToIntExpr of an SCEVUnknown
// only, and the expressions must otherwise be integer-typed.
// So sink the cast down to the SCEVUnknown's.

/// The SCEVPtrToIntSinkingRewriter takes a scalar evolution expression,
/// which computes a pointer-typed value, and rewrites the whole expression
/// tree so that *all* the computations are done on integers, and the only
/// pointer-typed operands in the expression are SCEVUnknown.
class SCEVPtrToIntSinkingRewriter
    : public SCEVRewriteVisitor<SCEVPtrToIntSinkingRewriter> {
  using Base = SCEVRewriteVisitor<SCEVPtrToIntSinkingRewriter>;

public:
  SCEVPtrToIntSinkingRewriter(ScalarEvolution &SE) : SCEVRewriteVisitor(SE) {}

  static const SCEV *rewrite(const SCEV *Scev, ScalarEvolution &SE) {
    SCEVPtrToIntSinkingRewriter Rewriter(SE);
    return Rewriter.visit(Scev);
  }

  const SCEV *visit(const SCEV *S) {
    Type *STy = S->getType();
    // If the expression is not pointer-typed, just keep it as-is.
    if (!STy->isPointerTy())
      return S;
    // Else, recursively sink the cast down into it.
    return Base::visit(S);
  }

  const SCEV *visitAddExpr(const SCEVAddExpr *Expr) {
    SmallVector<const SCEV *, 2> Operands;
    bool Changed = false;
    for (auto *Op : Expr->operands()) {
      Operands.push_back(visit(Op));
      Changed |= Op != Operands.back();
    }
    return !Changed ? Expr : SE.getAddExpr(Operands, Expr->getNoWrapFlags());
  }

  const SCEV *visitMulExpr(const SCEVMulExpr *Expr) {
    SmallVector<const SCEV *, 2> Operands;
    bool Changed = false;
    for (auto *Op : Expr->operands()) {
      Operands.push_back(visit(Op));
      Changed |= Op != Operands.back();
    }
    return !Changed ? Expr : SE.getMulExpr(Operands, Expr->getNoWrapFlags());
  }

  const SCEV *visitUnknown(const SCEVUnknown *Expr) {
    Type *ExprPtrTy = Expr->getType();
    assert(ExprPtrTy->isPointerTy() &&((ExprPtrTy->isPointerTy() && "Should only reach pointer-typed SCEVUnknown's."
) ? static_cast<void> (0) : __assert_fail ("ExprPtrTy->isPointerTy() && \"Should only reach pointer-typed SCEVUnknown's.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1131, __PRETTY_FUNCTION__))
           "Should only reach pointer-typed SCEVUnknown's.")((ExprPtrTy->isPointerTy() && "Should only reach pointer-typed SCEVUnknown's."
) ? static_cast<void> (0) : __assert_fail ("ExprPtrTy->isPointerTy() && \"Should only reach pointer-typed SCEVUnknown's.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1131, __PRETTY_FUNCTION__));
    Type *ExprIntPtrTy = SE.getDataLayout().getIntPtrType(ExprPtrTy);
    return SE.getPtrToIntExpr(Expr, ExprIntPtrTy, /*Depth=*/1);
  }
};

// And actually perform the cast sinking.
const SCEV *IntOp = SCEVPtrToIntSinkingRewriter::rewrite(Op, *this);
assert(IntOp->getType()->isIntegerTy() &&((IntOp->getType()->isIntegerTy() && "We must have succeeded in sinking the cast, "
 "and ending up with an integer-typed expression!") ? static_cast
<void> (0) : __assert_fail ("IntOp->getType()->isIntegerTy() && \"We must have succeeded in sinking the cast, \" \"and ending up with an integer-typed expression!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1141, __PRETTY_FUNCTION__))
       "We must have succeeded in sinking the cast, "((IntOp->getType()->isIntegerTy() && "We must have succeeded in sinking the cast, "
 "and ending up with an integer-typed expression!") ? static_cast
<void> (0) : __assert_fail ("IntOp->getType()->isIntegerTy() && \"We must have succeeded in sinking the cast, \" \"and ending up with an integer-typed expression!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1141, __PRETTY_FUNCTION__))
       "and ending up with an integer-typed expression!")((IntOp->getType()->isIntegerTy() && "We must have succeeded in sinking the cast, "
 "and ending up with an integer-typed expression!") ? static_cast
<void> (0) : __assert_fail ("IntOp->getType()->isIntegerTy() && \"We must have succeeded in sinking the cast, \" \"and ending up with an integer-typed expression!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1141, __PRETTY_FUNCTION__));
return getTruncateOrZeroExtend(IntOp, Ty);
1143}

1145const SCEV *ScalarEvolution::getTruncateExpr(const SCEV *Op, Type *Ty,
                                           unsigned Depth) {
assert(getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(
Ty) && "This is not a truncating conversion!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) && \"This is not a truncating conversion!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1148, __PRETTY_FUNCTION__))
       "This is not a truncating conversion!")((getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(
Ty) && "This is not a truncating conversion!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) > getTypeSizeInBits(Ty) && \"This is not a truncating conversion!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1148, __PRETTY_FUNCTION__));
assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!"
) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1150, __PRETTY_FUNCTION__))
       "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!"
) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1150, __PRETTY_FUNCTION__));
Ty = getEffectiveSCEVType(Ty);

FoldingSetNodeID ID;
ID.AddInteger(scTruncate);
ID.AddPointer(Op);
ID.AddPointer(Ty);
void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;

// Fold if the operand is constant.
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
  return getConstant(
    cast<ConstantInt>(ConstantExpr::getTrunc(SC->getValue(), Ty)));

// trunc(trunc(x)) --> trunc(x)
if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op))
  return getTruncateExpr(ST->getOperand(), Ty, Depth + 1);

// trunc(sext(x)) --> sext(x) if widening or trunc(x) if narrowing
if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
  return getTruncateOrSignExtend(SS->getOperand(), Ty, Depth + 1);

// trunc(zext(x)) --> zext(x) if widening or trunc(x) if narrowing
if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
  return getTruncateOrZeroExtend(SZ->getOperand(), Ty, Depth + 1);

if (Depth > MaxCastDepth) {
  SCEV *S =
      new (SCEVAllocator) SCEVTruncateExpr(ID.Intern(SCEVAllocator), Op, Ty);
  UniqueSCEVs.InsertNode(S, IP);
  addToLoopUseLists(S);
  return S;
}

// trunc(x1 + ... + xN) --> trunc(x1) + ... + trunc(xN) and
// trunc(x1 * ... * xN) --> trunc(x1) * ... * trunc(xN),
// if after transforming we have at most one truncate, not counting truncates
// that replace other casts.
if (isa<SCEVAddExpr>(Op) || isa<SCEVMulExpr>(Op)) {
  auto *CommOp = cast<SCEVCommutativeExpr>(Op);
  SmallVector<const SCEV *, 4> Operands;
  unsigned numTruncs = 0;
  for (unsigned i = 0, e = CommOp->getNumOperands(); i != e && numTruncs < 2;
       ++i) {
    const SCEV *S = getTruncateExpr(CommOp->getOperand(i), Ty, Depth + 1);
    if (!isa<SCEVIntegralCastExpr>(CommOp->getOperand(i)) &&
        isa<SCEVTruncateExpr>(S))
      numTruncs++;
    Operands.push_back(S);
  }
  if (numTruncs < 2) {
    if (isa<SCEVAddExpr>(Op))
      return getAddExpr(Operands);
    else if (isa<SCEVMulExpr>(Op))
      return getMulExpr(Operands);
    else
      llvm_unreachable("Unexpected SCEV type for Op.")::llvm::llvm_unreachable_internal("Unexpected SCEV type for Op."
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1207);
  }
  // Although we checked in the beginning that ID is not in the cache, it is
  // possible that during recursion and different modification ID was inserted
  // into the cache. So if we find it, just return it.
  if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP))
    return S;
}

// If the input value is a chrec scev, truncate the chrec's operands.
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) {
  SmallVector<const SCEV *, 4> Operands;
  for (const SCEV *Op : AddRec->operands())
    Operands.push_back(getTruncateExpr(Op, Ty, Depth + 1));
  return getAddRecExpr(Operands, AddRec->getLoop(), SCEV::FlagAnyWrap);
}

// The cast wasn't folded; create an explicit cast node. We can reuse
// the existing insert position since if we get here, we won't have
// made any changes which would invalidate it.
SCEV *S = new (SCEVAllocator) SCEVTruncateExpr(ID.Intern(SCEVAllocator),
                                               Op, Ty);
UniqueSCEVs.InsertNode(S, IP);
addToLoopUseLists(S);
return S;
1232}

1234// Get the limit of a recurrence such that incrementing by Step cannot cause
1235// signed overflow as long as the value of the recurrence within the
1236// loop does not exceed this limit before incrementing.
1237static const SCEV *getSignedOverflowLimitForStep(const SCEV *Step,
                                               ICmpInst::Predicate *Pred,
                                               ScalarEvolution *SE) {
unsigned BitWidth = SE->getTypeSizeInBits(Step->getType());
if (SE->isKnownPositive(Step)) {
  *Pred = ICmpInst::ICMP_SLT;
  return SE->getConstant(APInt::getSignedMinValue(BitWidth) -
                         SE->getSignedRangeMax(Step));
}
if (SE->isKnownNegative(Step)) {
  *Pred = ICmpInst::ICMP_SGT;
  return SE->getConstant(APInt::getSignedMaxValue(BitWidth) -
                         SE->getSignedRangeMin(Step));
}
return nullptr;
1252}

1254// Get the limit of a recurrence such that incrementing by Step cannot cause
1255// unsigned overflow as long as the value of the recurrence within the loop does
1256// not exceed this limit before incrementing.
1257static const SCEV *getUnsignedOverflowLimitForStep(const SCEV *Step,
                                                 ICmpInst::Predicate *Pred,
                                                 ScalarEvolution *SE) {
unsigned BitWidth = SE->getTypeSizeInBits(Step->getType());
*Pred = ICmpInst::ICMP_ULT;

return SE->getConstant(APInt::getMinValue(BitWidth) -
                       SE->getUnsignedRangeMax(Step));
1265}

1267namespace {

1269struct ExtendOpTraitsBase {
typedef const SCEV *(ScalarEvolution::*GetExtendExprTy)(const SCEV *, Type *,
                                                        unsigned);
1272};

1274// Used to make code generic over signed and unsigned overflow.
1275template <typename ExtendOp> struct ExtendOpTraits {
// Members present:
//
// static const SCEV::NoWrapFlags WrapType;
//
// static const ExtendOpTraitsBase::GetExtendExprTy GetExtendExpr;
//
// static const SCEV *getOverflowLimitForStep(const SCEV *Step,
//                                           ICmpInst::Predicate *Pred,
//                                           ScalarEvolution *SE);
1285};

1287template <>
1288struct ExtendOpTraits<SCEVSignExtendExpr> : public ExtendOpTraitsBase {
static const SCEV::NoWrapFlags WrapType = SCEV::FlagNSW;

static const GetExtendExprTy GetExtendExpr;

static const SCEV *getOverflowLimitForStep(const SCEV *Step,
                                           ICmpInst::Predicate *Pred,
                                           ScalarEvolution *SE) {
  return getSignedOverflowLimitForStep(Step, Pred, SE);
}
1298};

1300const ExtendOpTraitsBase::GetExtendExprTy ExtendOpTraits<
  SCEVSignExtendExpr>::GetExtendExpr = &ScalarEvolution::getSignExtendExpr;

1303template <>
1304struct ExtendOpTraits<SCEVZeroExtendExpr> : public ExtendOpTraitsBase {
static const SCEV::NoWrapFlags WrapType = SCEV::FlagNUW;

static const GetExtendExprTy GetExtendExpr;

static const SCEV *getOverflowLimitForStep(const SCEV *Step,
                                           ICmpInst::Predicate *Pred,
                                           ScalarEvolution *SE) {
  return getUnsignedOverflowLimitForStep(Step, Pred, SE);
}
1314};

1316const ExtendOpTraitsBase::GetExtendExprTy ExtendOpTraits<
  SCEVZeroExtendExpr>::GetExtendExpr = &ScalarEvolution::getZeroExtendExpr;

1319} // end anonymous namespace

1321// The recurrence AR has been shown to have no signed/unsigned wrap or something
1322// close to it. Typically, if we can prove NSW/NUW for AR, then we can just as
1323// easily prove NSW/NUW for its preincrement or postincrement sibling. This
1324// allows normalizing a sign/zero extended AddRec as such: {sext/zext(Step +
1325// Start),+,Step} => {(Step + sext/zext(Start),+,Step} As a result, the
1326// expression "Step + sext/zext(PreIncAR)" is congruent with
1327// "sext/zext(PostIncAR)"
1328template <typename ExtendOpTy>
1329static const SCEV *getPreStartForExtend(const SCEVAddRecExpr *AR, Type *Ty,
                                      ScalarEvolution *SE, unsigned Depth) {
auto WrapType = ExtendOpTraits<ExtendOpTy>::WrapType;
auto GetExtendExpr = ExtendOpTraits<ExtendOpTy>::GetExtendExpr;

const Loop *L = AR->getLoop();
const SCEV *Start = AR->getStart();
const SCEV *Step = AR->getStepRecurrence(*SE);

// Check for a simple looking step prior to loop entry.
const SCEVAddExpr *SA = dyn_cast<SCEVAddExpr>(Start);
if (!SA)
  return nullptr;

// Create an AddExpr for "PreStart" after subtracting Step. Full SCEV
// subtraction is expensive. For this purpose, perform a quick and dirty
// difference, by checking for Step in the operand list.
SmallVector<const SCEV *, 4> DiffOps;
for (const SCEV *Op : SA->operands())
  if (Op != Step)
    DiffOps.push_back(Op);

if (DiffOps.size() == SA->getNumOperands())
  return nullptr;

// Try to prove `WrapType` (SCEV::FlagNSW or SCEV::FlagNUW) on `PreStart` +
// `Step`:

// 1. NSW/NUW flags on the step increment.
auto PreStartFlags =
  ScalarEvolution::maskFlags(SA->getNoWrapFlags(), SCEV::FlagNUW);
const SCEV *PreStart = SE->getAddExpr(DiffOps, PreStartFlags);
const SCEVAddRecExpr *PreAR = dyn_cast<SCEVAddRecExpr>(
    SE->getAddRecExpr(PreStart, Step, L, SCEV::FlagAnyWrap));

// "{S,+,X} is <nsw>/<nuw>" and "the backedge is taken at least once" implies
// "S+X does not sign/unsign-overflow".
//

const SCEV *BECount = SE->getBackedgeTakenCount(L);
if (PreAR && PreAR->getNoWrapFlags(WrapType) &&
    !isa<SCEVCouldNotCompute>(BECount) && SE->isKnownPositive(BECount))
  return PreStart;

// 2. Direct overflow check on the step operation's expression.
unsigned BitWidth = SE->getTypeSizeInBits(AR->getType());
Type *WideTy = IntegerType::get(SE->getContext(), BitWidth * 2);
const SCEV *OperandExtendedStart =
    SE->getAddExpr((SE->*GetExtendExpr)(PreStart, WideTy, Depth),
                   (SE->*GetExtendExpr)(Step, WideTy, Depth));
if ((SE->*GetExtendExpr)(Start, WideTy, Depth) == OperandExtendedStart) {
  if (PreAR && AR->getNoWrapFlags(WrapType)) {
    // If we know `AR` == {`PreStart`+`Step`,+,`Step`} is `WrapType` (FlagNSW
    // or FlagNUW) and that `PreStart` + `Step` is `WrapType` too, then
    // `PreAR` == {`PreStart`,+,`Step`} is also `WrapType`.  Cache this fact.
    SE->setNoWrapFlags(const_cast<SCEVAddRecExpr *>(PreAR), WrapType);
  }
  return PreStart;
}

// 3. Loop precondition.
ICmpInst::Predicate Pred;
const SCEV *OverflowLimit =
    ExtendOpTraits<ExtendOpTy>::getOverflowLimitForStep(Step, &Pred, SE);

if (OverflowLimit &&
    SE->isLoopEntryGuardedByCond(L, Pred, PreStart, OverflowLimit))
  return PreStart;

return nullptr;
1399}

1401// Get the normalized zero or sign extended expression for this AddRec's Start.
1402template <typename ExtendOpTy>
1403static const SCEV *getExtendAddRecStart(const SCEVAddRecExpr *AR, Type *Ty,
                                      ScalarEvolution *SE,
                                      unsigned Depth) {
auto GetExtendExpr = ExtendOpTraits<ExtendOpTy>::GetExtendExpr;

const SCEV *PreStart = getPreStartForExtend<ExtendOpTy>(AR, Ty, SE, Depth);
if (!PreStart)
  return (SE->*GetExtendExpr)(AR->getStart(), Ty, Depth);

return SE->getAddExpr((SE->*GetExtendExpr)(AR->getStepRecurrence(*SE), Ty,
                                           Depth),
                      (SE->*GetExtendExpr)(PreStart, Ty, Depth));
1415}

1417// Try to prove away overflow by looking at "nearby" add recurrences.  A
1418// motivating example for this rule: if we know `{0,+,4}` is `ult` `-1` and it
1419// does not itself wrap then we can conclude that `{1,+,4}` is `nuw`.
1420//
1421// Formally:
1422//
1423//     {S,+,X} == {S-T,+,X} + T
1424//  => Ext({S,+,X}) == Ext({S-T,+,X} + T)
1425//
1426// If ({S-T,+,X} + T) does not overflow  ... (1)
1427//
1428//  RHS == Ext({S-T,+,X} + T) == Ext({S-T,+,X}) + Ext(T)
1429//
1430// If {S-T,+,X} does not overflow  ... (2)
1431//
1432//  RHS == Ext({S-T,+,X}) + Ext(T) == {Ext(S-T),+,Ext(X)} + Ext(T)
1433//      == {Ext(S-T)+Ext(T),+,Ext(X)}
1434//
1435// If (S-T)+T does not overflow  ... (3)
1436//
1437//  RHS == {Ext(S-T)+Ext(T),+,Ext(X)} == {Ext(S-T+T),+,Ext(X)}
1438//      == {Ext(S),+,Ext(X)} == LHS
1439//
1440// Thus, if (1), (2) and (3) are true for some T, then
1441//   Ext({S,+,X}) == {Ext(S),+,Ext(X)}
1442//
1443// (3) is implied by (1) -- "(S-T)+T does not overflow" is simply "({S-T,+,X}+T)
1444// does not overflow" restricted to the 0th iteration.  Therefore we only need
1445// to check for (1) and (2).
1446//
1447// In the current context, S is `Start`, X is `Step`, Ext is `ExtendOpTy` and T
1448// is `Delta` (defined below).
1449template <typename ExtendOpTy>
1450bool ScalarEvolution::proveNoWrapByVaryingStart(const SCEV *Start,
                                              const SCEV *Step,
                                              const Loop *L) {
auto WrapType = ExtendOpTraits<ExtendOpTy>::WrapType;

// We restrict `Start` to a constant to prevent SCEV from spending too much
// time here.  It is correct (but more expensive) to continue with a
// non-constant `Start` and do a general SCEV subtraction to compute
// `PreStart` below.
const SCEVConstant *StartC = dyn_cast<SCEVConstant>(Start);
if (!StartC)
  return false;

APInt StartAI = StartC->getAPInt();

for (unsigned Delta : {-2, -1, 1, 2}) {
  const SCEV *PreStart = getConstant(StartAI - Delta);

  FoldingSetNodeID ID;
  ID.AddInteger(scAddRecExpr);
  ID.AddPointer(PreStart);
  ID.AddPointer(Step);
  ID.AddPointer(L);
  void *IP = nullptr;
  const auto *PreAR =
    static_cast<SCEVAddRecExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));

  // Give up if we don't already have the add recurrence we need because
  // actually constructing an add recurrence is relatively expensive.
  if (PreAR && PreAR->getNoWrapFlags(WrapType)) {  // proves (2)
    const SCEV *DeltaS = getConstant(StartC->getType(), Delta);
    ICmpInst::Predicate Pred = ICmpInst::BAD_ICMP_PREDICATE;
    const SCEV *Limit = ExtendOpTraits<ExtendOpTy>::getOverflowLimitForStep(
        DeltaS, &Pred, this);
    if (Limit && isKnownPredicate(Pred, PreAR, Limit))  // proves (1)
      return true;
  }
}

return false;
1490}

1492// Finds an integer D for an expression (C + x + y + ...) such that the top
1493// level addition in (D + (C - D + x + y + ...)) would not wrap (signed or
1494// unsigned) and the number of trailing zeros of (C - D + x + y + ...) is
1495// maximized, where C is the \p ConstantTerm, x, y, ... are arbitrary SCEVs, and
1496// the (C + x + y + ...) expression is \p WholeAddExpr.
1497static APInt extractConstantWithoutWrapping(ScalarEvolution &SE,
                                          const SCEVConstant *ConstantTerm,
                                          const SCEVAddExpr *WholeAddExpr) {
const APInt &C = ConstantTerm->getAPInt();
const unsigned BitWidth = C.getBitWidth();
// Find number of trailing zeros of (x + y + ...) w/o the C first:
uint32_t TZ = BitWidth;
for (unsigned I = 1, E = WholeAddExpr->getNumOperands(); I < E && TZ; ++I)
  TZ = std::min(TZ, SE.GetMinTrailingZeros(WholeAddExpr->getOperand(I)));
if (TZ) {
  // Set D to be as many least significant bits of C as possible while still
  // guaranteeing that adding D to (C - D + x + y + ...) won't cause a wrap:
  return TZ < BitWidth ? C.trunc(TZ).zext(BitWidth) : C;
}
return APInt(BitWidth, 0);
1512}

1514// Finds an integer D for an affine AddRec expression {C,+,x} such that the top
1515// level addition in (D + {C-D,+,x}) would not wrap (signed or unsigned) and the
1516// number of trailing zeros of (C - D + x * n) is maximized, where C is the \p
1517// ConstantStart, x is an arbitrary \p Step, and n is the loop trip count.
1518static APInt extractConstantWithoutWrapping(ScalarEvolution &SE,
                                          const APInt &ConstantStart,
                                          const SCEV *Step) {
const unsigned BitWidth = ConstantStart.getBitWidth();
const uint32_t TZ = SE.GetMinTrailingZeros(Step);
if (TZ)
  return TZ < BitWidth ? ConstantStart.trunc(TZ).zext(BitWidth)
                       : ConstantStart;
return APInt(BitWidth, 0);
1527}

1529const SCEV *
1530ScalarEvolution::getZeroExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(
Ty) && "This is not an extending conversion!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1532, __PRETTY_FUNCTION__))
       "This is not an extending conversion!")((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(
Ty) && "This is not an extending conversion!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1532, __PRETTY_FUNCTION__));
assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!"
) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1534, __PRETTY_FUNCTION__))
       "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!"
) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1534, __PRETTY_FUNCTION__));
Ty = getEffectiveSCEVType(Ty);

// Fold if the operand is constant.
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
  return getConstant(
    cast<ConstantInt>(ConstantExpr::getZExt(SC->getValue(), Ty)));

// zext(zext(x)) --> zext(x)
if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
  return getZeroExtendExpr(SZ->getOperand(), Ty, Depth + 1);

// Before doing any expensive analysis, check to see if we've already
// computed a SCEV for this Op and Ty.
FoldingSetNodeID ID;
ID.AddInteger(scZeroExtend);
ID.AddPointer(Op);
ID.AddPointer(Ty);
void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
if (Depth > MaxCastDepth) {
  SCEV *S = new (SCEVAllocator) SCEVZeroExtendExpr(ID.Intern(SCEVAllocator),
                                                   Op, Ty);
  UniqueSCEVs.InsertNode(S, IP);
  addToLoopUseLists(S);
  return S;
}

// zext(trunc(x)) --> zext(x) or x or trunc(x)
if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op)) {
  // It's possible the bits taken off by the truncate were all zero bits. If
  // so, we should be able to simplify this further.
  const SCEV *X = ST->getOperand();
  ConstantRange CR = getUnsignedRange(X);
  unsigned TruncBits = getTypeSizeInBits(ST->getType());
  unsigned NewBits = getTypeSizeInBits(Ty);
  if (CR.truncate(TruncBits).zeroExtend(NewBits).contains(
          CR.zextOrTrunc(NewBits)))
    return getTruncateOrZeroExtend(X, Ty, Depth);
}

// If the input value is a chrec scev, and we can prove that the value
// did not overflow the old, smaller, value, we can zero extend all of the
// operands (often constants).  This allows analysis of something like
// this:  for (unsigned char X = 0; X < 100; ++X) { int Y = X; }
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op))
  if (AR->isAffine()) {
    const SCEV *Start = AR->getStart();
    const SCEV *Step = AR->getStepRecurrence(*this);
    unsigned BitWidth = getTypeSizeInBits(AR->getType());
    const Loop *L = AR->getLoop();

    if (!AR->hasNoUnsignedWrap()) {
      auto NewFlags = proveNoWrapViaConstantRanges(AR);
      setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), NewFlags);
    }

    // If we have special knowledge that this addrec won't overflow,
    // we don't need to do any further analysis.
    if (AR->hasNoUnsignedWrap())
      return getAddRecExpr(
          getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, Depth + 1),
          getZeroExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());

    // Check whether the backedge-taken count is SCEVCouldNotCompute.
    // Note that this serves two purposes: It filters out loops that are
    // simply not analyzable, and it covers the case where this code is
    // being called from within backedge-taken count analysis, such that
    // attempting to ask for the backedge-taken count would likely result
    // in infinite recursion. In the later case, the analysis code will
    // cope with a conservative value, and it will take care to purge
    // that value once it has finished.
    const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(L);
    if (!isa<SCEVCouldNotCompute>(MaxBECount)) {
      // Manually compute the final value for AR, checking for overflow.

      // Check whether the backedge-taken count can be losslessly casted to
      // the addrec's type. The count is always unsigned.
      const SCEV *CastedMaxBECount =
          getTruncateOrZeroExtend(MaxBECount, Start->getType(), Depth);
      const SCEV *RecastedMaxBECount = getTruncateOrZeroExtend(
          CastedMaxBECount, MaxBECount->getType(), Depth);
      if (MaxBECount == RecastedMaxBECount) {
        Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
        // Check whether Start+Step*MaxBECount has no unsigned overflow.
        const SCEV *ZMul = getMulExpr(CastedMaxBECount, Step,
                                      SCEV::FlagAnyWrap, Depth + 1);
        const SCEV *ZAdd = getZeroExtendExpr(getAddExpr(Start, ZMul,
                                                        SCEV::FlagAnyWrap,
                                                        Depth + 1),
                                             WideTy, Depth + 1);
        const SCEV *WideStart = getZeroExtendExpr(Start, WideTy, Depth + 1);
        const SCEV *WideMaxBECount =
          getZeroExtendExpr(CastedMaxBECount, WideTy, Depth + 1);
        const SCEV *OperandExtendedAdd =
          getAddExpr(WideStart,
                     getMulExpr(WideMaxBECount,
                                getZeroExtendExpr(Step, WideTy, Depth + 1),
                                SCEV::FlagAnyWrap, Depth + 1),
                     SCEV::FlagAnyWrap, Depth + 1);
        if (ZAdd == OperandExtendedAdd) {
          // Cache knowledge of AR NUW, which is propagated to this AddRec.
          setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNUW);
          // Return the expression with the addrec on the outside.
          return getAddRecExpr(
              getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
                                                       Depth + 1),
              getZeroExtendExpr(Step, Ty, Depth + 1), L,
              AR->getNoWrapFlags());
        }
        // Similar to above, only this time treat the step value as signed.
        // This covers loops that count down.
        OperandExtendedAdd =
          getAddExpr(WideStart,
                     getMulExpr(WideMaxBECount,
                                getSignExtendExpr(Step, WideTy, Depth + 1),
                                SCEV::FlagAnyWrap, Depth + 1),
                     SCEV::FlagAnyWrap, Depth + 1);
        if (ZAdd == OperandExtendedAdd) {
          // Cache knowledge of AR NW, which is propagated to this AddRec.
          // Negative step causes unsigned wrap, but it still can't self-wrap.
          setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNW);
          // Return the expression with the addrec on the outside.
          return getAddRecExpr(
              getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
                                                       Depth + 1),
              getSignExtendExpr(Step, Ty, Depth + 1), L,
              AR->getNoWrapFlags());
        }
      }
    }

    // Normally, in the cases we can prove no-overflow via a
    // backedge guarding condition, we can also compute a backedge
    // taken count for the loop.  The exceptions are assumptions and
    // guards present in the loop -- SCEV is not great at exploiting
    // these to compute max backedge taken counts, but can still use
    // these to prove lack of overflow.  Use this fact to avoid
    // doing extra work that may not pay off.
    if (!isa<SCEVCouldNotCompute>(MaxBECount) || HasGuards ||
        !AC.assumptions().empty()) {

      auto NewFlags = proveNoUnsignedWrapViaInduction(AR);
      setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), NewFlags);
      if (AR->hasNoUnsignedWrap()) {
        // Same as nuw case above - duplicated here to avoid a compile time
        // issue.  It's not clear that the order of checks does matter, but
        // it's one of two issue possible causes for a change which was
        // reverted.  Be conservative for the moment.
        return getAddRecExpr(
              getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
                                                       Depth + 1),
              getZeroExtendExpr(Step, Ty, Depth + 1), L,
              AR->getNoWrapFlags());
      }
      
      // For a negative step, we can extend the operands iff doing so only
      // traverses values in the range zext([0,UINT_MAX]). 
      if (isKnownNegative(Step)) {
        const SCEV *N = getConstant(APInt::getMaxValue(BitWidth) -
                                    getSignedRangeMin(Step));
        if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_UGT, AR, N) ||
            isKnownOnEveryIteration(ICmpInst::ICMP_UGT, AR, N)) {
          // Cache knowledge of AR NW, which is propagated to this
          // AddRec.  Negative step causes unsigned wrap, but it
          // still can't self-wrap.
          setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNW);
          // Return the expression with the addrec on the outside.
          return getAddRecExpr(
              getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this,
                                                       Depth + 1),
              getSignExtendExpr(Step, Ty, Depth + 1), L,
              AR->getNoWrapFlags());
        }
      }
    }

    // zext({C,+,Step}) --> (zext(D) + zext({C-D,+,Step}))<nuw><nsw>
    // if D + (C - D + Step * n) could be proven to not unsigned wrap
    // where D maximizes the number of trailing zeros of (C - D + Step * n)
    if (const auto *SC = dyn_cast<SCEVConstant>(Start)) {
      const APInt &C = SC->getAPInt();
      const APInt &D = extractConstantWithoutWrapping(*this, C, Step);
      if (D != 0) {
        const SCEV *SZExtD = getZeroExtendExpr(getConstant(D), Ty, Depth);
        const SCEV *SResidual =
            getAddRecExpr(getConstant(C - D), Step, L, AR->getNoWrapFlags());
        const SCEV *SZExtR = getZeroExtendExpr(SResidual, Ty, Depth + 1);
        return getAddExpr(SZExtD, SZExtR,
                          (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW),
                          Depth + 1);
      }
    }

    if (proveNoWrapByVaryingStart<SCEVZeroExtendExpr>(Start, Step, L)) {
      setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNUW);
      return getAddRecExpr(
          getExtendAddRecStart<SCEVZeroExtendExpr>(AR, Ty, this, Depth + 1),
          getZeroExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());
    }
  }

// zext(A % B) --> zext(A) % zext(B)
{
  const SCEV *LHS;
  const SCEV *RHS;
  if (matchURem(Op, LHS, RHS))
    return getURemExpr(getZeroExtendExpr(LHS, Ty, Depth + 1),
                       getZeroExtendExpr(RHS, Ty, Depth + 1));
}

// zext(A / B) --> zext(A) / zext(B).
if (auto *Div = dyn_cast<SCEVUDivExpr>(Op))
  return getUDivExpr(getZeroExtendExpr(Div->getLHS(), Ty, Depth + 1),
                     getZeroExtendExpr(Div->getRHS(), Ty, Depth + 1));

if (auto *SA = dyn_cast<SCEVAddExpr>(Op)) {
  // zext((A + B + ...)<nuw>) --> (zext(A) + zext(B) + ...)<nuw>
  if (SA->hasNoUnsignedWrap()) {
    // If the addition does not unsign overflow then we can, by definition,
    // commute the zero extension with the addition operation.
    SmallVector<const SCEV *, 4> Ops;
    for (const auto *Op : SA->operands())
      Ops.push_back(getZeroExtendExpr(Op, Ty, Depth + 1));
    return getAddExpr(Ops, SCEV::FlagNUW, Depth + 1);
  }

  // zext(C + x + y + ...) --> (zext(D) + zext((C - D) + x + y + ...))
  // if D + (C - D + x + y + ...) could be proven to not unsigned wrap
  // where D maximizes the number of trailing zeros of (C - D + x + y + ...)
  //
  // Often address arithmetics contain expressions like
  // (zext (add (shl X, C1), C2)), for instance, (zext (5 + (4 * X))).
  // This transformation is useful while proving that such expressions are
  // equal or differ by a small constant amount, see LoadStoreVectorizer pass.
  if (const auto *SC = dyn_cast<SCEVConstant>(SA->getOperand(0))) {
    const APInt &D = extractConstantWithoutWrapping(*this, SC, SA);
    if (D != 0) {
      const SCEV *SZExtD = getZeroExtendExpr(getConstant(D), Ty, Depth);
      const SCEV *SResidual =
          getAddExpr(getConstant(-D), SA, SCEV::FlagAnyWrap, Depth);
      const SCEV *SZExtR = getZeroExtendExpr(SResidual, Ty, Depth + 1);
      return getAddExpr(SZExtD, SZExtR,
                        (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW),
                        Depth + 1);
    }
  }
}

if (auto *SM = dyn_cast<SCEVMulExpr>(Op)) {
  // zext((A * B * ...)<nuw>) --> (zext(A) * zext(B) * ...)<nuw>
  if (SM->hasNoUnsignedWrap()) {
    // If the multiply does not unsign overflow then we can, by definition,
    // commute the zero extension with the multiply operation.
    SmallVector<const SCEV *, 4> Ops;
    for (const auto *Op : SM->operands())
      Ops.push_back(getZeroExtendExpr(Op, Ty, Depth + 1));
    return getMulExpr(Ops, SCEV::FlagNUW, Depth + 1);
  }

  // zext(2^K * (trunc X to iN)) to iM ->
  // 2^K * (zext(trunc X to i{N-K}) to iM)<nuw>
  //
  // Proof:
  //
  //     zext(2^K * (trunc X to iN)) to iM
  //   = zext((trunc X to iN) << K) to iM
  //   = zext((trunc X to i{N-K}) << K)<nuw> to iM
  //     (because shl removes the top K bits)
  //   = zext((2^K * (trunc X to i{N-K}))<nuw>) to iM
  //   = (2^K * (zext(trunc X to i{N-K}) to iM))<nuw>.
  //
  if (SM->getNumOperands() == 2)
    if (auto *MulLHS = dyn_cast<SCEVConstant>(SM->getOperand(0)))
      if (MulLHS->getAPInt().isPowerOf2())
        if (auto *TruncRHS = dyn_cast<SCEVTruncateExpr>(SM->getOperand(1))) {
          int NewTruncBits = getTypeSizeInBits(TruncRHS->getType()) -
                             MulLHS->getAPInt().logBase2();
          Type *NewTruncTy = IntegerType::get(getContext(), NewTruncBits);
          return getMulExpr(
              getZeroExtendExpr(MulLHS, Ty),
              getZeroExtendExpr(
                  getTruncateExpr(TruncRHS->getOperand(), NewTruncTy), Ty),
              SCEV::FlagNUW, Depth + 1);
        }
}

// The cast wasn't folded; create an explicit cast node.
// Recompute the insert position, as it may have been invalidated.
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
SCEV *S = new (SCEVAllocator) SCEVZeroExtendExpr(ID.Intern(SCEVAllocator),
                                                 Op, Ty);
UniqueSCEVs.InsertNode(S, IP);
addToLoopUseLists(S);
return S;
1829}

1831const SCEV *
1832ScalarEvolution::getSignExtendExpr(const SCEV *Op, Type *Ty, unsigned Depth) {
assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(
Ty) && "This is not an extending conversion!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1834, __PRETTY_FUNCTION__))
       "This is not an extending conversion!")((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(
Ty) && "This is not an extending conversion!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1834, __PRETTY_FUNCTION__));
assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!"
) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1836, __PRETTY_FUNCTION__))
       "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!"
) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 1836, __PRETTY_FUNCTION__));
Ty = getEffectiveSCEVType(Ty);

// Fold if the operand is constant.
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
  return getConstant(
    cast<ConstantInt>(ConstantExpr::getSExt(SC->getValue(), Ty)));

// sext(sext(x)) --> sext(x)
if (const SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
  return getSignExtendExpr(SS->getOperand(), Ty, Depth + 1);

// sext(zext(x)) --> zext(x)
if (const SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
  return getZeroExtendExpr(SZ->getOperand(), Ty, Depth + 1);

// Before doing any expensive analysis, check to see if we've already
// computed a SCEV for this Op and Ty.
FoldingSetNodeID ID;
ID.AddInteger(scSignExtend);
ID.AddPointer(Op);
ID.AddPointer(Ty);
void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
// Limit recursion depth.
if (Depth > MaxCastDepth) {
  SCEV *S = new (SCEVAllocator) SCEVSignExtendExpr(ID.Intern(SCEVAllocator),
                                                   Op, Ty);
  UniqueSCEVs.InsertNode(S, IP);
  addToLoopUseLists(S);
  return S;
}

// sext(trunc(x)) --> sext(x) or x or trunc(x)
if (const SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op)) {
  // It's possible the bits taken off by the truncate were all sign bits. If
  // so, we should be able to simplify this further.
  const SCEV *X = ST->getOperand();
  ConstantRange CR = getSignedRange(X);
  unsigned TruncBits = getTypeSizeInBits(ST->getType());
  unsigned NewBits = getTypeSizeInBits(Ty);
  if (CR.truncate(TruncBits).signExtend(NewBits).contains(
          CR.sextOrTrunc(NewBits)))
    return getTruncateOrSignExtend(X, Ty, Depth);
}

if (auto *SA = dyn_cast<SCEVAddExpr>(Op)) {
  // sext((A + B + ...)<nsw>) --> (sext(A) + sext(B) + ...)<nsw>
  if (SA->hasNoSignedWrap()) {
    // If the addition does not sign overflow then we can, by definition,
    // commute the sign extension with the addition operation.
    SmallVector<const SCEV *, 4> Ops;
    for (const auto *Op : SA->operands())
      Ops.push_back(getSignExtendExpr(Op, Ty, Depth + 1));
    return getAddExpr(Ops, SCEV::FlagNSW, Depth + 1);
  }

  // sext(C + x + y + ...) --> (sext(D) + sext((C - D) + x + y + ...))
  // if D + (C - D + x + y + ...) could be proven to not signed wrap
  // where D maximizes the number of trailing zeros of (C - D + x + y + ...)
  //
  // For instance, this will bring two seemingly different expressions:
  //     1 + sext(5 + 20 * %x + 24 * %y)  and
  //         sext(6 + 20 * %x + 24 * %y)
  // to the same form:
  //     2 + sext(4 + 20 * %x + 24 * %y)
  if (const auto *SC = dyn_cast<SCEVConstant>(SA->getOperand(0))) {
    const APInt &D = extractConstantWithoutWrapping(*this, SC, SA);
    if (D != 0) {
      const SCEV *SSExtD = getSignExtendExpr(getConstant(D), Ty, Depth);
      const SCEV *SResidual =
          getAddExpr(getConstant(-D), SA, SCEV::FlagAnyWrap, Depth);
      const SCEV *SSExtR = getSignExtendExpr(SResidual, Ty, Depth + 1);
      return getAddExpr(SSExtD, SSExtR,
                        (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW),
                        Depth + 1);
    }
  }
}
// If the input value is a chrec scev, and we can prove that the value
// did not overflow the old, smaller, value, we can sign extend all of the
// operands (often constants).  This allows analysis of something like
// this:  for (signed char X = 0; X < 100; ++X) { int Y = X; }
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op))
  if (AR->isAffine()) {
    const SCEV *Start = AR->getStart();
    const SCEV *Step = AR->getStepRecurrence(*this);
    unsigned BitWidth = getTypeSizeInBits(AR->getType());
    const Loop *L = AR->getLoop();

    if (!AR->hasNoSignedWrap()) {
      auto NewFlags = proveNoWrapViaConstantRanges(AR);
      setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), NewFlags);
    }

    // If we have special knowledge that this addrec won't overflow,
    // we don't need to do any further analysis.
    if (AR->hasNoSignedWrap())
      return getAddRecExpr(
          getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1),
          getSignExtendExpr(Step, Ty, Depth + 1), L, SCEV::FlagNSW);

    // Check whether the backedge-taken count is SCEVCouldNotCompute.
    // Note that this serves two purposes: It filters out loops that are
    // simply not analyzable, and it covers the case where this code is
    // being called from within backedge-taken count analysis, such that
    // attempting to ask for the backedge-taken count would likely result
    // in infinite recursion. In the later case, the analysis code will
    // cope with a conservative value, and it will take care to purge
    // that value once it has finished.
    const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(L);
    if (!isa<SCEVCouldNotCompute>(MaxBECount)) {
      // Manually compute the final value for AR, checking for
      // overflow.

      // Check whether the backedge-taken count can be losslessly casted to
      // the addrec's type. The count is always unsigned.
      const SCEV *CastedMaxBECount =
          getTruncateOrZeroExtend(MaxBECount, Start->getType(), Depth);
      const SCEV *RecastedMaxBECount = getTruncateOrZeroExtend(
          CastedMaxBECount, MaxBECount->getType(), Depth);
      if (MaxBECount == RecastedMaxBECount) {
        Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
        // Check whether Start+Step*MaxBECount has no signed overflow.
        const SCEV *SMul = getMulExpr(CastedMaxBECount, Step,
                                      SCEV::FlagAnyWrap, Depth + 1);
        const SCEV *SAdd = getSignExtendExpr(getAddExpr(Start, SMul,
                                                        SCEV::FlagAnyWrap,
                                                        Depth + 1),
                                             WideTy, Depth + 1);
        const SCEV *WideStart = getSignExtendExpr(Start, WideTy, Depth + 1);
        const SCEV *WideMaxBECount =
          getZeroExtendExpr(CastedMaxBECount, WideTy, Depth + 1);
        const SCEV *OperandExtendedAdd =
          getAddExpr(WideStart,
                     getMulExpr(WideMaxBECount,
                                getSignExtendExpr(Step, WideTy, Depth + 1),
                                SCEV::FlagAnyWrap, Depth + 1),
                     SCEV::FlagAnyWrap, Depth + 1);
        if (SAdd == OperandExtendedAdd) {
          // Cache knowledge of AR NSW, which is propagated to this AddRec.
          setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNSW);
          // Return the expression with the addrec on the outside.
          return getAddRecExpr(
              getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this,
                                                       Depth + 1),
              getSignExtendExpr(Step, Ty, Depth + 1), L,
              AR->getNoWrapFlags());
        }
        // Similar to above, only this time treat the step value as unsigned.
        // This covers loops that count up with an unsigned step.
        OperandExtendedAdd =
          getAddExpr(WideStart,
                     getMulExpr(WideMaxBECount,
                                getZeroExtendExpr(Step, WideTy, Depth + 1),
                                SCEV::FlagAnyWrap, Depth + 1),
                     SCEV::FlagAnyWrap, Depth + 1);
        if (SAdd == OperandExtendedAdd) {
          // If AR wraps around then
          //
          //    abs(Step) * MaxBECount > unsigned-max(AR->getType())
          // => SAdd != OperandExtendedAdd
          //
          // Thus (AR is not NW => SAdd != OperandExtendedAdd) <=>
          // (SAdd == OperandExtendedAdd => AR is NW)

          setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNW);

          // Return the expression with the addrec on the outside.
          return getAddRecExpr(
              getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this,
                                                       Depth + 1),
              getZeroExtendExpr(Step, Ty, Depth + 1), L,
              AR->getNoWrapFlags());
        }
      }
    }

    auto NewFlags = proveNoSignedWrapViaInduction(AR);
    setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), NewFlags);
    if (AR->hasNoSignedWrap()) {
      // Same as nsw case above - duplicated here to avoid a compile time
      // issue.  It's not clear that the order of checks does matter, but
      // it's one of two issue possible causes for a change which was
      // reverted.  Be conservative for the moment.
      return getAddRecExpr(
          getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1),
          getSignExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());
    }

    // sext({C,+,Step}) --> (sext(D) + sext({C-D,+,Step}))<nuw><nsw>
    // if D + (C - D + Step * n) could be proven to not signed wrap
    // where D maximizes the number of trailing zeros of (C - D + Step * n)
    if (const auto *SC = dyn_cast<SCEVConstant>(Start)) {
      const APInt &C = SC->getAPInt();
      const APInt &D = extractConstantWithoutWrapping(*this, C, Step);
      if (D != 0) {
        const SCEV *SSExtD = getSignExtendExpr(getConstant(D), Ty, Depth);
        const SCEV *SResidual =
            getAddRecExpr(getConstant(C - D), Step, L, AR->getNoWrapFlags());
        const SCEV *SSExtR = getSignExtendExpr(SResidual, Ty, Depth + 1);
        return getAddExpr(SSExtD, SSExtR,
                          (SCEV::NoWrapFlags)(SCEV::FlagNSW | SCEV::FlagNUW),
                          Depth + 1);
      }
    }

    if (proveNoWrapByVaryingStart<SCEVSignExtendExpr>(Start, Step, L)) {
      setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), SCEV::FlagNSW);
      return getAddRecExpr(
          getExtendAddRecStart<SCEVSignExtendExpr>(AR, Ty, this, Depth + 1),
          getSignExtendExpr(Step, Ty, Depth + 1), L, AR->getNoWrapFlags());
    }
  }

// If the input value is provably positive and we could not simplify
// away the sext build a zext instead.
if (isKnownNonNegative(Op))
  return getZeroExtendExpr(Op, Ty, Depth + 1);

// The cast wasn't folded; create an explicit cast node.
// Recompute the insert position, as it may have been invalidated.
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
SCEV *S = new (SCEVAllocator) SCEVSignExtendExpr(ID.Intern(SCEVAllocator),
                                                 Op, Ty);
UniqueSCEVs.InsertNode(S, IP);
addToLoopUseLists(S);
return S;
2064}

2066/// getAnyExtendExpr - Return a SCEV for the given operand extended with
2067/// unspecified bits out to the given type.
2068const SCEV *ScalarEvolution::getAnyExtendExpr(const SCEV *Op,
                                            Type *Ty) {
assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(
Ty) && "This is not an extending conversion!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2071, __PRETTY_FUNCTION__))
       "This is not an extending conversion!")((getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(
Ty) && "This is not an extending conversion!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) && \"This is not an extending conversion!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2071, __PRETTY_FUNCTION__));
assert(isSCEVable(Ty) &&((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!"
) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2073, __PRETTY_FUNCTION__))
       "This is not a conversion to a SCEVable type!")((isSCEVable(Ty) && "This is not a conversion to a SCEVable type!"
) ? static_cast<void> (0) : __assert_fail ("isSCEVable(Ty) && \"This is not a conversion to a SCEVable type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2073, __PRETTY_FUNCTION__));
Ty = getEffectiveSCEVType(Ty);

// Sign-extend negative constants.
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
  if (SC->getAPInt().isNegative())
    return getSignExtendExpr(Op, Ty);

// Peel off a truncate cast.
if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Op)) {
  const SCEV *NewOp = T->getOperand();
  if (getTypeSizeInBits(NewOp->getType()) < getTypeSizeInBits(Ty))
    return getAnyExtendExpr(NewOp, Ty);
  return getTruncateOrNoop(NewOp, Ty);
}

// Next try a zext cast. If the cast is folded, use it.
const SCEV *ZExt = getZeroExtendExpr(Op, Ty);
if (!isa<SCEVZeroExtendExpr>(ZExt))
  return ZExt;

// Next try a sext cast. If the cast is folded, use it.
const SCEV *SExt = getSignExtendExpr(Op, Ty);
if (!isa<SCEVSignExtendExpr>(SExt))
  return SExt;

// Force the cast to be folded into the operands of an addrec.
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Op)) {
  SmallVector<const SCEV *, 4> Ops;
  for (const SCEV *Op : AR->operands())
    Ops.push_back(getAnyExtendExpr(Op, Ty));
  return getAddRecExpr(Ops, AR->getLoop(), SCEV::FlagNW);
}

// If the expression is obviously signed, use the sext cast value.
if (isa<SCEVSMaxExpr>(Op))
  return SExt;

// Absent any other information, use the zext cast value.
return ZExt;
2113}

2115/// Process the given Ops list, which is a list of operands to be added under
2116/// the given scale, update the given map. This is a helper function for
2117/// getAddRecExpr. As an example of what it does, given a sequence of operands
2118/// that would form an add expression like this:
2119///
2120///    m + n + 13 + (A * (o + p + (B * (q + m + 29)))) + r + (-1 * r)
2121///
2122/// where A and B are constants, update the map with these values:
2123///
2124///    (m, 1+A*B), (n, 1), (o, A), (p, A), (q, A*B), (r, 0)
2125///
2126/// and add 13 + A*B*29 to AccumulatedConstant.
2127/// This will allow getAddRecExpr to produce this:
2128///
2129///    13+A*B*29 + n + (m * (1+A*B)) + ((o + p) * A) + (q * A*B)
2130///
2131/// This form often exposes folding opportunities that are hidden in
2132/// the original operand list.
2133///
2134/// Return true iff it appears that any interesting folding opportunities
2135/// may be exposed. This helps getAddRecExpr short-circuit extra work in
2136/// the common case where no interesting opportunities are present, and
2137/// is also used as a check to avoid infinite recursion.
2138static bool
2139CollectAddOperandsWithScales(DenseMap<const SCEV *, APInt> &M,
                           SmallVectorImpl<const SCEV *> &NewOps,
                           APInt &AccumulatedConstant,
                           const SCEV *const *Ops, size_t NumOperands,
                           const APInt &Scale,
                           ScalarEvolution &SE) {
bool Interesting = false;

// Iterate over the add operands. They are sorted, with constants first.
unsigned i = 0;
while (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
  ++i;
  // Pull a buried constant out to the outside.
  if (Scale != 1 || AccumulatedConstant != 0 || C->getValue()->isZero())
    Interesting = true;
  AccumulatedConstant += Scale * C->getAPInt();
}

// Next comes everything else. We're especially interested in multiplies
// here, but they're in the middle, so just visit the rest with one loop.
for (; i != NumOperands; ++i) {
  const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[i]);
  if (Mul && isa<SCEVConstant>(Mul->getOperand(0))) {
    APInt NewScale =
        Scale * cast<SCEVConstant>(Mul->getOperand(0))->getAPInt();
    if (Mul->getNumOperands() == 2 && isa<SCEVAddExpr>(Mul->getOperand(1))) {
      // A multiplication of a constant with another add; recurse.
      const SCEVAddExpr *Add = cast<SCEVAddExpr>(Mul->getOperand(1));
      Interesting |=
        CollectAddOperandsWithScales(M, NewOps, AccumulatedConstant,
                                     Add->op_begin(), Add->getNumOperands(),
                                     NewScale, SE);
    } else {
      // A multiplication of a constant with some other value. Update
      // the map.
      SmallVector<const SCEV *, 4> MulOps(Mul->op_begin()+1, Mul->op_end());
      const SCEV *Key = SE.getMulExpr(MulOps);
      auto Pair = M.insert({Key, NewScale});
      if (Pair.second) {
        NewOps.push_back(Pair.first->first);
      } else {
        Pair.first->second += NewScale;
        // The map already had an entry for this value, which may indicate
        // a folding opportunity.
        Interesting = true;
      }
    }
  } else {
    // An ordinary operand. Update the map.
    std::pair<DenseMap<const SCEV *, APInt>::iterator, bool> Pair =
        M.insert({Ops[i], Scale});
    if (Pair.second) {
      NewOps.push_back(Pair.first->first);
    } else {
      Pair.first->second += Scale;
      // The map already had an entry for this value, which may indicate
      // a folding opportunity.
      Interesting = true;
    }
  }
}

return Interesting;
2202}

2204// We're trying to construct a SCEV of type `Type' with `Ops' as operands and
2205// `OldFlags' as can't-wrap behavior.  Infer a more aggressive set of
2206// can't-overflow flags for the operation if possible.
2207static SCEV::NoWrapFlags
2208StrengthenNoWrapFlags(ScalarEvolution *SE, SCEVTypes Type,
                    const ArrayRef<const SCEV *> Ops,
                    SCEV::NoWrapFlags Flags) {
using namespace std::placeholders;

using OBO = OverflowingBinaryOperator;

bool CanAnalyze =
    Type == scAddExpr || Type == scAddRecExpr || Type == scMulExpr;
(void)CanAnalyze;
assert(CanAnalyze && "don't call from other places!")((CanAnalyze && "don't call from other places!") ? static_cast
<void> (0) : __assert_fail ("CanAnalyze && \"don't call from other places!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2218, __PRETTY_FUNCTION__));

int SignOrUnsignMask = SCEV::FlagNUW | SCEV::FlagNSW;
SCEV::NoWrapFlags SignOrUnsignWrap =
    ScalarEvolution::maskFlags(Flags, SignOrUnsignMask);

// If FlagNSW is true and all the operands are non-negative, infer FlagNUW.
auto IsKnownNonNegative = [&](const SCEV *S) {
  return SE->isKnownNonNegative(S);
};

if (SignOrUnsignWrap == SCEV::FlagNSW && all_of(Ops, IsKnownNonNegative))
  Flags =
      ScalarEvolution::setFlags(Flags, (SCEV::NoWrapFlags)SignOrUnsignMask);

SignOrUnsignWrap = ScalarEvolution::maskFlags(Flags, SignOrUnsignMask);

if (SignOrUnsignWrap != SignOrUnsignMask &&
    (Type == scAddExpr || Type == scMulExpr) && Ops.size() == 2 &&
    isa<SCEVConstant>(Ops[0])) {

  auto Opcode = [&] {
    switch (Type) {
    case scAddExpr:
      return Instruction::Add;
    case scMulExpr:
      return Instruction::Mul;
    default:
      llvm_unreachable("Unexpected SCEV op.")::llvm::llvm_unreachable_internal("Unexpected SCEV op.", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2246);
    }
  }();

  const APInt &C = cast<SCEVConstant>(Ops[0])->getAPInt();

  // (A <opcode> C) --> (A <opcode> C)<nsw> if the op doesn't sign overflow.
  if (!(SignOrUnsignWrap & SCEV::FlagNSW)) {
    auto NSWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
        Opcode, C, OBO::NoSignedWrap);
    if (NSWRegion.contains(SE->getSignedRange(Ops[1])))
      Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNSW);
  }

  // (A <opcode> C) --> (A <opcode> C)<nuw> if the op doesn't unsign overflow.
  if (!(SignOrUnsignWrap & SCEV::FlagNUW)) {
    auto NUWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
        Opcode, C, OBO::NoUnsignedWrap);
    if (NUWRegion.contains(SE->getUnsignedRange(Ops[1])))
      Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW);
  }
}

return Flags;
2270}

2272bool ScalarEvolution::isAvailableAtLoopEntry(const SCEV *S, const Loop *L) {
return isLoopInvariant(S, L) && properlyDominates(S, L->getHeader());
2274}

2276/// Get a canonical add expression, or something simpler if possible.
2277const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
                                      SCEV::NoWrapFlags OrigFlags,
                                      unsigned Depth) {
assert(!(OrigFlags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) &&((!(OrigFlags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) &&
 "only nuw or nsw allowed") ? static_cast<void> (0) : __assert_fail
 ("!(OrigFlags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) && \"only nuw or nsw allowed\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2281, __PRETTY_FUNCTION__))
       "only nuw or nsw allowed")((!(OrigFlags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) &&
 "only nuw or nsw allowed") ? static_cast<void> (0) : __assert_fail
 ("!(OrigFlags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) && \"only nuw or nsw allowed\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2281, __PRETTY_FUNCTION__));
assert(!Ops.empty() && "Cannot get empty add!")((!Ops.empty() && "Cannot get empty add!") ? static_cast
<void> (0) : __assert_fail ("!Ops.empty() && \"Cannot get empty add!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2282, __PRETTY_FUNCTION__));
if (Ops.size() == 1) return Ops[0];
2284#ifndef NDEBUG
Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
  assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&((getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
 "SCEVAddExpr operand types don't match!") ? static_cast<void
> (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVAddExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2288, __PRETTY_FUNCTION__))
         "SCEVAddExpr operand types don't match!")((getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
 "SCEVAddExpr operand types don't match!") ? static_cast<void
> (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVAddExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2288, __PRETTY_FUNCTION__));
2289#endif

// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops, &LI, DT);

// If there are any constants, fold them together.
unsigned Idx = 0;
if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
  ++Idx;
  assert(Idx < Ops.size())((Idx < Ops.size()) ? static_cast<void> (0) : __assert_fail
 ("Idx < Ops.size()", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2298, __PRETTY_FUNCTION__));
  while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
    // We found two constants, fold them together!
    Ops[0] = getConstant(LHSC->getAPInt() + RHSC->getAPInt());
    if (Ops.size() == 2) return Ops[0];
    Ops.erase(Ops.begin()+1);  // Erase the folded element
    LHSC = cast<SCEVConstant>(Ops[0]);
  }

  // If we are left with a constant zero being added, strip it off.
  if (LHSC->getValue()->isZero()) {
    Ops.erase(Ops.begin());
    --Idx;
  }

  if (Ops.size() == 1) return Ops[0];
}

// Delay expensive flag strengthening until necessary.
auto ComputeFlags = [this, OrigFlags](const ArrayRef<const SCEV *> Ops) {
  return StrengthenNoWrapFlags(this, scAddExpr, Ops, OrigFlags);
};

// Limit recursion calls depth.
if (Depth > MaxArithDepth || hasHugeExpression(Ops))
  return getOrCreateAddExpr(Ops, ComputeFlags(Ops));

if (SCEV *S = std::get<0>(findExistingSCEVInCache(scAddExpr, Ops))) {
  // Don't strengthen flags if we have no new information.
  SCEVAddExpr *Add = static_cast<SCEVAddExpr *>(S);
  if (Add->getNoWrapFlags(OrigFlags) != OrigFlags)
    Add->setNoWrapFlags(ComputeFlags(Ops));
  return S;
}

// Okay, check to see if the same value occurs in the operand list more than
// once.  If so, merge them together into an multiply expression.  Since we
// sorted the list, these values are required to be adjacent.
Type *Ty = Ops[0]->getType();
bool FoundMatch = false;
for (unsigned i = 0, e = Ops.size(); i != e-1; ++i)
  if (Ops[i] == Ops[i+1]) {      //  X + Y + Y  -->  X + Y*2
    // Scan ahead to count how many equal operands there are.
    unsigned Count = 2;
    while (i+Count != e && Ops[i+Count] == Ops[i])
      ++Count;
    // Merge the values into a multiply.
    const SCEV *Scale = getConstant(Ty, Count);
    const SCEV *Mul = getMulExpr(Scale, Ops[i], SCEV::FlagAnyWrap, Depth + 1);
    if (Ops.size() == Count)
      return Mul;
    Ops[i] = Mul;
    Ops.erase(Ops.begin()+i+1, Ops.begin()+i+Count);
    --i; e -= Count - 1;
    FoundMatch = true;
  }
if (FoundMatch)
  return getAddExpr(Ops, OrigFlags, Depth + 1);

// Check for truncates. If all the operands are truncated from the same
// type, see if factoring out the truncate would permit the result to be
// folded. eg., n*trunc(x) + m*trunc(y) --> trunc(trunc(m)*x + trunc(n)*y)
// if the contents of the resulting outer trunc fold to something simple.
auto FindTruncSrcType = [&]() -> Type * {
  // We're ultimately looking to fold an addrec of truncs and muls of only
  // constants and truncs, so if we find any other types of SCEV
  // as operands of the addrec then we bail and return nullptr here.
  // Otherwise, we return the type of the operand of a trunc that we find.
  if (auto *T = dyn_cast<SCEVTruncateExpr>(Ops[Idx]))
    return T->getOperand()->getType();
  if (const auto *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) {
    const auto *LastOp = Mul->getOperand(Mul->getNumOperands() - 1);
    if (const auto *T = dyn_cast<SCEVTruncateExpr>(LastOp))
      return T->getOperand()->getType();
  }
  return nullptr;
};
if (auto *SrcType = FindTruncSrcType()) {
  SmallVector<const SCEV *, 8> LargeOps;
  bool Ok = true;
  // Check all the operands to see if they can be represented in the
  // source type of the truncate.
  for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
    if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Ops[i])) {
      if (T->getOperand()->getType() != SrcType) {
        Ok = false;
        break;
      }
      LargeOps.push_back(T->getOperand());
    } else if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
      LargeOps.push_back(getAnyExtendExpr(C, SrcType));
    } else if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(Ops[i])) {
      SmallVector<const SCEV *, 8> LargeMulOps;
      for (unsigned j = 0, f = M->getNumOperands(); j != f && Ok; ++j) {
        if (const SCEVTruncateExpr *T =
              dyn_cast<SCEVTruncateExpr>(M->getOperand(j))) {
          if (T->getOperand()->getType() != SrcType) {
            Ok = false;
            break;
          }
          LargeMulOps.push_back(T->getOperand());
        } else if (const auto *C = dyn_cast<SCEVConstant>(M->getOperand(j))) {
          LargeMulOps.push_back(getAnyExtendExpr(C, SrcType));
        } else {
          Ok = false;
          break;
        }
      }
      if (Ok)
        LargeOps.push_back(getMulExpr(LargeMulOps, SCEV::FlagAnyWrap, Depth + 1));
    } else {
      Ok = false;
      break;
    }
  }
  if (Ok) {
    // Evaluate the expression in the larger type.
    const SCEV *Fold = getAddExpr(LargeOps, SCEV::FlagAnyWrap, Depth + 1);
    // If it folds to something simple, use it. Otherwise, don't.
    if (isa<SCEVConstant>(Fold) || isa<SCEVUnknown>(Fold))
      return getTruncateExpr(Fold, Ty);
  }
}

// Skip past any other cast SCEVs.
while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddExpr)
  ++Idx;

// If there are add operands they would be next.
if (Idx < Ops.size()) {
  bool DeletedAdd = false;
  while (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[Idx])) {
    if (Ops.size() > AddOpsInlineThreshold ||
        Add->getNumOperands() > AddOpsInlineThreshold)
      break;
    // If we have an add, expand the add operands onto the end of the operands
    // list.
    Ops.erase(Ops.begin()+Idx);
    Ops.append(Add->op_begin(), Add->op_end());
    DeletedAdd = true;
  }

  // If we deleted at least one add, we added operands to the end of the list,
  // and they are not necessarily sorted.  Recurse to resort and resimplify
  // any operands we just acquired.
  if (DeletedAdd)
    return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
}

// Skip over the add expression until we get to a multiply.
while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scMulExpr)
  ++Idx;

// Check to see if there are any folding opportunities present with
// operands multiplied by constant values.
if (Idx < Ops.size() && isa<SCEVMulExpr>(Ops[Idx])) {
  uint64_t BitWidth = getTypeSizeInBits(Ty);
  DenseMap<const SCEV *, APInt> M;
  SmallVector<const SCEV *, 8> NewOps;
  APInt AccumulatedConstant(BitWidth, 0);
  if (CollectAddOperandsWithScales(M, NewOps, AccumulatedConstant,
                                   Ops.data(), Ops.size(),
                                   APInt(BitWidth, 1), *this)) {
    struct APIntCompare {
      bool operator()(const APInt &LHS, const APInt &RHS) const {
        return LHS.ult(RHS);
      }
    };

    // Some interesting folding opportunity is present, so its worthwhile to
    // re-generate the operands list. Group the operands by constant scale,
    // to avoid multiplying by the same constant scale multiple times.
    std::map<APInt, SmallVector<const SCEV *, 4>, APIntCompare> MulOpLists;
    for (const SCEV *NewOp : NewOps)
      MulOpLists[M.find(NewOp)->second].push_back(NewOp);
    // Re-generate the operands list.
    Ops.clear();
    if (AccumulatedConstant != 0)
      Ops.push_back(getConstant(AccumulatedConstant));
    for (auto &MulOp : MulOpLists)
      if (MulOp.first != 0)
        Ops.push_back(getMulExpr(
            getConstant(MulOp.first),
            getAddExpr(MulOp.second, SCEV::FlagAnyWrap, Depth + 1),
            SCEV::FlagAnyWrap, Depth + 1));
    if (Ops.empty())
      return getZero(Ty);
    if (Ops.size() == 1)
      return Ops[0];
    return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
  }
}

// If we are adding something to a multiply expression, make sure the
// something is not already an operand of the multiply.  If so, merge it into
// the multiply.
for (; Idx < Ops.size() && isa<SCEVMulExpr>(Ops[Idx]); ++Idx) {
  const SCEVMulExpr *Mul = cast<SCEVMulExpr>(Ops[Idx]);
  for (unsigned MulOp = 0, e = Mul->getNumOperands(); MulOp != e; ++MulOp) {
    const SCEV *MulOpSCEV = Mul->getOperand(MulOp);
    if (isa<SCEVConstant>(MulOpSCEV))
      continue;
    for (unsigned AddOp = 0, e = Ops.size(); AddOp != e; ++AddOp)
      if (MulOpSCEV == Ops[AddOp]) {
        // Fold W + X + (X * Y * Z)  -->  W + (X * ((Y*Z)+1))
        const SCEV *InnerMul = Mul->getOperand(MulOp == 0);
        if (Mul->getNumOperands() != 2) {
          // If the multiply has more than two operands, we must get the
          // Y*Z term.
          SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(),
                                              Mul->op_begin()+MulOp);
          MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end());
          InnerMul = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1);
        }
        SmallVector<const SCEV *, 2> TwoOps = {getOne(Ty), InnerMul};
        const SCEV *AddOne = getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1);
        const SCEV *OuterMul = getMulExpr(AddOne, MulOpSCEV,
                                          SCEV::FlagAnyWrap, Depth + 1);
        if (Ops.size() == 2) return OuterMul;
        if (AddOp < Idx) {
          Ops.erase(Ops.begin()+AddOp);
          Ops.erase(Ops.begin()+Idx-1);
        } else {
          Ops.erase(Ops.begin()+Idx);
          Ops.erase(Ops.begin()+AddOp-1);
        }
        Ops.push_back(OuterMul);
        return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
      }

    // Check this multiply against other multiplies being added together.
    for (unsigned OtherMulIdx = Idx+1;
         OtherMulIdx < Ops.size() && isa<SCEVMulExpr>(Ops[OtherMulIdx]);
         ++OtherMulIdx) {
      const SCEVMulExpr *OtherMul = cast<SCEVMulExpr>(Ops[OtherMulIdx]);
      // If MulOp occurs in OtherMul, we can fold the two multiplies
      // together.
      for (unsigned OMulOp = 0, e = OtherMul->getNumOperands();
           OMulOp != e; ++OMulOp)
        if (OtherMul->getOperand(OMulOp) == MulOpSCEV) {
          // Fold X + (A*B*C) + (A*D*E) --> X + (A*(B*C+D*E))
          const SCEV *InnerMul1 = Mul->getOperand(MulOp == 0);
          if (Mul->getNumOperands() != 2) {
            SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(),
                                                Mul->op_begin()+MulOp);
            MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end());
            InnerMul1 = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1);
          }
          const SCEV *InnerMul2 = OtherMul->getOperand(OMulOp == 0);
          if (OtherMul->getNumOperands() != 2) {
            SmallVector<const SCEV *, 4> MulOps(OtherMul->op_begin(),
                                                OtherMul->op_begin()+OMulOp);
            MulOps.append(OtherMul->op_begin()+OMulOp+1, OtherMul->op_end());
            InnerMul2 = getMulExpr(MulOps, SCEV::FlagAnyWrap, Depth + 1);
          }
          SmallVector<const SCEV *, 2> TwoOps = {InnerMul1, InnerMul2};
          const SCEV *InnerMulSum =
              getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1);
          const SCEV *OuterMul = getMulExpr(MulOpSCEV, InnerMulSum,
                                            SCEV::FlagAnyWrap, Depth + 1);
          if (Ops.size() == 2) return OuterMul;
          Ops.erase(Ops.begin()+Idx);
          Ops.erase(Ops.begin()+OtherMulIdx-1);
          Ops.push_back(OuterMul);
          return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
        }
    }
  }
}

// If there are any add recurrences in the operands list, see if any other
// added values are loop invariant.  If so, we can fold them into the
// recurrence.
while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddRecExpr)
  ++Idx;

// Scan over all recurrences, trying to fold loop invariants into them.
for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) {
  // Scan all of the other operands to this add and add them to the vector if
  // they are loop invariant w.r.t. the recurrence.
  SmallVector<const SCEV *, 8> LIOps;
  const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
  const Loop *AddRecLoop = AddRec->getLoop();
  for (unsigned i = 0, e = Ops.size(); i != e; ++i)
    if (isAvailableAtLoopEntry(Ops[i], AddRecLoop)) {
      LIOps.push_back(Ops[i]);
      Ops.erase(Ops.begin()+i);
      --i; --e;
    }

  // If we found some loop invariants, fold them into the recurrence.
  if (!LIOps.empty()) {
    // Compute nowrap flags for the addition of the loop-invariant ops and
    // the addrec. Temporarily push it as an operand for that purpose.
    LIOps.push_back(AddRec);
    SCEV::NoWrapFlags Flags = ComputeFlags(LIOps);
    LIOps.pop_back();

    //  NLI + LI + {Start,+,Step}  -->  NLI + {LI+Start,+,Step}
    LIOps.push_back(AddRec->getStart());

    SmallVector<const SCEV *, 4> AddRecOps(AddRec->op_begin(),
                                           AddRec->op_end());
    // This follows from the fact that the no-wrap flags on the outer add
    // expression are applicable on the 0th iteration, when the add recurrence
    // will be equal to its start value.
    AddRecOps[0] = getAddExpr(LIOps, Flags, Depth + 1);

    // Build the new addrec. Propagate the NUW and NSW flags if both the
    // outer add and the inner addrec are guaranteed to have no overflow.
    // Always propagate NW.
    Flags = AddRec->getNoWrapFlags(setFlags(Flags, SCEV::FlagNW));
    const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop, Flags);

    // If all of the other operands were loop invariant, we are done.
    if (Ops.size() == 1) return NewRec;

    // Otherwise, add the folded AddRec by the non-invariant parts.
    for (unsigned i = 0;; ++i)
      if (Ops[i] == AddRec) {
        Ops[i] = NewRec;
        break;
      }
    return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
  }

  // Okay, if there weren't any loop invariants to be folded, check to see if
  // there are multiple AddRec's with the same loop induction variable being
  // added together.  If so, we can fold them.
  for (unsigned OtherIdx = Idx+1;
       OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
       ++OtherIdx) {
    // We expect the AddRecExpr's to be sorted in reverse dominance order,
    // so that the 1st found AddRecExpr is dominated by all others.
    assert(DT.dominates(((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->
getLoop()->getHeader(), AddRec->getLoop()->getHeader
()) && "AddRecExprs are not sorted in reverse dominance order?"
) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2635, __PRETTY_FUNCTION__))
         cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(),((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->
getLoop()->getHeader(), AddRec->getLoop()->getHeader
()) && "AddRecExprs are not sorted in reverse dominance order?"
) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2635, __PRETTY_FUNCTION__))
         AddRec->getLoop()->getHeader()) &&((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->
getLoop()->getHeader(), AddRec->getLoop()->getHeader
()) && "AddRecExprs are not sorted in reverse dominance order?"
) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2635, __PRETTY_FUNCTION__))
      "AddRecExprs are not sorted in reverse dominance order?")((DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->
getLoop()->getHeader(), AddRec->getLoop()->getHeader
()) && "AddRecExprs are not sorted in reverse dominance order?"
) ? static_cast<void> (0) : __assert_fail ("DT.dominates( cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()->getHeader(), AddRec->getLoop()->getHeader()) && \"AddRecExprs are not sorted in reverse dominance order?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2635, __PRETTY_FUNCTION__));
    if (AddRecLoop == cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()) {
      // Other + {A,+,B}<L> + {C,+,D}<L>  -->  Other + {A+C,+,B+D}<L>
      SmallVector<const SCEV *, 4> AddRecOps(AddRec->op_begin(),
                                             AddRec->op_end());
      for (; OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
           ++OtherIdx) {
        const auto *OtherAddRec = cast<SCEVAddRecExpr>(Ops[OtherIdx]);
        if (OtherAddRec->getLoop() == AddRecLoop) {
          for (unsigned i = 0, e = OtherAddRec->getNumOperands();
               i != e; ++i) {
            if (i >= AddRecOps.size()) {
              AddRecOps.append(OtherAddRec->op_begin()+i,
                               OtherAddRec->op_end());
              break;
            }
            SmallVector<const SCEV *, 2> TwoOps = {
                AddRecOps[i], OtherAddRec->getOperand(i)};
            AddRecOps[i] = getAddExpr(TwoOps, SCEV::FlagAnyWrap, Depth + 1);
          }
          Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
        }
      }
      // Step size has changed, so we cannot guarantee no self-wraparound.
      Ops[Idx] = getAddRecExpr(AddRecOps, AddRecLoop, SCEV::FlagAnyWrap);
      return getAddExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
    }
  }

  // Otherwise couldn't fold anything into this recurrence.  Move onto the
  // next one.
}

// Okay, it looks like we really DO need an add expr.  Check to see if we
// already have one, otherwise create a new one.
return getOrCreateAddExpr(Ops, ComputeFlags(Ops));
2671}

2673const SCEV *
2674ScalarEvolution::getOrCreateAddExpr(ArrayRef<const SCEV *> Ops,
                                  SCEV::NoWrapFlags Flags) {
FoldingSetNodeID ID;
ID.AddInteger(scAddExpr);
for (const SCEV *Op : Ops)
  ID.AddPointer(Op);
void *IP = nullptr;
SCEVAddExpr *S =
    static_cast<SCEVAddExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
if (!S) {
  const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
  std::uninitialized_copy(Ops.begin(), Ops.end(), O);
  S = new (SCEVAllocator)
      SCEVAddExpr(ID.Intern(SCEVAllocator), O, Ops.size());
  UniqueSCEVs.InsertNode(S, IP);
  addToLoopUseLists(S);
}
S->setNoWrapFlags(Flags);
return S;
2693}

2695const SCEV *
2696ScalarEvolution::getOrCreateAddRecExpr(ArrayRef<const SCEV *> Ops,
                                     const Loop *L, SCEV::NoWrapFlags Flags) {
FoldingSetNodeID ID;
ID.AddInteger(scAddRecExpr);
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
  ID.AddPointer(Ops[i]);
ID.AddPointer(L);
void *IP = nullptr;
SCEVAddRecExpr *S =
    static_cast<SCEVAddRecExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
if (!S) {
  const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
  std::uninitialized_copy(Ops.begin(), Ops.end(), O);
  S = new (SCEVAllocator)
      SCEVAddRecExpr(ID.Intern(SCEVAllocator), O, Ops.size(), L);
  UniqueSCEVs.InsertNode(S, IP);
  addToLoopUseLists(S);
}
setNoWrapFlags(S, Flags);
return S;
2716}

2718const SCEV *
2719ScalarEvolution::getOrCreateMulExpr(ArrayRef<const SCEV *> Ops,
                                  SCEV::NoWrapFlags Flags) {
FoldingSetNodeID ID;
ID.AddInteger(scMulExpr);
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
  ID.AddPointer(Ops[i]);
void *IP = nullptr;
SCEVMulExpr *S =
  static_cast<SCEVMulExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
if (!S) {
  const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
  std::uninitialized_copy(Ops.begin(), Ops.end(), O);
  S = new (SCEVAllocator) SCEVMulExpr(ID.Intern(SCEVAllocator),
                                      O, Ops.size());
  UniqueSCEVs.InsertNode(S, IP);
  addToLoopUseLists(S);
}
S->setNoWrapFlags(Flags);
return S;
2738}

2740static uint64_t umul_ov(uint64_t i, uint64_t j, bool &Overflow) {
uint64_t k = i*j;
if (j > 1 && k / j != i) Overflow = true;
return k;
2744}

2746/// Compute the result of "n choose k", the binomial coefficient.  If an
2747/// intermediate computation overflows, Overflow will be set and the return will
2748/// be garbage. Overflow is not cleared on absence of overflow.
2749static uint64_t Choose(uint64_t n, uint64_t k, bool &Overflow) {
// We use the multiplicative formula:
//     n(n-1)(n-2)...(n-(k-1)) / k(k-1)(k-2)...1 .
// At each iteration, we take the n-th term of the numeral and divide by the
// (k-n)th term of the denominator.  This division will always produce an
// integral result, and helps reduce the chance of overflow in the
// intermediate computations. However, we can still overflow even when the
// final result would fit.

if (n == 0 || n == k) return 1;
if (k > n) return 0;

if (k > n/2)
  k = n-k;

uint64_t r = 1;
for (uint64_t i = 1; i <= k; ++i) {
  r = umul_ov(r, n-(i-1), Overflow);
  r /= i;
}
return r;
2770}

2772/// Determine if any of the operands in this SCEV are a constant or if
2773/// any of the add or multiply expressions in this SCEV contain a constant.
2774static bool containsConstantInAddMulChain(const SCEV *StartExpr) {
struct FindConstantInAddMulChain {
  bool FoundConstant = false;

  bool follow(const SCEV *S) {
    FoundConstant |= isa<SCEVConstant>(S);
    return isa<SCEVAddExpr>(S) || isa<SCEVMulExpr>(S);
  }

  bool isDone() const {
    return FoundConstant;
  }
};

FindConstantInAddMulChain F;
SCEVTraversal<FindConstantInAddMulChain> ST(F);
ST.visitAll(StartExpr);
return F.FoundConstant;
2792}

2794/// Get a canonical multiply expression, or something simpler if possible.
2795const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
                                      SCEV::NoWrapFlags OrigFlags,
                                      unsigned Depth) {
assert(OrigFlags == maskFlags(OrigFlags, SCEV::FlagNUW | SCEV::FlagNSW) &&((OrigFlags == maskFlags(OrigFlags, SCEV::FlagNUW | SCEV::FlagNSW
) && "only nuw or nsw allowed") ? static_cast<void
> (0) : __assert_fail ("OrigFlags == maskFlags(OrigFlags, SCEV::FlagNUW | SCEV::FlagNSW) && \"only nuw or nsw allowed\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2799, __PRETTY_FUNCTION__))
       "only nuw or nsw allowed")((OrigFlags == maskFlags(OrigFlags, SCEV::FlagNUW | SCEV::FlagNSW
) && "only nuw or nsw allowed") ? static_cast<void
> (0) : __assert_fail ("OrigFlags == maskFlags(OrigFlags, SCEV::FlagNUW | SCEV::FlagNSW) && \"only nuw or nsw allowed\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2799, __PRETTY_FUNCTION__));
assert(!Ops.empty() && "Cannot get empty mul!")((!Ops.empty() && "Cannot get empty mul!") ? static_cast
<void> (0) : __assert_fail ("!Ops.empty() && \"Cannot get empty mul!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2800, __PRETTY_FUNCTION__));
if (Ops.size() == 1) return Ops[0];
2802#ifndef NDEBUG
Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
  assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&((getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
 "SCEVMulExpr operand types don't match!") ? static_cast<void
> (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVMulExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2806, __PRETTY_FUNCTION__))
         "SCEVMulExpr operand types don't match!")((getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
 "SCEVMulExpr operand types don't match!") ? static_cast<void
> (0) : __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"SCEVMulExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2806, __PRETTY_FUNCTION__));
2807#endif

// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops, &LI, DT);

// If there are any constants, fold them together.
unsigned Idx = 0;
if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
  ++Idx;
  assert(Idx < Ops.size())((Idx < Ops.size()) ? static_cast<void> (0) : __assert_fail
 ("Idx < Ops.size()", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 2816, __PRETTY_FUNCTION__));
  while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
    // We found two constants, fold them together!
    Ops[0] = getConstant(LHSC->getAPInt() * RHSC->getAPInt());
    if (Ops.size() == 2) return Ops[0];
    Ops.erase(Ops.begin()+1);  // Erase the folded element
    LHSC = cast<SCEVConstant>(Ops[0]);
  }

  // If we have a multiply of zero, it will always be zero.
  if (LHSC->getValue()->isZero())
    return LHSC;

  // If we are left with a constant one being multiplied, strip it off.
  if (LHSC->getValue()->isOne()) {
    Ops.erase(Ops.begin());
    --Idx;
  }

  if (Ops.size() == 1)
    return Ops[0];
}

// Delay expensive flag strengthening until necessary.
auto ComputeFlags = [this, OrigFlags](const ArrayRef<const SCEV *> Ops) {
  return StrengthenNoWrapFlags(this, scMulExpr, Ops, OrigFlags);
};

// Limit recursion calls depth.
if (Depth > MaxArithDepth || hasHugeExpression(Ops))
  return getOrCreateMulExpr(Ops, ComputeFlags(Ops));

if (SCEV *S = std::get<0>(findExistingSCEVInCache(scMulExpr, Ops))) {
  // Don't strengthen flags if we have no new information.
  SCEVMulExpr *Mul = static_cast<SCEVMulExpr *>(S);
  if (Mul->getNoWrapFlags(OrigFlags) != OrigFlags)
    Mul->setNoWrapFlags(ComputeFlags(Ops));
  return S;
}

if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
  if (Ops.size() == 2) {
    // C1*(C2+V) -> C1*C2 + C1*V
    if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1]))
      // If any of Add's ops are Adds or Muls with a constant, apply this
      // transformation as well.
      //
      // TODO: There are some cases where this transformation is not
      // profitable; for example, Add = (C0 + X) * Y + Z.  Maybe the scope of
      // this transformation should be narrowed down.
      if (Add->getNumOperands() == 2 && containsConstantInAddMulChain(Add))
        return getAddExpr(getMulExpr(LHSC, Add->getOperand(0),
                                     SCEV::FlagAnyWrap, Depth + 1),
                          getMulExpr(LHSC, Add->getOperand(1),
                                     SCEV::FlagAnyWrap, Depth + 1),
                          SCEV::FlagAnyWrap, Depth + 1);

    if (Ops[0]->isAllOnesValue()) {
      // If we have a mul by -1 of an add, try distributing the -1 among the
      // add operands.
      if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1])) {
        SmallVector<const SCEV *, 4> NewOps;
        bool AnyFolded = false;
        for (const SCEV *AddOp : Add->operands()) {
          const SCEV *Mul = getMulExpr(Ops[0], AddOp, SCEV::FlagAnyWrap,
                                       Depth + 1);
          if (!isa<SCEVMulExpr>(Mul)) AnyFolded = true;
          NewOps.push_back(Mul);
        }
        if (AnyFolded)
          return getAddExpr(NewOps, SCEV::FlagAnyWrap, Depth + 1);
      } else if (const auto *AddRec = dyn_cast<SCEVAddRecExpr>(Ops[1])) {
        // Negation preserves a recurrence's no self-wrap property.
        SmallVector<const SCEV *, 4> Operands;
        for (const SCEV *AddRecOp : AddRec->operands())
          Operands.push_back(getMulExpr(Ops[0], AddRecOp, SCEV::FlagAnyWrap,
                                        Depth + 1));

        return getAddRecExpr(Operands, AddRec->getLoop(),
                             AddRec->getNoWrapFlags(SCEV::FlagNW));
      }
    }
  }
}

// Skip over the add expression until we get to a multiply.
while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scMulExpr)
  ++Idx;

// If there are mul operands inline them all into this expression.
if (Idx < Ops.size()) {
  bool DeletedMul = false;
  while (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[Idx])) {
    if (Ops.size() > MulOpsInlineThreshold)
      break;
    // If we have an mul, expand the mul operands onto the end of the
    // operands list.
    Ops.erase(Ops.begin()+Idx);
    Ops.append(Mul->op_begin(), Mul->op_end());
    DeletedMul = true;
  }

  // If we deleted at least one mul, we added operands to the end of the
  // list, and they are not necessarily sorted.  Recurse to resort and
  // resimplify any operands we just acquired.
  if (DeletedMul)
    return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
}

// If there are any add recurrences in the operands list, see if any other
// added values are loop invariant.  If so, we can fold them into the
// recurrence.
while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < scAddRecExpr)
  ++Idx;

// Scan over all recurrences, trying to fold loop invariants into them.
for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) {
  // Scan all of the other operands to this mul and add them to the vector
  // if they are loop invariant w.r.t. the recurrence.
  SmallVector<const SCEV *, 8> LIOps;
  const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
  const Loop *AddRecLoop = AddRec->getLoop();
  for (unsigned i = 0, e = Ops.size(); i != e; ++i)
    if (isAvailableAtLoopEntry(Ops[i], AddRecLoop)) {
      LIOps.push_back(Ops[i]);
      Ops.erase(Ops.begin()+i);
      --i; --e;
    }

  // If we found some loop invariants, fold them into the recurrence.
  if (!LIOps.empty()) {
    //  NLI * LI * {Start,+,Step}  -->  NLI * {LI*Start,+,LI*Step}
    SmallVector<const SCEV *, 4> NewOps;
    NewOps.reserve(AddRec->getNumOperands());
    const SCEV *Scale = getMulExpr(LIOps, SCEV::FlagAnyWrap, Depth + 1);
    for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i)
      NewOps.push_back(getMulExpr(Scale, AddRec->getOperand(i),
                                  SCEV::FlagAnyWrap, Depth + 1));

    // Build the new addrec. Propagate the NUW and NSW flags if both the
    // outer mul and the inner addrec are guaranteed to have no overflow.
    //
    // No self-wrap cannot be guaranteed after changing the step size, but
    // will be inferred if either NUW or NSW is true.
    SCEV::NoWrapFlags Flags = ComputeFlags({Scale, AddRec});
    const SCEV *NewRec = getAddRecExpr(
        NewOps, AddRecLoop, AddRec->getNoWrapFlags(Flags));

    // If all of the other operands were loop invariant, we are done.
    if (Ops.size() == 1) return NewRec;

    // Otherwise, multiply the folded AddRec by the non-invariant parts.
    for (unsigned i = 0;; ++i)
      if (Ops[i] == AddRec) {
        Ops[i] = NewRec;
        break;
      }
    return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);
  }

  // Okay, if there weren't any loop invariants to be folded, check to see
  // if there are multiple AddRec's with the same loop induction variable
  // being multiplied together.  If so, we can fold them.

  // {A1,+,A2,+,...,+,An}<L> * {B1,+,B2,+,...,+,Bn}<L>
  // = {x=1 in [ sum y=x..2x [ sum z=max(y-x, y-n)..min(x,n) [
  //       choose(x, 2x)*choose(2x-y, x-z)*A_{y-z}*B_z
  //   ]]],+,...up to x=2n}.
  // Note that the arguments to choose() are always integers with values
  // known at compile time, never SCEV objects.
  //
  // The implementation avoids pointless extra computations when the two
  // addrec's are of different length (mathematically, it's equivalent to
  // an infinite stream of zeros on the right).
  bool OpsModified = false;
  for (unsigned OtherIdx = Idx+1;
       OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
       ++OtherIdx) {
    const SCEVAddRecExpr *OtherAddRec =
      dyn_cast<SCEVAddRecExpr>(Ops[OtherIdx]);
    if (!OtherAddRec || OtherAddRec->getLoop() != AddRecLoop)
      continue;

    // Limit max number of arguments to avoid creation of unreasonably big
    // SCEVAddRecs with very complex operands.
    if (AddRec->getNumOperands() + OtherAddRec->getNumOperands() - 1 >
        MaxAddRecSize || hasHugeExpression({AddRec, OtherAddRec}))
      continue;

    bool Overflow = false;
    Type *Ty = AddRec->getType();
    bool LargerThan64Bits = getTypeSizeInBits(Ty) > 64;
    SmallVector<const SCEV*, 7> AddRecOps;
    for (int x = 0, xe = AddRec->getNumOperands() +
           OtherAddRec->getNumOperands() - 1; x != xe && !Overflow; ++x) {
      SmallVector <const SCEV *, 7> SumOps;
      for (int y = x, ye = 2*x+1; y != ye && !Overflow; ++y) {
        uint64_t Coeff1 = Choose(x, 2*x - y, Overflow);
        for (int z = std::max(y-x, y-(int)AddRec->getNumOperands()+1),
               ze = std::min(x+1, (int)OtherAddRec->getNumOperands());
             z < ze && !Overflow; ++z) {
          uint64_t Coeff2 = Choose(2*x - y, x-z, Overflow);
          uint64_t Coeff;
          if (LargerThan64Bits)
            Coeff = umul_ov(Coeff1, Coeff2, Overflow);
          else
            Coeff = Coeff1*Coeff2;
          const SCEV *CoeffTerm = getConstant(Ty, Coeff);
          const SCEV *Term1 = AddRec->getOperand(y-z);
          const SCEV *Term2 = OtherAddRec->getOperand(z);
          SumOps.push_back(getMulExpr(CoeffTerm, Term1, Term2,
                                      SCEV::FlagAnyWrap, Depth + 1));
        }
      }
      if (SumOps.empty())
        SumOps.push_back(getZero(Ty));
      AddRecOps.push_back(getAddExpr(SumOps, SCEV::FlagAnyWrap, Depth + 1));
    }
    if (!Overflow) {
      const SCEV *NewAddRec = getAddRecExpr(AddRecOps, AddRecLoop,
                                            SCEV::FlagAnyWrap);
      if (Ops.size() == 2) return NewAddRec;
      Ops[Idx] = NewAddRec;
      Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
      OpsModified = true;
      AddRec = dyn_cast<SCEVAddRecExpr>(NewAddRec);
      if (!AddRec)
        break;
    }
  }
  if (OpsModified)
    return getMulExpr(Ops, SCEV::FlagAnyWrap, Depth + 1);

  // Otherwise couldn't fold anything into this recurrence.  Move onto the
  // next one.
}

// Okay, it looks like we really DO need an mul expr.  Check to see if we
// already have one, otherwise create a new one.
return getOrCreateMulExpr(Ops, ComputeFlags(Ops));
3056}

3058/// Represents an unsigned remainder expression based on unsigned division.
3059const SCEV *ScalarEvolution::getURemExpr(const SCEV *LHS,
                                       const SCEV *RHS) {
assert(getEffectiveSCEVType(LHS->getType()) ==((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType
(RHS->getType()) && "SCEVURemExpr operand types don't match!"
) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVURemExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3063, __PRETTY_FUNCTION__))
       getEffectiveSCEVType(RHS->getType()) &&((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType
(RHS->getType()) && "SCEVURemExpr operand types don't match!"
) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVURemExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3063, __PRETTY_FUNCTION__))
       "SCEVURemExpr operand types don't match!")((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType
(RHS->getType()) && "SCEVURemExpr operand types don't match!"
) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVURemExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3063, __PRETTY_FUNCTION__));

// Short-circuit easy cases
if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
  // If constant is one, the result is trivial
  if (RHSC->getValue()->isOne())
    return getZero(LHS->getType()); // X urem 1 --> 0

  // If constant is a power of two, fold into a zext(trunc(LHS)).
  if (RHSC->getAPInt().isPowerOf2()) {
    Type *FullTy = LHS->getType();
    Type *TruncTy =
        IntegerType::get(getContext(), RHSC->getAPInt().logBase2());
    return getZeroExtendExpr(getTruncateExpr(LHS, TruncTy), FullTy);
  }
}

// Fallback to %a == %x urem %y == %x -<nuw> ((%x udiv %y) *<nuw> %y)
const SCEV *UDiv = getUDivExpr(LHS, RHS);
const SCEV *Mult = getMulExpr(UDiv, RHS, SCEV::FlagNUW);
return getMinusSCEV(LHS, Mult, SCEV::FlagNUW);
3084}

3086/// Get a canonical unsigned division expression, or something simpler if
3087/// possible.
3088const SCEV *ScalarEvolution::getUDivExpr(const SCEV *LHS,
                                       const SCEV *RHS) {
assert(getEffectiveSCEVType(LHS->getType()) ==((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType
(RHS->getType()) && "SCEVUDivExpr operand types don't match!"
) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVUDivExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3092, __PRETTY_FUNCTION__))
       getEffectiveSCEVType(RHS->getType()) &&((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType
(RHS->getType()) && "SCEVUDivExpr operand types don't match!"
) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVUDivExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3092, __PRETTY_FUNCTION__))
       "SCEVUDivExpr operand types don't match!")((getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType
(RHS->getType()) && "SCEVUDivExpr operand types don't match!"
) ? static_cast<void> (0) : __assert_fail ("getEffectiveSCEVType(LHS->getType()) == getEffectiveSCEVType(RHS->getType()) && \"SCEVUDivExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3092, __PRETTY_FUNCTION__));

FoldingSetNodeID ID;
ID.AddInteger(scUDivExpr);
ID.AddPointer(LHS);
ID.AddPointer(RHS);
void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP))
  return S;

if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
  if (RHSC->getValue()->isOne())
    return LHS;                               // X udiv 1 --> x
  // If the denominator is zero, the result of the udiv is undefined. Don't
  // try to analyze it, because the resolution chosen here may differ from
  // the resolution chosen in other parts of the compiler.
  if (!RHSC->getValue()->isZero()) {
    // Determine if the division can be folded into the operands of
    // its operands.
    // TODO: Generalize this to non-constants by using known-bits information.
    Type *Ty = LHS->getType();
    unsigned LZ = RHSC->getAPInt().countLeadingZeros();
    unsigned MaxShiftAmt = getTypeSizeInBits(Ty) - LZ - 1;
    // For non-power-of-two values, effectively round the value up to the
    // nearest power of two.
    if (!RHSC->getAPInt().isPowerOf2())
      ++MaxShiftAmt;
    IntegerType *ExtTy =
      IntegerType::get(getContext(), getTypeSizeInBits(Ty) + MaxShiftAmt);
    if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(LHS))
      if (const SCEVConstant *Step =
          dyn_cast<SCEVConstant>(AR->getStepRecurrence(*this))) {
        // {X,+,N}/C --> {X/C,+,N/C} if safe and N/C can be folded.
        const APInt &StepInt = Step->getAPInt();
        const APInt &DivInt = RHSC->getAPInt();
        if (!StepInt.urem(DivInt) &&
            getZeroExtendExpr(AR, ExtTy) ==
            getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy),
                          getZeroExtendExpr(Step, ExtTy),
                          AR->getLoop(), SCEV::FlagAnyWrap)) {
          SmallVector<const SCEV *, 4> Operands;
          for (const SCEV *Op : AR->operands())
            Operands.push_back(getUDivExpr(Op, RHS));
          return getAddRecExpr(Operands, AR->getLoop(), SCEV::FlagNW);
        }
        /// Get a canonical UDivExpr for a recurrence.
        /// {X,+,N}/C => {Y,+,N}/C where Y=X-(X%N). Safe when C%N=0.
        // We can currently only fold X%N if X is constant.
        const SCEVConstant *StartC = dyn_cast<SCEVConstant>(AR->getStart());
        if (StartC && !DivInt.urem(StepInt) &&
            getZeroExtendExpr(AR, ExtTy) ==
            getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy),
                          getZeroExtendExpr(Step, ExtTy),
                          AR->getLoop(), SCEV::FlagAnyWrap)) {
          const APInt &StartInt = StartC->getAPInt();
          const APInt &StartRem = StartInt.urem(StepInt);
          if (StartRem != 0) {
            const SCEV *NewLHS =
                getAddRecExpr(getConstant(StartInt - StartRem), Step,
                              AR->getLoop(), SCEV::FlagNW);
            if (LHS != NewLHS) {
              LHS = NewLHS;

              // Reset the ID to include the new LHS, and check if it is
              // already cached.
              ID.clear();
              ID.AddInteger(scUDivExpr);
              ID.AddPointer(LHS);
              ID.AddPointer(RHS);
              IP = nullptr;
              if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP))
                return S;
            }
          }
        }
      }
    // (A*B)/C --> A*(B/C) if safe and B/C can be folded.
    if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(LHS)) {
      SmallVector<const SCEV *, 4> Operands;
      for (const SCEV *Op : M->operands())
        Operands.push_back(getZeroExtendExpr(Op, ExtTy));
      if (getZeroExtendExpr(M, ExtTy) == getMulExpr(Operands))
        // Find an operand that's safely divisible.
        for (unsigned i = 0, e = M->getNumOperands(); i != e; ++i) {
          const SCEV *Op = M->getOperand(i);
          const SCEV *Div = getUDivExpr(Op, RHSC);
          if (!isa<SCEVUDivExpr>(Div) && getMulExpr(Div, RHSC) == Op) {
            Operands = SmallVector<const SCEV *, 4>(M->op_begin(),
                                                    M->op_end());
            Operands[i] = Div;
            return getMulExpr(Operands);
          }
        }
    }

    // (A/B)/C --> A/(B*C) if safe and B*C can be folded.
    if (const SCEVUDivExpr *OtherDiv = dyn_cast<SCEVUDivExpr>(LHS)) {
      if (auto *DivisorConstant =
              dyn_cast<SCEVConstant>(OtherDiv->getRHS())) {
        bool Overflow = false;
        APInt NewRHS =
            DivisorConstant->getAPInt().umul_ov(RHSC->getAPInt(), Overflow);
        if (Overflow) {
          return getConstant(RHSC->getType(), 0, false);
        }
        return getUDivExpr(OtherDiv->getLHS(), getConstant(NewRHS));
      }
    }

    // (A+B)/C --> (A/C + B/C) if safe and A/C and B/C can be folded.
    if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(LHS)) {
      SmallVector<const SCEV *, 4> Operands;
      for (const SCEV *Op : A->operands())
        Operands.push_back(getZeroExtendExpr(Op, ExtTy));
      if (getZeroExtendExpr(A, ExtTy) == getAddExpr(Operands)) {
        Operands.clear();
        for (unsigned i = 0, e = A->getNumOperands(); i != e; ++i) {
          const SCEV *Op = getUDivExpr(A->getOperand(i), RHS);
          if (isa<SCEVUDivExpr>(Op) ||
              getMulExpr(Op, RHS) != A->getOperand(i))
            break;
          Operands.push_back(Op);
        }
        if (Operands.size() == A->getNumOperands())
          return getAddExpr(Operands);
      }
    }

    // Fold if both operands are constant.
    if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
      Constant *LHSCV = LHSC->getValue();
      Constant *RHSCV = RHSC->getValue();
      return getConstant(cast<ConstantInt>(ConstantExpr::getUDiv(LHSCV,
                                                                 RHSCV)));
    }
  }
}

// The Insertion Point (IP) might be invalid by now (due to UniqueSCEVs
// changes). Make sure we get a new one.
IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
SCEV *S = new (SCEVAllocator) SCEVUDivExpr(ID.Intern(SCEVAllocator),
                                           LHS, RHS);
UniqueSCEVs.InsertNode(S, IP);
addToLoopUseLists(S);
return S;
3239}

3241static const APInt gcd(const SCEVConstant *C1, const SCEVConstant *C2) {
APInt A = C1->getAPInt().abs();
APInt B = C2->getAPInt().abs();
uint32_t ABW = A.getBitWidth();
uint32_t BBW = B.getBitWidth();

if (ABW > BBW)
  B = B.zext(ABW);
else if (ABW < BBW)
  A = A.zext(BBW);

return APIntOps::GreatestCommonDivisor(std::move(A), std::move(B));
3253}

3255/// Get a canonical unsigned division expression, or something simpler if
3256/// possible. There is no representation for an exact udiv in SCEV IR, but we
3257/// can attempt to remove factors from the LHS and RHS.  We can't do this when
3258/// it's not exact because the udiv may be clearing bits.
3259const SCEV *ScalarEvolution::getUDivExactExpr(const SCEV *LHS,
                                            const SCEV *RHS) {
// TODO: we could try to find factors in all sorts of things, but for now we
// just deal with u/exact (multiply, constant). See SCEVDivision towards the
// end of this file for inspiration.

const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(LHS);
if (!Mul || !Mul->hasNoUnsignedWrap())
  return getUDivExpr(LHS, RHS);

if (const SCEVConstant *RHSCst = dyn_cast<SCEVConstant>(RHS)) {
  // If the mulexpr multiplies by a constant, then that constant must be the
  // first element of the mulexpr.
  if (const auto *LHSCst = dyn_cast<SCEVConstant>(Mul->getOperand(0))) {
    if (LHSCst == RHSCst) {
      SmallVector<const SCEV *, 2> Operands;
      Operands.append(Mul->op_begin() + 1, Mul->op_end());
      return getMulExpr(Operands);
    }

    // We can't just assume that LHSCst divides RHSCst cleanly, it could be
    // that there's a factor provided by one of the other terms. We need to
    // check.
    APInt Factor = gcd(LHSCst, RHSCst);
    if (!Factor.isIntN(1)) {
      LHSCst =
          cast<SCEVConstant>(getConstant(LHSCst->getAPInt().udiv(Factor)));
      RHSCst =
          cast<SCEVConstant>(getConstant(RHSCst->getAPInt().udiv(Factor)));
      SmallVector<const SCEV *, 2> Operands;
      Operands.push_back(LHSCst);
      Operands.append(Mul->op_begin() + 1, Mul->op_end());
      LHS = getMulExpr(Operands);
      RHS = RHSCst;
      Mul = dyn_cast<SCEVMulExpr>(LHS);
      if (!Mul)
        return getUDivExactExpr(LHS, RHS);
    }
  }
}

for (int i = 0, e = Mul->getNumOperands(); i != e; ++i) {
  if (Mul->getOperand(i) == RHS) {
    SmallVector<const SCEV *, 2> Operands;
    Operands.append(Mul->op_begin(), Mul->op_begin() + i);
    Operands.append(Mul->op_begin() + i + 1, Mul->op_end());
    return getMulExpr(Operands);
  }
}

return getUDivExpr(LHS, RHS);
3310}

3312/// Get an add recurrence expression for the specified loop.  Simplify the
3313/// expression as much as possible.
3314const SCEV *ScalarEvolution::getAddRecExpr(const SCEV *Start, const SCEV *Step,
                                         const Loop *L,
                                         SCEV::NoWrapFlags Flags) {
SmallVector<const SCEV *, 4> Operands;
Operands.push_back(Start);
if (const SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step))
  if (StepChrec->getLoop() == L) {
    Operands.append(StepChrec->op_begin(), StepChrec->op_end());
    return getAddRecExpr(Operands, L, maskFlags(Flags, SCEV::FlagNW));
  }

Operands.push_back(Step);
return getAddRecExpr(Operands, L, Flags);
3327}

3329/// Get an add recurrence expression for the specified loop.  Simplify the
3330/// expression as much as possible.
3331const SCEV *
3332ScalarEvolution::getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
                             const Loop *L, SCEV::NoWrapFlags Flags) {
if (Operands.size() == 1) return Operands[0];
3335#ifndef NDEBUG
Type *ETy = getEffectiveSCEVType(Operands[0]->getType());
for (unsigned i = 1, e = Operands.size(); i != e; ++i)
  assert(getEffectiveSCEVType(Operands[i]->getType()) == ETy &&((getEffectiveSCEVType(Operands[i]->getType()) == ETy &&
 "SCEVAddRecExpr operand types don't match!") ? static_cast<
void> (0) : __assert_fail ("getEffectiveSCEVType(Operands[i]->getType()) == ETy && \"SCEVAddRecExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3339, __PRETTY_FUNCTION__))
         "SCEVAddRecExpr operand types don't match!")((getEffectiveSCEVType(Operands[i]->getType()) == ETy &&
 "SCEVAddRecExpr operand types don't match!") ? static_cast<
void> (0) : __assert_fail ("getEffectiveSCEVType(Operands[i]->getType()) == ETy && \"SCEVAddRecExpr operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3339, __PRETTY_FUNCTION__));
for (unsigned i = 0, e = Operands.size(); i != e; ++i)
  assert(isLoopInvariant(Operands[i], L) &&((isLoopInvariant(Operands[i], L) && "SCEVAddRecExpr operand is not loop-invariant!"
) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(Operands[i], L) && \"SCEVAddRecExpr operand is not loop-invariant!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3342, __PRETTY_FUNCTION__))
         "SCEVAddRecExpr operand is not loop-invariant!")((isLoopInvariant(Operands[i], L) && "SCEVAddRecExpr operand is not loop-invariant!"
) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(Operands[i], L) && \"SCEVAddRecExpr operand is not loop-invariant!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3342, __PRETTY_FUNCTION__));
3343#endif

if (Operands.back()->isZero()) {
  Operands.pop_back();
  return getAddRecExpr(Operands, L, SCEV::FlagAnyWrap); // {X,+,0}  -->  X
}

// It's tempting to want to call getConstantMaxBackedgeTakenCount count here and
// use that information to infer NUW and NSW flags. However, computing a
// BE count requires calling getAddRecExpr, so we may not yet have a
// meaningful BE count at this point (and if we don't, we'd be stuck
// with a SCEVCouldNotCompute as the cached BE count).

Flags = StrengthenNoWrapFlags(this, scAddRecExpr, Operands, Flags);

// Canonicalize nested AddRecs in by nesting them in order of loop depth.
if (const SCEVAddRecExpr *NestedAR = dyn_cast<SCEVAddRecExpr>(Operands[0])) {
  const Loop *NestedLoop = NestedAR->getLoop();
  if (L->contains(NestedLoop)
          ? (L->getLoopDepth() < NestedLoop->getLoopDepth())
          : (!NestedLoop->contains(L) &&
             DT.dominates(L->getHeader(), NestedLoop->getHeader()))) {
    SmallVector<const SCEV *, 4> NestedOperands(NestedAR->op_begin(),
                                                NestedAR->op_end());
    Operands[0] = NestedAR->getStart();
    // AddRecs require their operands be loop-invariant with respect to their
    // loops. Don't perform this transformation if it would break this
    // requirement.
    bool AllInvariant = all_of(
        Operands, [&](const SCEV *Op) { return isLoopInvariant(Op, L); });

    if (AllInvariant) {
      // Create a recurrence for the outer loop with the same step size.
      //
      // The outer recurrence keeps its NW flag but only keeps NUW/NSW if the
      // inner recurrence has the same property.
      SCEV::NoWrapFlags OuterFlags =
        maskFlags(Flags, SCEV::FlagNW | NestedAR->getNoWrapFlags());

      NestedOperands[0] = getAddRecExpr(Operands, L, OuterFlags);
      AllInvariant = all_of(NestedOperands, [&](const SCEV *Op) {
        return isLoopInvariant(Op, NestedLoop);
      });

      if (AllInvariant) {
        // Ok, both add recurrences are valid after the transformation.
        //
        // The inner recurrence keeps its NW flag but only keeps NUW/NSW if
        // the outer recurrence has the same property.
        SCEV::NoWrapFlags InnerFlags =
          maskFlags(NestedAR->getNoWrapFlags(), SCEV::FlagNW | Flags);
        return getAddRecExpr(NestedOperands, NestedLoop, InnerFlags);
      }
    }
    // Reset Operands to its original state.
    Operands[0] = NestedAR;
  }
}

// Okay, it looks like we really DO need an addrec expr.  Check to see if we
// already have one, otherwise create a new one.
return getOrCreateAddRecExpr(Operands, L, Flags);
3405}

3407const SCEV *
3408ScalarEvolution::getGEPExpr(GEPOperator *GEP,
                          const SmallVectorImpl<const SCEV *> &IndexExprs) {
const SCEV *BaseExpr = getSCEV(GEP->getPointerOperand());
// getSCEV(Base)->getType() has the same address space as Base->getType()
// because SCEV::getType() preserves the address space.
Type *IntIdxTy = getEffectiveSCEVType(BaseExpr->getType());
// FIXME(PR23527): Don't blindly transfer the inbounds flag from the GEP
// instruction to its SCEV, because the Instruction may be guarded by control
// flow and the no-overflow bits may not be valid for the expression in any
// context. This can be fixed similarly to how these flags are handled for
// adds.
SCEV::NoWrapFlags OffsetWrap =
    GEP->isInBounds() ? SCEV::FlagNSW : SCEV::FlagAnyWrap;

Type *CurTy = GEP->getType();
bool FirstIter = true;
SmallVector<const SCEV *, 4> Offsets;
for (const SCEV *IndexExpr : IndexExprs) {
  // Compute the (potentially symbolic) offset in bytes for this index.
  if (StructType *STy = dyn_cast<StructType>(CurTy)) {
    // For a struct, add the member offset.
    ConstantInt *Index = cast<SCEVConstant>(IndexExpr)->getValue();
    unsigned FieldNo = Index->getZExtValue();
    const SCEV *FieldOffset = getOffsetOfExpr(IntIdxTy, STy, FieldNo);
    Offsets.push_back(FieldOffset);

    // Update CurTy to the type of the field at Index.
    CurTy = STy->getTypeAtIndex(Index);
  } else {
    // Update CurTy to its element type.
    if (FirstIter) {
      assert(isa<PointerType>(CurTy) &&((isa<PointerType>(CurTy) && "The first index of a GEP indexes a pointer"
) ? static_cast<void> (0) : __assert_fail ("isa<PointerType>(CurTy) && \"The first index of a GEP indexes a pointer\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3440, __PRETTY_FUNCTION__))
             "The first index of a GEP indexes a pointer")((isa<PointerType>(CurTy) && "The first index of a GEP indexes a pointer"
) ? static_cast<void> (0) : __assert_fail ("isa<PointerType>(CurTy) && \"The first index of a GEP indexes a pointer\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3440, __PRETTY_FUNCTION__));
      CurTy = GEP->getSourceElementType();
      FirstIter = false;
    } else {
      CurTy = GetElementPtrInst::getTypeAtIndex(CurTy, (uint64_t)0);
    }
    // For an array, add the element offset, explicitly scaled.
    const SCEV *ElementSize = getSizeOfExpr(IntIdxTy, CurTy);
    // Getelementptr indices are signed.
    IndexExpr = getTruncateOrSignExtend(IndexExpr, IntIdxTy);

    // Multiply the index by the element size to compute the element offset.
    const SCEV *LocalOffset = getMulExpr(IndexExpr, ElementSize, OffsetWrap);
    Offsets.push_back(LocalOffset);
  }
}

// Handle degenerate case of GEP without offsets.
if (Offsets.empty())
  return BaseExpr;

// Add the offsets together, assuming nsw if inbounds.
const SCEV *Offset = getAddExpr(Offsets, OffsetWrap);
// Add the base address and the offset. We cannot use the nsw flag, as the
// base address is unsigned. However, if we know that the offset is
// non-negative, we can use nuw.
SCEV::NoWrapFlags BaseWrap = GEP->isInBounds() && isKnownNonNegative(Offset)
                                 ? SCEV::FlagNUW : SCEV::FlagAnyWrap;
return getAddExpr(BaseExpr, Offset, BaseWrap);
3469}

3471std::tuple<SCEV *, FoldingSetNodeID, void *>
3472ScalarEvolution::findExistingSCEVInCache(SCEVTypes SCEVType,
                                       ArrayRef<const SCEV *> Ops) {
FoldingSetNodeID ID;
void *IP = nullptr;
ID.AddInteger(SCEVType);
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
  ID.AddPointer(Ops[i]);
return std::tuple<SCEV *, FoldingSetNodeID, void *>(
    UniqueSCEVs.FindNodeOrInsertPos(ID, IP), std::move(ID), IP);
3481}

3483const SCEV *ScalarEvolution::getAbsExpr(const SCEV *Op, bool IsNSW) {
SCEV::NoWrapFlags Flags = IsNSW ? SCEV::FlagNSW : SCEV::FlagAnyWrap;
return getSMaxExpr(Op, getNegativeSCEV(Op, Flags));
3486}

3488const SCEV *ScalarEvolution::getSignumExpr(const SCEV *Op) {
Type *Ty = Op->getType();
return getSMinExpr(getSMaxExpr(Op, getMinusOne(Ty)), getOne(Ty));
3491}

3493const SCEV *ScalarEvolution::getMinMaxExpr(SCEVTypes Kind,
                                         SmallVectorImpl<const SCEV *> &Ops) {
assert(!Ops.empty() && "Cannot get empty (u|s)(min|max)!")((!Ops.empty() && "Cannot get empty (u|s)(min|max)!")
 ? static_cast<void> (0) : __assert_fail ("!Ops.empty() && \"Cannot get empty (u|s)(min|max)!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3495, __PRETTY_FUNCTION__));
if (Ops.size() == 1) return Ops[0];
3497#ifndef NDEBUG
Type *ETy = getEffectiveSCEVType(Ops[0]->getType());
for (unsigned i = 1, e = Ops.size(); i != e; ++i)
  assert(getEffectiveSCEVType(Ops[i]->getType()) == ETy &&((getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
 "Operand types don't match!") ? static_cast<void> (0) :
 __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"Operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3501, __PRETTY_FUNCTION__))
         "Operand types don't match!")((getEffectiveSCEVType(Ops[i]->getType()) == ETy &&
 "Operand types don't match!") ? static_cast<void> (0) :
 __assert_fail ("getEffectiveSCEVType(Ops[i]->getType()) == ETy && \"Operand types don't match!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3501, __PRETTY_FUNCTION__));
3502#endif

bool IsSigned = Kind == scSMaxExpr || Kind == scSMinExpr;
bool IsMax = Kind == scSMaxExpr || Kind == scUMaxExpr;

// Sort by complexity, this groups all similar expression types together.
GroupByComplexity(Ops, &LI, DT);

// Check if we have created the same expression before.
if (const SCEV *S = std::get<0>(findExistingSCEVInCache(Kind, Ops))) {
  return S;
}

// If there are any constants, fold them together.
unsigned Idx = 0;
if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(Ops[0])) {
  ++Idx;
  assert(Idx < Ops.size())((Idx < Ops.size()) ? static_cast<void> (0) : __assert_fail
 ("Idx < Ops.size()", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3519, __PRETTY_FUNCTION__));
  auto FoldOp = [&](const APInt &LHS, const APInt &RHS) {
    if (Kind == scSMaxExpr)
      return APIntOps::smax(LHS, RHS);
    else if (Kind == scSMinExpr)
      return APIntOps::smin(LHS, RHS);
    else if (Kind == scUMaxExpr)
      return APIntOps::umax(LHS, RHS);
    else if (Kind == scUMinExpr)
      return APIntOps::umin(LHS, RHS);
    llvm_unreachable("Unknown SCEV min/max opcode")::llvm::llvm_unreachable_internal("Unknown SCEV min/max opcode"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3529);
  };

  while (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(Ops[Idx])) {
    // We found two constants, fold them together!
    ConstantInt *Fold = ConstantInt::get(
        getContext(), FoldOp(LHSC->getAPInt(), RHSC->getAPInt()));
    Ops[0] = getConstant(Fold);
    Ops.erase(Ops.begin()+1);  // Erase the folded element
    if (Ops.size() == 1) return Ops[0];
    LHSC = cast<SCEVConstant>(Ops[0]);
  }

  bool IsMinV = LHSC->getValue()->isMinValue(IsSigned);
  bool IsMaxV = LHSC->getValue()->isMaxValue(IsSigned);

  if (IsMax ? IsMinV : IsMaxV) {
    // If we are left with a constant minimum(/maximum)-int, strip it off.
    Ops.erase(Ops.begin());
    --Idx;
  } else if (IsMax ? IsMaxV : IsMinV) {
    // If we have a max(/min) with a constant maximum(/minimum)-int,
    // it will always be the extremum.
    return LHSC;
  }

  if (Ops.size() == 1) return Ops[0];
}

// Find the first operation of the same kind
while (Idx < Ops.size() && Ops[Idx]->getSCEVType() < Kind)
  ++Idx;

// Check to see if one of the operands is of the same kind. If so, expand its
// operands onto our operand list, and recurse to simplify.
if (Idx < Ops.size()) {
  bool DeletedAny = false;
  while (Ops[Idx]->getSCEVType() == Kind) {
    const SCEVMinMaxExpr *SMME = cast<SCEVMinMaxExpr>(Ops[Idx]);
    Ops.erase(Ops.begin()+Idx);
    Ops.append(SMME->op_begin(), SMME->op_end());
    DeletedAny = true;
  }

  if (DeletedAny)
    return getMinMaxExpr(Kind, Ops);
}

// Okay, check to see if the same value occurs in the operand list twice.  If
// so, delete one.  Since we sorted the list, these values are required to
// be adjacent.
llvm::CmpInst::Predicate GEPred =
    IsSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
llvm::CmpInst::Predicate LEPred =
    IsSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
llvm::CmpInst::Predicate FirstPred = IsMax ? GEPred : LEPred;
llvm::CmpInst::Predicate SecondPred = IsMax ? LEPred : GEPred;
for (unsigned i = 0, e = Ops.size() - 1; i != e; ++i) {
  if (Ops[i] == Ops[i + 1] ||
      isKnownViaNonRecursiveReasoning(FirstPred, Ops[i], Ops[i + 1])) {
    //  X op Y op Y  -->  X op Y
    //  X op Y       -->  X, if we know X, Y are ordered appropriately
    Ops.erase(Ops.begin() + i + 1, Ops.begin() + i + 2);
    --i;
    --e;
  } else if (isKnownViaNonRecursiveReasoning(SecondPred, Ops[i],
                                             Ops[i + 1])) {
    //  X op Y       -->  Y, if we know X, Y are ordered appropriately
    Ops.erase(Ops.begin() + i, Ops.begin() + i + 1);
    --i;
    --e;
  }
}

if (Ops.size() == 1) return Ops[0];

assert(!Ops.empty() && "Reduced smax down to nothing!")((!Ops.empty() && "Reduced smax down to nothing!") ? static_cast
<void> (0) : __assert_fail ("!Ops.empty() && \"Reduced smax down to nothing!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3605, __PRETTY_FUNCTION__));

// Okay, it looks like we really DO need an expr.  Check to see if we
// already have one, otherwise create a new one.
const SCEV *ExistingSCEV;
FoldingSetNodeID ID;
void *IP;
std::tie(ExistingSCEV, ID, IP) = findExistingSCEVInCache(Kind, Ops);
if (ExistingSCEV)
  return ExistingSCEV;
const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
std::uninitialized_copy(Ops.begin(), Ops.end(), O);
SCEV *S = new (SCEVAllocator)
    SCEVMinMaxExpr(ID.Intern(SCEVAllocator), Kind, O, Ops.size());

UniqueSCEVs.InsertNode(S, IP);
addToLoopUseLists(S);
return S;
3623}

3625const SCEV *ScalarEvolution::getSMaxExpr(const SCEV *LHS, const SCEV *RHS) {
SmallVector<const SCEV *, 2> Ops = {LHS, RHS};
return getSMaxExpr(Ops);
3628}

3630const SCEV *ScalarEvolution::getSMaxExpr(SmallVectorImpl<const SCEV *> &Ops) {
return getMinMaxExpr(scSMaxExpr, Ops);
3632}

3634const SCEV *ScalarEvolution::getUMaxExpr(const SCEV *LHS, const SCEV *RHS) {
SmallVector<const SCEV *, 2> Ops = {LHS, RHS};
return getUMaxExpr(Ops);
3637}

3639const SCEV *ScalarEvolution::getUMaxExpr(SmallVectorImpl<const SCEV *> &Ops) {
return getMinMaxExpr(scUMaxExpr, Ops);
3641}

3643const SCEV *ScalarEvolution::getSMinExpr(const SCEV *LHS,
                                       const SCEV *RHS) {
SmallVector<const SCEV *, 2> Ops = { LHS, RHS };
return getSMinExpr(Ops);
3647}

3649const SCEV *ScalarEvolution::getSMinExpr(SmallVectorImpl<const SCEV *> &Ops) {
return getMinMaxExpr(scSMinExpr, Ops);
3651}

3653const SCEV *ScalarEvolution::getUMinExpr(const SCEV *LHS,
                                       const SCEV *RHS) {
SmallVector<const SCEV *, 2> Ops = { LHS, RHS };
return getUMinExpr(Ops);
3657}

3659const SCEV *ScalarEvolution::getUMinExpr(SmallVectorImpl<const SCEV *> &Ops) {
return getMinMaxExpr(scUMinExpr, Ops);
3661}

3663const SCEV *ScalarEvolution::getSizeOfExpr(Type *IntTy, Type *AllocTy) {
if (isa<ScalableVectorType>(AllocTy)) {
  Constant *NullPtr = Constant::getNullValue(AllocTy->getPointerTo());
  Constant *One = ConstantInt::get(IntTy, 1);
  Constant *GEP = ConstantExpr::getGetElementPtr(AllocTy, NullPtr, One);
  // Note that the expression we created is the final expression, we don't
  // want to simplify it any further Also, if we call a normal getSCEV(),
  // we'll end up in an endless recursion. So just create an SCEVUnknown.
  return getUnknown(ConstantExpr::getPtrToInt(GEP, IntTy));
}
// We can bypass creating a target-independent
// constant expression and then folding it back into a ConstantInt.
// This is just a compile-time optimization.
return getConstant(IntTy, getDataLayout().getTypeAllocSize(AllocTy));
3677}

3679const SCEV *ScalarEvolution::getOffsetOfExpr(Type *IntTy,
                                           StructType *STy,
                                           unsigned FieldNo) {
// We can bypass creating a target-independent
// constant expression and then folding it back into a ConstantInt.
// This is just a compile-time optimization.
return getConstant(
    IntTy, getDataLayout().getStructLayout(STy)->getElementOffset(FieldNo));
3687}

3689const SCEV *ScalarEvolution::getUnknown(Value *V) {
// Don't attempt to do anything other than create a SCEVUnknown object
// here.  createSCEV only calls getUnknown after checking for all other
// interesting possibilities, and any other code that calls getUnknown
// is doing so in order to hide a value from SCEV canonicalization.

FoldingSetNodeID ID;
ID.AddInteger(scUnknown);
ID.AddPointer(V);
void *IP = nullptr;
if (SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) {
  assert(cast<SCEVUnknown>(S)->getValue() == V &&((cast<SCEVUnknown>(S)->getValue() == V && "Stale SCEVUnknown in uniquing map!"
) ? static_cast<void> (0) : __assert_fail ("cast<SCEVUnknown>(S)->getValue() == V && \"Stale SCEVUnknown in uniquing map!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3701, __PRETTY_FUNCTION__))
         "Stale SCEVUnknown in uniquing map!")((cast<SCEVUnknown>(S)->getValue() == V && "Stale SCEVUnknown in uniquing map!"
) ? static_cast<void> (0) : __assert_fail ("cast<SCEVUnknown>(S)->getValue() == V && \"Stale SCEVUnknown in uniquing map!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3701, __PRETTY_FUNCTION__));
  return S;
}
SCEV *S = new (SCEVAllocator) SCEVUnknown(ID.Intern(SCEVAllocator), V, this,
                                          FirstUnknown);
FirstUnknown = cast<SCEVUnknown>(S);
UniqueSCEVs.InsertNode(S, IP);
return S;
3709}

3711//===----------------------------------------------------------------------===//
3712//            Basic SCEV Analysis and PHI Idiom Recognition Code
3713//

3715/// Test if values of the given type are analyzable within the SCEV
3716/// framework. This primarily includes integer types, and it can optionally
3717/// include pointer types if the ScalarEvolution class has access to
3718/// target-specific information.
3719bool ScalarEvolution::isSCEVable(Type *Ty) const {
// Integers and pointers are always SCEVable.
return Ty->isIntOrPtrTy();
3722}

3724/// Return the size in bits of the specified type, for which isSCEVable must
3725/// return true.
3726uint64_t ScalarEvolution::getTypeSizeInBits(Type *Ty) const {
assert(isSCEVable(Ty) && "Type is not SCEVable!")((isSCEVable(Ty) && "Type is not SCEVable!") ? static_cast
<void> (0) : __assert_fail ("isSCEVable(Ty) && \"Type is not SCEVable!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3727, __PRETTY_FUNCTION__));
if (Ty->isPointerTy())
  return getDataLayout().getIndexTypeSizeInBits(Ty);
return getDataLayout().getTypeSizeInBits(Ty);
3731}

3733/// Return a type with the same bitwidth as the given type and which represents
3734/// how SCEV will treat the given type, for which isSCEVable must return
3735/// true. For pointer types, this is the pointer index sized integer type.
3736Type *ScalarEvolution::getEffectiveSCEVType(Type *Ty) const {
assert(isSCEVable(Ty) && "Type is not SCEVable!")((isSCEVable(Ty) && "Type is not SCEVable!") ? static_cast
<void> (0) : __assert_fail ("isSCEVable(Ty) && \"Type is not SCEVable!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3737, __PRETTY_FUNCTION__));

if (Ty->isIntegerTy())
  return Ty;

// The only other support type is pointer.
assert(Ty->isPointerTy() && "Unexpected non-pointer non-integer type!")((Ty->isPointerTy() && "Unexpected non-pointer non-integer type!"
) ? static_cast<void> (0) : __assert_fail ("Ty->isPointerTy() && \"Unexpected non-pointer non-integer type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3743, __PRETTY_FUNCTION__));
return getDataLayout().getIndexType(Ty);
3745}

3747Type *ScalarEvolution::getWiderType(Type *T1, Type *T2) const {
return  getTypeSizeInBits(T1) >= getTypeSizeInBits(T2) ? T1 : T2;
3749}

3751const SCEV *ScalarEvolution::getCouldNotCompute() {
return CouldNotCompute.get();
3753}

3755bool ScalarEvolution::checkValidity(const SCEV *S) const {
bool ContainsNulls = SCEVExprContains(S, [](const SCEV *S) {
  auto *SU = dyn_cast<SCEVUnknown>(S);
  return SU && SU->getValue() == nullptr;
});

return !ContainsNulls;
3762}

3764bool ScalarEvolution::containsAddRecurrence(const SCEV *S) {
HasRecMapType::iterator I = HasRecMap.find(S);
if (I != HasRecMap.end())
  return I->second;

bool FoundAddRec =
    SCEVExprContains(S, [](const SCEV *S) { return isa<SCEVAddRecExpr>(S); });
HasRecMap.insert({S, FoundAddRec});
return FoundAddRec;
3773}

3775/// Try to split a SCEVAddExpr into a pair of {SCEV, ConstantInt}.
3776/// If \p S is a SCEVAddExpr and is composed of a sub SCEV S' and an
3777/// offset I, then return {S', I}, else return {\p S, nullptr}.
3778static std::pair<const SCEV *, ConstantInt *> splitAddExpr(const SCEV *S) {
const auto *Add = dyn_cast<SCEVAddExpr>(S);
if (!Add)
  return {S, nullptr};

if (Add->getNumOperands() != 2)
  return {S, nullptr};

auto *ConstOp = dyn_cast<SCEVConstant>(Add->getOperand(0));
if (!ConstOp)
  return {S, nullptr};

return {Add->getOperand(1), ConstOp->getValue()};
3791}

3793/// Return the ValueOffsetPair set for \p S. \p S can be represented
3794/// by the value and offset from any ValueOffsetPair in the set.
3795SetVector<ScalarEvolution::ValueOffsetPair> *
3796ScalarEvolution::getSCEVValues(const SCEV *S) {
ExprValueMapType::iterator SI = ExprValueMap.find_as(S);
if (SI == ExprValueMap.end())
  return nullptr;
3800#ifndef NDEBUG
if (VerifySCEVMap) {
  // Check there is no dangling Value in the set returned.
  for (const auto &VE : SI->second)
    assert(ValueExprMap.count(VE.first))((ValueExprMap.count(VE.first)) ? static_cast<void> (0)
 : __assert_fail ("ValueExprMap.count(VE.first)", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3804, __PRETTY_FUNCTION__));
}
3806#endif
return &SI->second;
3808}

3810/// Erase Value from ValueExprMap and ExprValueMap. ValueExprMap.erase(V)
3811/// cannot be used separately. eraseValueFromMap should be used to remove
3812/// V from ValueExprMap and ExprValueMap at the same time.
3813void ScalarEvolution::eraseValueFromMap(Value *V) {
ValueExprMapType::iterator I = ValueExprMap.find_as(V);
if (I != ValueExprMap.end()) {
  const SCEV *S = I->second;
  // Remove {V, 0} from the set of ExprValueMap[S]
  if (SetVector<ValueOffsetPair> *SV = getSCEVValues(S))
    SV->remove({V, nullptr});

  // Remove {V, Offset} from the set of ExprValueMap[Stripped]
  const SCEV *Stripped;
  ConstantInt *Offset;
  std::tie(Stripped, Offset) = splitAddExpr(S);
  if (Offset != nullptr) {
    if (SetVector<ValueOffsetPair> *SV = getSCEVValues(Stripped))
      SV->remove({V, Offset});
  }
  ValueExprMap.erase(V);
}
3831}

3833/// Check whether value has nuw/nsw/exact set but SCEV does not.
3834/// TODO: In reality it is better to check the poison recursively
3835/// but this is better than nothing.
3836static bool SCEVLostPoisonFlags(const SCEV *S, const Value *V) {
if (auto *I = dyn_cast<Instruction>(V)) {
  if (isa<OverflowingBinaryOperator>(I)) {
    if (auto *NS = dyn_cast<SCEVNAryExpr>(S)) {
      if (I->hasNoSignedWrap() && !NS->hasNoSignedWrap())
        return true;
      if (I->hasNoUnsignedWrap() && !NS->hasNoUnsignedWrap())
        return true;
    }
  } else if (isa<PossiblyExactOperator>(I) && I->isExact())
    return true;
}
return false;
3849}

3851/// Return an existing SCEV if it exists, otherwise analyze the expression and
3852/// create a new one.
3853const SCEV *ScalarEvolution::getSCEV(Value *V) {
assert(isSCEVable(V->getType()) && "Value is not SCEVable!")((isSCEVable(V->getType()) && "Value is not SCEVable!"
) ? static_cast<void> (0) : __assert_fail ("isSCEVable(V->getType()) && \"Value is not SCEVable!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3854, __PRETTY_FUNCTION__));

const SCEV *S = getExistingSCEV(V);
if (S == nullptr) {
  S = createSCEV(V);
  // During PHI resolution, it is possible to create two SCEVs for the same
  // V, so it is needed to double check whether V->S is inserted into
  // ValueExprMap before insert S->{V, 0} into ExprValueMap.
  std::pair<ValueExprMapType::iterator, bool> Pair =
      ValueExprMap.insert({SCEVCallbackVH(V, this), S});
  if (Pair.second && !SCEVLostPoisonFlags(S, V)) {
    ExprValueMap[S].insert({V, nullptr});

    // If S == Stripped + Offset, add Stripped -> {V, Offset} into
    // ExprValueMap.
    const SCEV *Stripped = S;
    ConstantInt *Offset = nullptr;
    std::tie(Stripped, Offset) = splitAddExpr(S);
    // If stripped is SCEVUnknown, don't bother to save
    // Stripped -> {V, offset}. It doesn't simplify and sometimes even
    // increase the complexity of the expansion code.
    // If V is GetElementPtrInst, don't save Stripped -> {V, offset}
    // because it may generate add/sub instead of GEP in SCEV expansion.
    if (Offset != nullptr && !isa<SCEVUnknown>(Stripped) &&
        !isa<GetElementPtrInst>(V))
      ExprValueMap[Stripped].insert({V, Offset});
  }
}
return S;
3883}

3885const SCEV *ScalarEvolution::getExistingSCEV(Value *V) {
assert(isSCEVable(V->getType()) && "Value is not SCEVable!")((isSCEVable(V->getType()) && "Value is not SCEVable!"
) ? static_cast<void> (0) : __assert_fail ("isSCEVable(V->getType()) && \"Value is not SCEVable!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3886, __PRETTY_FUNCTION__));

ValueExprMapType::iterator I = ValueExprMap.find_as(V);
if (I != ValueExprMap.end()) {
  const SCEV *S = I->second;
  if (checkValidity(S))
    return S;
  eraseValueFromMap(V);
  forgetMemoizedResults(S);
}
return nullptr;
3897}

3899/// Return a SCEV corresponding to -V = -1*V
3900const SCEV *ScalarEvolution::getNegativeSCEV(const SCEV *V,
                                           SCEV::NoWrapFlags Flags) {
if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
  return getConstant(
             cast<ConstantInt>(ConstantExpr::getNeg(VC->getValue())));

Type *Ty = V->getType();
Ty = getEffectiveSCEVType(Ty);
return getMulExpr(V, getMinusOne(Ty), Flags);
3909}

3911/// If Expr computes ~A, return A else return nullptr
3912static const SCEV *MatchNotExpr(const SCEV *Expr) {
const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Expr);
if (!Add || Add->getNumOperands() != 2 ||
    !Add->getOperand(0)->isAllOnesValue())
  return nullptr;

const SCEVMulExpr *AddRHS = dyn_cast<SCEVMulExpr>(Add->getOperand(1));
if (!AddRHS || AddRHS->getNumOperands() != 2 ||
    !AddRHS->getOperand(0)->isAllOnesValue())
  return nullptr;

return AddRHS->getOperand(1);
3924}

3926/// Return a SCEV corresponding to ~V = -1-V
3927const SCEV *ScalarEvolution::getNotSCEV(const SCEV *V) {
if (const SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
  return getConstant(
              cast<ConstantInt>(ConstantExpr::getNot(VC->getValue())));

// Fold ~(u|s)(min|max)(~x, ~y) to (u|s)(max|min)(x, y)
if (const SCEVMinMaxExpr *MME = dyn_cast<SCEVMinMaxExpr>(V)) {
  auto MatchMinMaxNegation = [&](const SCEVMinMaxExpr *MME) {
    SmallVector<const SCEV *, 2> MatchedOperands;
    for (const SCEV *Operand : MME->operands()) {
      const SCEV *Matched = MatchNotExpr(Operand);
      if (!Matched)
        return (const SCEV *)nullptr;
      MatchedOperands.push_back(Matched);
    }
    return getMinMaxExpr(SCEVMinMaxExpr::negate(MME->getSCEVType()),
                         MatchedOperands);
  };
  if (const SCEV *Replaced = MatchMinMaxNegation(MME))
    return Replaced;
}

Type *Ty = V->getType();
Ty = getEffectiveSCEVType(Ty);
return getMinusSCEV(getMinusOne(Ty), V);
3952}

3954const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS, const SCEV *RHS,
                                        SCEV::NoWrapFlags Flags,
                                        unsigned Depth) {
// Fast path: X - X --> 0.
if (LHS == RHS)
  return getZero(LHS->getType());

// We represent LHS - RHS as LHS + (-1)*RHS. This transformation
// makes it so that we cannot make much use of NUW.
auto AddFlags = SCEV::FlagAnyWrap;
const bool RHSIsNotMinSigned =
    !getSignedRangeMin(RHS).isMinSignedValue();
if (maskFlags(Flags, SCEV::FlagNSW) == SCEV::FlagNSW) {
  // Let M be the minimum representable signed value. Then (-1)*RHS
  // signed-wraps if and only if RHS is M. That can happen even for
  // a NSW subtraction because e.g. (-1)*M signed-wraps even though
  // -1 - M does not. So to transfer NSW from LHS - RHS to LHS +
  // (-1)*RHS, we need to prove that RHS != M.
  //
  // If LHS is non-negative and we know that LHS - RHS does not
  // signed-wrap, then RHS cannot be M. So we can rule out signed-wrap
  // either by proving that RHS > M or that LHS >= 0.
  if (RHSIsNotMinSigned || isKnownNonNegative(LHS)) {
    AddFlags = SCEV::FlagNSW;
  }
}

// FIXME: Find a correct way to transfer NSW to (-1)*M when LHS -
// RHS is NSW and LHS >= 0.
//
// The difficulty here is that the NSW flag may have been proven
// relative to a loop that is to be found in a recurrence in LHS and
// not in RHS. Applying NSW to (-1)*M may then let the NSW have a
// larger scope than intended.
auto NegFlags = RHSIsNotMinSigned ? SCEV::FlagNSW : SCEV::FlagAnyWrap;

return getAddExpr(LHS, getNegativeSCEV(RHS, NegFlags), AddFlags, Depth);
3991}

3993const SCEV *ScalarEvolution::getTruncateOrZeroExtend(const SCEV *V, Type *Ty,
                                                   unsigned Depth) {
Type *SrcTy = V->getType();
assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot truncate or zero extend with non-integer arguments!"
) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3997, __PRETTY_FUNCTION__))
       "Cannot truncate or zero extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot truncate or zero extend with non-integer arguments!"
) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 3997, __PRETTY_FUNCTION__));
if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
  return V;  // No conversion
if (getTypeSizeInBits(SrcTy) > getTypeSizeInBits(Ty))
  return getTruncateExpr(V, Ty, Depth);
return getZeroExtendExpr(V, Ty, Depth);
4003}

4005const SCEV *ScalarEvolution::getTruncateOrSignExtend(const SCEV *V, Type *Ty,
                                                   unsigned Depth) {
Type *SrcTy = V->getType();
assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot truncate or zero extend with non-integer arguments!"
) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4009, __PRETTY_FUNCTION__))
       "Cannot truncate or zero extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot truncate or zero extend with non-integer arguments!"
) ? static_cast<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or zero extend with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4009, __PRETTY_FUNCTION__));
if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
  return V;  // No conversion
if (getTypeSizeInBits(SrcTy) > getTypeSizeInBits(Ty))
  return getTruncateExpr(V, Ty, Depth);
return getSignExtendExpr(V, Ty, Depth);
4015}

4017const SCEV *
4018ScalarEvolution::getNoopOrZeroExtend(const SCEV *V, Type *Ty) {
Type *SrcTy = V->getType();
assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot noop or zero extend with non-integer arguments!") ? static_cast
<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or zero extend with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4021, __PRETTY_FUNCTION__))
       "Cannot noop or zero extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot noop or zero extend with non-integer arguments!") ? static_cast
<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or zero extend with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4021, __PRETTY_FUNCTION__));
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
 "getNoopOrZeroExtend cannot truncate!") ? static_cast<void
> (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrZeroExtend cannot truncate!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4023, __PRETTY_FUNCTION__))
       "getNoopOrZeroExtend cannot truncate!")((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
 "getNoopOrZeroExtend cannot truncate!") ? static_cast<void
> (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrZeroExtend cannot truncate!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4023, __PRETTY_FUNCTION__));
if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
  return V;  // No conversion
return getZeroExtendExpr(V, Ty);
4027}

4029const SCEV *
4030ScalarEvolution::getNoopOrSignExtend(const SCEV *V, Type *Ty) {
Type *SrcTy = V->getType();
assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot noop or sign extend with non-integer arguments!") ? static_cast
<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or sign extend with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4033, __PRETTY_FUNCTION__))
       "Cannot noop or sign extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot noop or sign extend with non-integer arguments!") ? static_cast
<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or sign extend with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4033, __PRETTY_FUNCTION__));
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
 "getNoopOrSignExtend cannot truncate!") ? static_cast<void
> (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrSignExtend cannot truncate!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4035, __PRETTY_FUNCTION__))
       "getNoopOrSignExtend cannot truncate!")((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
 "getNoopOrSignExtend cannot truncate!") ? static_cast<void
> (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrSignExtend cannot truncate!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4035, __PRETTY_FUNCTION__));
if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
  return V;  // No conversion
return getSignExtendExpr(V, Ty);
4039}

4041const SCEV *
4042ScalarEvolution::getNoopOrAnyExtend(const SCEV *V, Type *Ty) {
Type *SrcTy = V->getType();
assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot noop or any extend with non-integer arguments!") ? static_cast
<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or any extend with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4045, __PRETTY_FUNCTION__))
       "Cannot noop or any extend with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot noop or any extend with non-integer arguments!") ? static_cast
<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot noop or any extend with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4045, __PRETTY_FUNCTION__));
assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
 "getNoopOrAnyExtend cannot truncate!") ? static_cast<void
> (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrAnyExtend cannot truncate!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4047, __PRETTY_FUNCTION__))
       "getNoopOrAnyExtend cannot truncate!")((getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
 "getNoopOrAnyExtend cannot truncate!") ? static_cast<void
> (0) : __assert_fail ("getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) && \"getNoopOrAnyExtend cannot truncate!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4047, __PRETTY_FUNCTION__));
if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
  return V;  // No conversion
return getAnyExtendExpr(V, Ty);
4051}

4053const SCEV *
4054ScalarEvolution::getTruncateOrNoop(const SCEV *V, Type *Ty) {
Type *SrcTy = V->getType();
assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot truncate or noop with non-integer arguments!") ? static_cast
<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or noop with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4057, __PRETTY_FUNCTION__))
       "Cannot truncate or noop with non-integer arguments!")((SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
 "Cannot truncate or noop with non-integer arguments!") ? static_cast
<void> (0) : __assert_fail ("SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() && \"Cannot truncate or noop with non-integer arguments!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4057, __PRETTY_FUNCTION__));
assert(getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) &&((getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) &&
 "getTruncateOrNoop cannot extend!") ? static_cast<void>
 (0) : __assert_fail ("getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) && \"getTruncateOrNoop cannot extend!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4059, __PRETTY_FUNCTION__))
       "getTruncateOrNoop cannot extend!")((getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) &&
 "getTruncateOrNoop cannot extend!") ? static_cast<void>
 (0) : __assert_fail ("getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) && \"getTruncateOrNoop cannot extend!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4059, __PRETTY_FUNCTION__));
if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
  return V;  // No conversion
return getTruncateExpr(V, Ty);
4063}

4065const SCEV *ScalarEvolution::getUMaxFromMismatchedTypes(const SCEV *LHS,
                                                      const SCEV *RHS) {
const SCEV *PromotedLHS = LHS;
const SCEV *PromotedRHS = RHS;

if (getTypeSizeInBits(LHS->getType()) > getTypeSizeInBits(RHS->getType()))
  PromotedRHS = getZeroExtendExpr(RHS, LHS->getType());
else
  PromotedLHS = getNoopOrZeroExtend(LHS, RHS->getType());

return getUMaxExpr(PromotedLHS, PromotedRHS);
4076}

4078const SCEV *ScalarEvolution::getUMinFromMismatchedTypes(const SCEV *LHS,
                                                      const SCEV *RHS) {
SmallVector<const SCEV *, 2> Ops = { LHS, RHS };
return getUMinFromMismatchedTypes(Ops);
4082}

4084const SCEV *ScalarEvolution::getUMinFromMismatchedTypes(
  SmallVectorImpl<const SCEV *> &Ops) {
assert(!Ops.empty() && "At least one operand must be!")((!Ops.empty() && "At least one operand must be!") ? static_cast
<void> (0) : __assert_fail ("!Ops.empty() && \"At least one operand must be!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4086, __PRETTY_FUNCTION__));
// Trivial case.
if (Ops.size() == 1)
  return Ops[0];

// Find the max type first.
Type *MaxType = nullptr;
for (auto *S : Ops)
  if (MaxType)
    MaxType = getWiderType(MaxType, S->getType());
  else
    MaxType = S->getType();
assert(MaxType && "Failed to find maximum type!")((MaxType && "Failed to find maximum type!") ? static_cast
<void> (0) : __assert_fail ("MaxType && \"Failed to find maximum type!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4098, __PRETTY_FUNCTION__));

// Extend all ops to max type.
SmallVector<const SCEV *, 2> PromotedOps;
for (auto *S : Ops)
  PromotedOps.push_back(getNoopOrZeroExtend(S, MaxType));

// Generate umin.
return getUMinExpr(PromotedOps);
4107}

4109const SCEV *ScalarEvolution::getPointerBase(const SCEV *V) {
// A pointer operand may evaluate to a nonpointer expression, such as null.
if (!V->getType()->isPointerTy())
  return V;

while (true) {
  if (const SCEVIntegralCastExpr *Cast = dyn_cast<SCEVIntegralCastExpr>(V)) {
    V = Cast->getOperand();
  } else if (const SCEVNAryExpr *NAry = dyn_cast<SCEVNAryExpr>(V)) {
    const SCEV *PtrOp = nullptr;
    for (const SCEV *NAryOp : NAry->operands()) {
      if (NAryOp->getType()->isPointerTy()) {
        // Cannot find the base of an expression with multiple pointer ops.
        if (PtrOp)
          return V;
        PtrOp = NAryOp;
      }
    }
    if (!PtrOp) // All operands were non-pointer.
      return V;
    V = PtrOp;
  } else // Not something we can look further into.
    return V;
}
4133}

4135/// Push users of the given Instruction onto the given Worklist.
4136static void
4137PushDefUseChildren(Instruction *I,
                 SmallVectorImpl<Instruction *> &Worklist) {
// Push the def-use children onto the Worklist stack.
for (User *U : I->users())
  Worklist.push_back(cast<Instruction>(U));
4142}

4144void ScalarEvolution::forgetSymbolicName(Instruction *PN, const SCEV *SymName) {
SmallVector<Instruction *, 16> Worklist;
PushDefUseChildren(PN, Worklist);

SmallPtrSet<Instruction *, 8> Visited;
Visited.insert(PN);
while (!Worklist.empty()) {
  Instruction *I = Worklist.pop_back_val();
  if (!Visited.insert(I).second)
    continue;

  auto It = ValueExprMap.find_as(static_cast<Value *>(I));
  if (It != ValueExprMap.end()) {
    const SCEV *Old = It->second;

    // Short-circuit the def-use traversal if the symbolic name
    // ceases to appear in expressions.
    if (Old != SymName && !hasOperand(Old, SymName))
      continue;

    // SCEVUnknown for a PHI either means that it has an unrecognized
    // structure, it's a PHI that's in the progress of being computed
    // by createNodeForPHI, or it's a single-value PHI. In the first case,
    // additional loop trip count information isn't going to change anything.
    // In the second case, createNodeForPHI will perform the necessary
    // updates on its own when it gets to that point. In the third, we do
    // want to forget the SCEVUnknown.
    if (!isa<PHINode>(I) ||
        !isa<SCEVUnknown>(Old) ||
        (I != PN && Old == SymName)) {
      eraseValueFromMap(It->first);
      forgetMemoizedResults(Old);
    }
  }

  PushDefUseChildren(I, Worklist);
}
4181}

4183namespace {

4185/// Takes SCEV S and Loop L. For each AddRec sub-expression, use its start
4186/// expression in case its Loop is L. If it is not L then
4187/// if IgnoreOtherLoops is true then use AddRec itself
4188/// otherwise rewrite cannot be done.
4189/// If SCEV contains non-invariant unknown SCEV rewrite cannot be done.
4190class SCEVInitRewriter : public SCEVRewriteVisitor<SCEVInitRewriter> {
4191public:
static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE,
                           bool IgnoreOtherLoops = true) {
  SCEVInitRewriter Rewriter(L, SE);
  const SCEV *Result = Rewriter.visit(S);
  if (Rewriter.hasSeenLoopVariantSCEVUnknown())
    return SE.getCouldNotCompute();
  return Rewriter.hasSeenOtherLoops() && !IgnoreOtherLoops
             ? SE.getCouldNotCompute()
             : Result;
}

const SCEV *visitUnknown(const SCEVUnknown *Expr) {
  if (!SE.isLoopInvariant(Expr, L))
    SeenLoopVariantSCEVUnknown = true;
  return Expr;
}

const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
  // Only re-write AddRecExprs for this loop.
  if (Expr->getLoop() == L)
    return Expr->getStart();
  SeenOtherLoops = true;
  return Expr;
}

bool hasSeenLoopVariantSCEVUnknown() { return SeenLoopVariantSCEVUnknown; }

bool hasSeenOtherLoops() { return SeenOtherLoops; }

4221private:
explicit SCEVInitRewriter(const Loop *L, ScalarEvolution &SE)
    : SCEVRewriteVisitor(SE), L(L) {}

const Loop *L;
bool SeenLoopVariantSCEVUnknown = false;
bool SeenOtherLoops = false;
4228};

4230/// Takes SCEV S and Loop L. For each AddRec sub-expression, use its post
4231/// increment expression in case its Loop is L. If it is not L then
4232/// use AddRec itself.
4233/// If SCEV contains non-invariant unknown SCEV rewrite cannot be done.
4234class SCEVPostIncRewriter : public SCEVRewriteVisitor<SCEVPostIncRewriter> {
4235public:
static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE) {
  SCEVPostIncRewriter Rewriter(L, SE);
  const SCEV *Result = Rewriter.visit(S);
  return Rewriter.hasSeenLoopVariantSCEVUnknown()
      ? SE.getCouldNotCompute()
      : Result;
}

const SCEV *visitUnknown(const SCEVUnknown *Expr) {
  if (!SE.isLoopInvariant(Expr, L))
    SeenLoopVariantSCEVUnknown = true;
  return Expr;
}

const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
  // Only re-write AddRecExprs for this loop.
  if (Expr->getLoop() == L)
    return Expr->getPostIncExpr(SE);
  SeenOtherLoops = true;
  return Expr;
}

bool hasSeenLoopVariantSCEVUnknown() { return SeenLoopVariantSCEVUnknown; }

bool hasSeenOtherLoops() { return SeenOtherLoops; }

4262private:
explicit SCEVPostIncRewriter(const Loop *L, ScalarEvolution &SE)
    : SCEVRewriteVisitor(SE), L(L) {}

const Loop *L;
bool SeenLoopVariantSCEVUnknown = false;
bool SeenOtherLoops = false;
4269};

4271/// This class evaluates the compare condition by matching it against the
4272/// condition of loop latch. If there is a match we assume a true value
4273/// for the condition while building SCEV nodes.
4274class SCEVBackedgeConditionFolder
  : public SCEVRewriteVisitor<SCEVBackedgeConditionFolder> {
4276public:
static const SCEV *rewrite(const SCEV *S, const Loop *L,
                           ScalarEvolution &SE) {
  bool IsPosBECond = false;
  Value *BECond = nullptr;
  if (BasicBlock *Latch = L->getLoopLatch()) {
    BranchInst *BI = dyn_cast<BranchInst>(Latch->getTerminator());
    if (BI && BI->isConditional()) {
      assert(BI->getSuccessor(0) != BI->getSuccessor(1) &&((BI->getSuccessor(0) != BI->getSuccessor(1) &&
 "Both outgoing branches should not target same header!") ? static_cast
<void> (0) : __assert_fail ("BI->getSuccessor(0) != BI->getSuccessor(1) && \"Both outgoing branches should not target same header!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4285, __PRETTY_FUNCTION__))
             "Both outgoing branches should not target same header!")((BI->getSuccessor(0) != BI->getSuccessor(1) &&
 "Both outgoing branches should not target same header!") ? static_cast
<void> (0) : __assert_fail ("BI->getSuccessor(0) != BI->getSuccessor(1) && \"Both outgoing branches should not target same header!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4285, __PRETTY_FUNCTION__));
      BECond = BI->getCondition();
      IsPosBECond = BI->getSuccessor(0) == L->getHeader();
    } else {
      return S;
    }
  }
  SCEVBackedgeConditionFolder Rewriter(L, BECond, IsPosBECond, SE);
  return Rewriter.visit(S);
}

const SCEV *visitUnknown(const SCEVUnknown *Expr) {
  const SCEV *Result = Expr;
  bool InvariantF = SE.isLoopInvariant(Expr, L);

  if (!InvariantF) {
    Instruction *I = cast<Instruction>(Expr->getValue());
    switch (I->getOpcode()) {
    case Instruction::Select: {
      SelectInst *SI = cast<SelectInst>(I);
      Optional<const SCEV *> Res =
          compareWithBackedgeCondition(SI->getCondition());
      if (Res.hasValue()) {
        bool IsOne = cast<SCEVConstant>(Res.getValue())->getValue()->isOne();
        Result = SE.getSCEV(IsOne ? SI->getTrueValue() : SI->getFalseValue());
      }
      break;
    }
    default: {
      Optional<const SCEV *> Res = compareWithBackedgeCondition(I);
      if (Res.hasValue())
        Result = Res.getValue();
      break;
    }
    }
  }
  return Result;
}

4324private:
explicit SCEVBackedgeConditionFolder(const Loop *L, Value *BECond,
                                     bool IsPosBECond, ScalarEvolution &SE)
    : SCEVRewriteVisitor(SE), L(L), BackedgeCond(BECond),
      IsPositiveBECond(IsPosBECond) {}

Optional<const SCEV *> compareWithBackedgeCondition(Value *IC);

const Loop *L;
/// Loop back condition.
Value *BackedgeCond = nullptr;
/// Set to true if loop back is on positive branch condition.
bool IsPositiveBECond;
4337};

4339Optional<const SCEV *>
4340SCEVBackedgeConditionFolder::compareWithBackedgeCondition(Value *IC) {

// If value matches the backedge condition for loop latch,
// then return a constant evolution node based on loopback
// branch taken.
if (BackedgeCond == IC)
  return IsPositiveBECond ? SE.getOne(Type::getInt1Ty(SE.getContext()))
                          : SE.getZero(Type::getInt1Ty(SE.getContext()));
return None;
4349}

4351class SCEVShiftRewriter : public SCEVRewriteVisitor<SCEVShiftRewriter> {
4352public:
static const SCEV *rewrite(const SCEV *S, const Loop *L,
                           ScalarEvolution &SE) {
  SCEVShiftRewriter Rewriter(L, SE);
  const SCEV *Result = Rewriter.visit(S);
  return Rewriter.isValid() ? Result : SE.getCouldNotCompute();
}

const SCEV *visitUnknown(const SCEVUnknown *Expr) {
  // Only allow AddRecExprs for this loop.
  if (!SE.isLoopInvariant(Expr, L))
    Valid = false;
  return Expr;
}

const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
  if (Expr->getLoop() == L && Expr->isAffine())
    return SE.getMinusSCEV(Expr, Expr->getStepRecurrence(SE));
  Valid = false;
  return Expr;
}

bool isValid() { return Valid; }

4376private:
explicit SCEVShiftRewriter(const Loop *L, ScalarEvolution &SE)
    : SCEVRewriteVisitor(SE), L(L) {}

const Loop *L;
bool Valid = true;
4382};

4384} // end anonymous namespace

4386SCEV::NoWrapFlags
4387ScalarEvolution::proveNoWrapViaConstantRanges(const SCEVAddRecExpr *AR) {
if (!AR->isAffine())
  return SCEV::FlagAnyWrap;

using OBO = OverflowingBinaryOperator;

SCEV::NoWrapFlags Result = SCEV::FlagAnyWrap;

if (!AR->hasNoSignedWrap()) {
  ConstantRange AddRecRange = getSignedRange(AR);
  ConstantRange IncRange = getSignedRange(AR->getStepRecurrence(*this));

  auto NSWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
      Instruction::Add, IncRange, OBO::NoSignedWrap);
  if (NSWRegion.contains(AddRecRange))
    Result = ScalarEvolution::setFlags(Result, SCEV::FlagNSW);
}

if (!AR->hasNoUnsignedWrap()) {
  ConstantRange AddRecRange = getUnsignedRange(AR);
  ConstantRange IncRange = getUnsignedRange(AR->getStepRecurrence(*this));

  auto NUWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
      Instruction::Add, IncRange, OBO::NoUnsignedWrap);
  if (NUWRegion.contains(AddRecRange))
    Result = ScalarEvolution::setFlags(Result, SCEV::FlagNUW);
}

return Result;
4416}

4418SCEV::NoWrapFlags
4419ScalarEvolution::proveNoSignedWrapViaInduction(const SCEVAddRecExpr *AR) {
SCEV::NoWrapFlags Result = AR->getNoWrapFlags();

if (AR->hasNoSignedWrap())
  return Result;

if (!AR->isAffine())
  return Result;

const SCEV *Step = AR->getStepRecurrence(*this);
const Loop *L = AR->getLoop();

// Check whether the backedge-taken count is SCEVCouldNotCompute.
// Note that this serves two purposes: It filters out loops that are
// simply not analyzable, and it covers the case where this code is
// being called from within backedge-taken count analysis, such that
// attempting to ask for the backedge-taken count would likely result
// in infinite recursion. In the later case, the analysis code will
// cope with a conservative value, and it will take care to purge
// that value once it has finished.
const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(L);

// Normally, in the cases we can prove no-overflow via a
// backedge guarding condition, we can also compute a backedge
// taken count for the loop.  The exceptions are assumptions and
// guards present in the loop -- SCEV is not great at exploiting
// these to compute max backedge taken counts, but can still use
// these to prove lack of overflow.  Use this fact to avoid
// doing extra work that may not pay off.

if (isa<SCEVCouldNotCompute>(MaxBECount) && !HasGuards &&
    AC.assumptions().empty())
  return Result;

// If the backedge is guarded by a comparison with the pre-inc  value the
// addrec is safe. Also, if the entry is guarded by a comparison with the
// start value and the backedge is guarded by a comparison with the post-inc
// value, the addrec is safe.
ICmpInst::Predicate Pred;
const SCEV *OverflowLimit =
  getSignedOverflowLimitForStep(Step, &Pred, this);
if (OverflowLimit &&
    (isLoopBackedgeGuardedByCond(L, Pred, AR, OverflowLimit) ||
     isKnownOnEveryIteration(Pred, AR, OverflowLimit))) {
  Result = setFlags(Result, SCEV::FlagNSW);
}
return Result;
4466}
4467SCEV::NoWrapFlags
4468ScalarEvolution::proveNoUnsignedWrapViaInduction(const SCEVAddRecExpr *AR) {
SCEV::NoWrapFlags Result = AR->getNoWrapFlags();

if (AR->hasNoUnsignedWrap())
  return Result;

if (!AR->isAffine())
  return Result;

const SCEV *Step = AR->getStepRecurrence(*this);
unsigned BitWidth = getTypeSizeInBits(AR->getType());
const Loop *L = AR->getLoop();

// Check whether the backedge-taken count is SCEVCouldNotCompute.
// Note that this serves two purposes: It filters out loops that are
// simply not analyzable, and it covers the case where this code is
// being called from within backedge-taken count analysis, such that
// attempting to ask for the backedge-taken count would likely result
// in infinite recursion. In the later case, the analysis code will
// cope with a conservative value, and it will take care to purge
// that value once it has finished.
const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(L);

// Normally, in the cases we can prove no-overflow via a
// backedge guarding condition, we can also compute a backedge
// taken count for the loop.  The exceptions are assumptions and
// guards present in the loop -- SCEV is not great at exploiting
// these to compute max backedge taken counts, but can still use
// these to prove lack of overflow.  Use this fact to avoid
// doing extra work that may not pay off.

if (isa<SCEVCouldNotCompute>(MaxBECount) && !HasGuards &&
    AC.assumptions().empty())
  return Result;

// If the backedge is guarded by a comparison with the pre-inc  value the
// addrec is safe. Also, if the entry is guarded by a comparison with the
// start value and the backedge is guarded by a comparison with the post-inc
// value, the addrec is safe.
if (isKnownPositive(Step)) {
  const SCEV *N = getConstant(APInt::getMinValue(BitWidth) -
                              getUnsignedRangeMax(Step));
  if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_ULT, AR, N) ||
      isKnownOnEveryIteration(ICmpInst::ICMP_ULT, AR, N)) {
    Result = setFlags(Result, SCEV::FlagNUW);
  }
}

return Result;
4517}

4519namespace {

4521/// Represents an abstract binary operation.  This may exist as a
4522/// normal instruction or constant expression, or may have been
4523/// derived from an expression tree.
4524struct BinaryOp {
unsigned Opcode;
Value *LHS;
Value *RHS;
bool IsNSW = false;
bool IsNUW = false;
bool IsExact = false;

/// Op is set if this BinaryOp corresponds to a concrete LLVM instruction or
/// constant expression.
Operator *Op = nullptr;

explicit BinaryOp(Operator *Op)
    : Opcode(Op->getOpcode()), LHS(Op->getOperand(0)), RHS(Op->getOperand(1)),
      Op(Op) {
  if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(Op)) {
    IsNSW = OBO->hasNoSignedWrap();
    IsNUW = OBO->hasNoUnsignedWrap();
  }
  if (auto *PEO = dyn_cast<PossiblyExactOperator>(Op))
    IsExact = PEO->isExact();
}

explicit BinaryOp(unsigned Opcode, Value *LHS, Value *RHS, bool IsNSW = false,
                  bool IsNUW = false, bool IsExact = false)
    : Opcode(Opcode), LHS(LHS), RHS(RHS), IsNSW(IsNSW), IsNUW(IsNUW),
      IsExact(IsExact) {}
4551};

4553} // end anonymous namespace

4555/// Try to map \p V into a BinaryOp, and return \c None on failure.
4556static Optional<BinaryOp> MatchBinaryOp(Value *V, DominatorTree &DT) {
auto *Op = dyn_cast<Operator>(V);
if (!Op)
  return None;

// Implementation detail: all the cleverness here should happen without
// creating new SCEV expressions -- our caller knowns tricks to avoid creating
// SCEV expressions when possible, and we should not break that.

switch (Op->getOpcode()) {
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
case Instruction::UDiv:
case Instruction::URem:
case Instruction::And:
case Instruction::Or:
case Instruction::AShr:
case Instruction::Shl:
  return BinaryOp(Op);

case Instruction::Xor:
  if (auto *RHSC = dyn_cast<ConstantInt>(Op->getOperand(1)))
    // If the RHS of the xor is a signmask, then this is just an add.
    // Instcombine turns add of signmask into xor as a strength reduction step.
    if (RHSC->getValue().isSignMask())
      return BinaryOp(Instruction::Add, Op->getOperand(0), Op->getOperand(1));
  return BinaryOp(Op);

case Instruction::LShr:
  // Turn logical shift right of a constant into a unsigned divide.
  if (ConstantInt *SA = dyn_cast<ConstantInt>(Op->getOperand(1))) {
    uint32_t BitWidth = cast<IntegerType>(Op->getType())->getBitWidth();

    // If the shift count is not less than the bitwidth, the result of
    // the shift is undefined. Don't try to analyze it, because the
    // resolution chosen here may differ from the resolution chosen in
    // other parts of the compiler.
    if (SA->getValue().ult(BitWidth)) {
      Constant *X =
          ConstantInt::get(SA->getContext(),
                           APInt::getOneBitSet(BitWidth, SA->getZExtValue()));
      return BinaryOp(Instruction::UDiv, Op->getOperand(0), X);
    }
  }
  return BinaryOp(Op);

case Instruction::ExtractValue: {
  auto *EVI = cast<ExtractValueInst>(Op);
  if (EVI->getNumIndices() != 1 || EVI->getIndices()[0] != 0)
    break;

  auto *WO = dyn_cast<WithOverflowInst>(EVI->getAggregateOperand());
  if (!WO)
    break;

  Instruction::BinaryOps BinOp = WO->getBinaryOp();
  bool Signed = WO->isSigned();
  // TODO: Should add nuw/nsw flags for mul as well.
  if (BinOp == Instruction::Mul || !isOverflowIntrinsicNoWrap(WO, DT))
    return BinaryOp(BinOp, WO->getLHS(), WO->getRHS());

  // Now that we know that all uses of the arithmetic-result component of
  // CI are guarded by the overflow check, we can go ahead and pretend
  // that the arithmetic is non-overflowing.
  return BinaryOp(BinOp, WO->getLHS(), WO->getRHS(),
                  /* IsNSW = */ Signed, /* IsNUW = */ !Signed);
}

default:
  break;
}

// Recognise intrinsic loop.decrement.reg, and as this has exactly the same
// semantics as a Sub, return a binary sub expression.
if (auto *II = dyn_cast<IntrinsicInst>(V))
  if (II->getIntrinsicID() == Intrinsic::loop_decrement_reg)
    return BinaryOp(Instruction::Sub, II->getOperand(0), II->getOperand(1));

return None;
4636}

4638/// Helper function to createAddRecFromPHIWithCasts. We have a phi
4639/// node whose symbolic (unknown) SCEV is \p SymbolicPHI, which is updated via
4640/// the loop backedge by a SCEVAddExpr, possibly also with a few casts on the
4641/// way. This function checks if \p Op, an operand of this SCEVAddExpr,
4642/// follows one of the following patterns:
4643/// Op == (SExt ix (Trunc iy (%SymbolicPHI) to ix) to iy)
4644/// Op == (ZExt ix (Trunc iy (%SymbolicPHI) to ix) to iy)
4645/// If the SCEV expression of \p Op conforms with one of the expected patterns
4646/// we return the type of the truncation operation, and indicate whether the
4647/// truncated type should be treated as signed/unsigned by setting
4648/// \p Signed to true/false, respectively.
4649static Type *isSimpleCastedPHI(const SCEV *Op, const SCEVUnknown *SymbolicPHI,
                             bool &Signed, ScalarEvolution &SE) {
// The case where Op == SymbolicPHI (that is, with no type conversions on
// the way) is handled by the regular add recurrence creating logic and
// would have already been triggered in createAddRecForPHI. Reaching it here
// means that createAddRecFromPHI had failed for this PHI before (e.g.,
// because one of the other operands of the SCEVAddExpr updating this PHI is
// not invariant).
//
// Here we look for the case where Op = (ext(trunc(SymbolicPHI))), and in
// this case predicates that allow us to prove that Op == SymbolicPHI will
// be added.
if (Op == SymbolicPHI)
  return nullptr;

unsigned SourceBits = SE.getTypeSizeInBits(SymbolicPHI->getType());
unsigned NewBits = SE.getTypeSizeInBits(Op->getType());
if (SourceBits != NewBits)
  return nullptr;

const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(Op);
const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(Op);
if (!SExt && !ZExt)
  return nullptr;
const SCEVTruncateExpr *Trunc =
    SExt ? dyn_cast<SCEVTruncateExpr>(SExt->getOperand())
         : dyn_cast<SCEVTruncateExpr>(ZExt->getOperand());
if (!Trunc)
  return nullptr;
const SCEV *X = Trunc->getOperand();
if (X != SymbolicPHI)
  return nullptr;
Signed = SExt != nullptr;
return Trunc->getType();
4683}

4685static const Loop *isIntegerLoopHeaderPHI(const PHINode *PN, LoopInfo &LI) {
if (!PN->getType()->isIntegerTy())
  return nullptr;
const Loop *L = LI.getLoopFor(PN->getParent());
if (!L || L->getHeader() != PN->getParent())
  return nullptr;
return L;
4692}

4694// Analyze \p SymbolicPHI, a SCEV expression of a phi node, and check if the
4695// computation that updates the phi follows the following pattern:
4696//   (SExt/ZExt ix (Trunc iy (%SymbolicPHI) to ix) to iy) + InvariantAccum
4697// which correspond to a phi->trunc->sext/zext->add->phi update chain.
4698// If so, try to see if it can be rewritten as an AddRecExpr under some
4699// Predicates. If successful, return them as a pair. Also cache the results
4700// of the analysis.
4701//
4702// Example usage scenario:
4703//    Say the Rewriter is called for the following SCEV:
4704//         8 * ((sext i32 (trunc i64 %X to i32) to i64) + %Step)
4705//    where:
4706//         %X = phi i64 (%Start, %BEValue)
4707//    It will visitMul->visitAdd->visitSExt->visitTrunc->visitUnknown(%X),
4708//    and call this function with %SymbolicPHI = %X.
4709//
4710//    The analysis will find that the value coming around the backedge has
4711//    the following SCEV:
4712//         BEValue = ((sext i32 (trunc i64 %X to i32) to i64) + %Step)
4713//    Upon concluding that this matches the desired pattern, the function
4714//    will return the pair {NewAddRec, SmallPredsVec} where:
4715//         NewAddRec = {%Start,+,%Step}
4716//         SmallPredsVec = {P1, P2, P3} as follows:
4717//           P1(WrapPred): AR: {trunc(%Start),+,(trunc %Step)}<nsw> Flags: <nssw>
4718//           P2(EqualPred): %Start == (sext i32 (trunc i64 %Start to i32) to i64)
4719//           P3(EqualPred): %Step == (sext i32 (trunc i64 %Step to i32) to i64)
4720//    The returned pair means that SymbolicPHI can be rewritten into NewAddRec
4721//    under the predicates {P1,P2,P3}.
4722//    This predicated rewrite will be cached in PredicatedSCEVRewrites:
4723//         PredicatedSCEVRewrites[{%X,L}] = {NewAddRec, {P1,P2,P3)}
4724//
4725// TODO's:
4726//
4727// 1) Extend the Induction descriptor to also support inductions that involve
4728//    casts: When needed (namely, when we are called in the context of the
4729//    vectorizer induction analysis), a Set of cast instructions will be
4730//    populated by this method, and provided back to isInductionPHI. This is
4731//    needed to allow the vectorizer to properly record them to be ignored by
4732//    the cost model and to avoid vectorizing them (otherwise these casts,
4733//    which are redundant under the runtime overflow checks, will be
4734//    vectorized, which can be costly).
4735//
4736// 2) Support additional induction/PHISCEV patterns: We also want to support
4737//    inductions where the sext-trunc / zext-trunc operations (partly) occur
4738//    after the induction update operation (the induction increment):
4739//
4740//      (Trunc iy (SExt/ZExt ix (%SymbolicPHI + InvariantAccum) to iy) to ix)
4741//    which correspond to a phi->add->trunc->sext/zext->phi update chain.
4742//
4743//      (Trunc iy ((SExt/ZExt ix (%SymbolicPhi) to iy) + InvariantAccum) to ix)
4744//    which correspond to a phi->trunc->add->sext/zext->phi update chain.
4745//
4746// 3) Outline common code with createAddRecFromPHI to avoid duplication.
4747Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>>
4748ScalarEvolution::createAddRecFromPHIWithCastsImpl(const SCEVUnknown *SymbolicPHI) {
SmallVector<const SCEVPredicate *, 3> Predicates;

// *** Part1: Analyze if we have a phi-with-cast pattern for which we can
// return an AddRec expression under some predicate.

auto *PN = cast<PHINode>(SymbolicPHI->getValue());
const Loop *L = isIntegerLoopHeaderPHI(PN, LI);
assert(L && "Expecting an integer loop header phi")((L && "Expecting an integer loop header phi") ? static_cast
<void> (0) : __assert_fail ("L && \"Expecting an integer loop header phi\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4756, __PRETTY_FUNCTION__));

// The loop may have multiple entrances or multiple exits; we can analyze
// this phi as an addrec if it has a unique entry value and a unique
// backedge value.
Value *BEValueV = nullptr, *StartValueV = nullptr;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
  Value *V = PN->getIncomingValue(i);
  if (L->contains(PN->getIncomingBlock(i))) {
    if (!BEValueV) {
      BEValueV = V;
    } else if (BEValueV != V) {
      BEValueV = nullptr;
      break;
    }
  } else if (!StartValueV) {
    StartValueV = V;
  } else if (StartValueV != V) {
    StartValueV = nullptr;
    break;
  }
}
if (!BEValueV || !StartValueV)
  return None;

const SCEV *BEValue = getSCEV(BEValueV);

// If the value coming around the backedge is an add with the symbolic
// value we just inserted, possibly with casts that we can ignore under
// an appropriate runtime guard, then we found a simple induction variable!
const auto *Add = dyn_cast<SCEVAddExpr>(BEValue);
if (!Add)
  return None;

// If there is a single occurrence of the symbolic value, possibly
// casted, replace it with a recurrence.
unsigned FoundIndex = Add->getNumOperands();
Type *TruncTy = nullptr;
bool Signed;
for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i)
  if ((TruncTy =
           isSimpleCastedPHI(Add->getOperand(i), SymbolicPHI, Signed, *this)))
    if (FoundIndex == e) {
      FoundIndex = i;
      break;
    }

if (FoundIndex == Add->getNumOperands())
  return None;

// Create an add with everything but the specified operand.
SmallVector<const SCEV *, 8> Ops;
for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i)
  if (i != FoundIndex)
    Ops.push_back(Add->getOperand(i));
const SCEV *Accum = getAddExpr(Ops);

// The runtime checks will not be valid if the step amount is
// varying inside the loop.
if (!isLoopInvariant(Accum, L))
  return None;

// *** Part2: Create the predicates

// Analysis was successful: we have a phi-with-cast pattern for which we
// can return an AddRec expression under the following predicates:
//
// P1: A Wrap predicate that guarantees that Trunc(Start) + i*Trunc(Accum)
//     fits within the truncated type (does not overflow) for i = 0 to n-1.
// P2: An Equal predicate that guarantees that
//     Start = (Ext ix (Trunc iy (Start) to ix) to iy)
// P3: An Equal predicate that guarantees that
//     Accum = (Ext ix (Trunc iy (Accum) to ix) to iy)
//
// As we next prove, the above predicates guarantee that:
//     Start + i*Accum = (Ext ix (Trunc iy ( Start + i*Accum ) to ix) to iy)
//
//
// More formally, we want to prove that:
//     Expr(i+1) = Start + (i+1) * Accum
//               = (Ext ix (Trunc iy (Expr(i)) to ix) to iy) + Accum
//
// Given that:
// 1) Expr(0) = Start
// 2) Expr(1) = Start + Accum
//            = (Ext ix (Trunc iy (Start) to ix) to iy) + Accum :: from P2
// 3) Induction hypothesis (step i):
//    Expr(i) = (Ext ix (Trunc iy (Expr(i-1)) to ix) to iy) + Accum
//
// Proof:
//  Expr(i+1) =
//   = Start + (i+1)*Accum
//   = (Start + i*Accum) + Accum
//   = Expr(i) + Accum
//   = (Ext ix (Trunc iy (Expr(i-1)) to ix) to iy) + Accum + Accum
//                                                             :: from step i
//
//   = (Ext ix (Trunc iy (Start + (i-1)*Accum) to ix) to iy) + Accum + Accum
//
//   = (Ext ix (Trunc iy (Start + (i-1)*Accum) to ix) to iy)
//     + (Ext ix (Trunc iy (Accum) to ix) to iy)
//     + Accum                                                     :: from P3
//
//   = (Ext ix (Trunc iy ((Start + (i-1)*Accum) + Accum) to ix) to iy)
//     + Accum                            :: from P1: Ext(x)+Ext(y)=>Ext(x+y)
//
//   = (Ext ix (Trunc iy (Start + i*Accum) to ix) to iy) + Accum
//   = (Ext ix (Trunc iy (Expr(i)) to ix) to iy) + Accum
//
// By induction, the same applies to all iterations 1<=i<n:
//

// Create a truncated addrec for which we will add a no overflow check (P1).
const SCEV *StartVal = getSCEV(StartValueV);
const SCEV *PHISCEV =
    getAddRecExpr(getTruncateExpr(StartVal, TruncTy),
                  getTruncateExpr(Accum, TruncTy), L, SCEV::FlagAnyWrap);

// PHISCEV can be either a SCEVConstant or a SCEVAddRecExpr.
// ex: If truncated Accum is 0 and StartVal is a constant, then PHISCEV
// will be constant.
//
//  If PHISCEV is a constant, then P1 degenerates into P2 or P3, so we don't
// add P1.
if (const auto *AR = dyn_cast<SCEVAddRecExpr>(PHISCEV)) {
  SCEVWrapPredicate::IncrementWrapFlags AddedFlags =
      Signed ? SCEVWrapPredicate::IncrementNSSW
             : SCEVWrapPredicate::IncrementNUSW;
  const SCEVPredicate *AddRecPred = getWrapPredicate(AR, AddedFlags);
  Predicates.push_back(AddRecPred);
}

// Create the Equal Predicates P2,P3:

// It is possible that the predicates P2 and/or P3 are computable at
// compile time due to StartVal and/or Accum being constants.
// If either one is, then we can check that now and escape if either P2
// or P3 is false.

// Construct the extended SCEV: (Ext ix (Trunc iy (Expr) to ix) to iy)
// for each of StartVal and Accum
auto getExtendedExpr = [&](const SCEV *Expr,
                           bool CreateSignExtend) -> const SCEV * {
  assert(isLoopInvariant(Expr, L) && "Expr is expected to be invariant")((isLoopInvariant(Expr, L) && "Expr is expected to be invariant"
) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(Expr, L) && \"Expr is expected to be invariant\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4899, __PRETTY_FUNCTION__));
  const SCEV *TruncatedExpr = getTruncateExpr(Expr, TruncTy);
  const SCEV *ExtendedExpr =
      CreateSignExtend ? getSignExtendExpr(TruncatedExpr, Expr->getType())
                       : getZeroExtendExpr(TruncatedExpr, Expr->getType());
  return ExtendedExpr;
};

// Given:
//  ExtendedExpr = (Ext ix (Trunc iy (Expr) to ix) to iy
//               = getExtendedExpr(Expr)
// Determine whether the predicate P: Expr == ExtendedExpr
// is known to be false at compile time
auto PredIsKnownFalse = [&](const SCEV *Expr,
                            const SCEV *ExtendedExpr) -> bool {
  return Expr != ExtendedExpr &&
         isKnownPredicate(ICmpInst::ICMP_NE, Expr, ExtendedExpr);
};

const SCEV *StartExtended = getExtendedExpr(StartVal, Signed);
if (PredIsKnownFalse(StartVal, StartExtended)) {
  LLVM_DEBUG(dbgs() << "P2 is compile-time false\n";)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << "P2 is compile-time false\n"
;; } } while (false);
  return None;
}

// The Step is always Signed (because the overflow checks are either
// NSSW or NUSW)
const SCEV *AccumExtended = getExtendedExpr(Accum, /*CreateSignExtend=*/true);
if (PredIsKnownFalse(Accum, AccumExtended)) {
  LLVM_DEBUG(dbgs() << "P3 is compile-time false\n";)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << "P3 is compile-time false\n"
;; } } while (false);
  return None;
}

auto AppendPredicate = [&](const SCEV *Expr,
                           const SCEV *ExtendedExpr) -> void {
  if (Expr != ExtendedExpr &&
      !isKnownPredicate(ICmpInst::ICMP_EQ, Expr, ExtendedExpr)) {
    const SCEVPredicate *Pred = getEqualPredicate(Expr, ExtendedExpr);
    LLVM_DEBUG(dbgs() << "Added Predicate: " << *Pred)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << "Added Predicate: " <<
 *Pred; } } while (false);
    Predicates.push_back(Pred);
  }
};

AppendPredicate(StartVal, StartExtended);
AppendPredicate(Accum, AccumExtended);

// *** Part3: Predicates are ready. Now go ahead and create the new addrec in
// which the casts had been folded away. The caller can rewrite SymbolicPHI
// into NewAR if it will also add the runtime overflow checks specified in
// Predicates.
auto *NewAR = getAddRecExpr(StartVal, Accum, L, SCEV::FlagAnyWrap);

std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>> PredRewrite =
    std::make_pair(NewAR, Predicates);
// Remember the result of the analysis for this SCEV at this locayyytion.
PredicatedSCEVRewrites[{SymbolicPHI, L}] = PredRewrite;
return PredRewrite;
4956}

4958Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>>
4959ScalarEvolution::createAddRecFromPHIWithCasts(const SCEVUnknown *SymbolicPHI) {
auto *PN = cast<PHINode>(SymbolicPHI->getValue());
const Loop *L = isIntegerLoopHeaderPHI(PN, LI);
if (!L)
  return None;

// Check to see if we already analyzed this PHI.
auto I = PredicatedSCEVRewrites.find({SymbolicPHI, L});
if (I != PredicatedSCEVRewrites.end()) {
  std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>> Rewrite =
      I->second;
  // Analysis was done before and failed to create an AddRec:
  if (Rewrite.first == SymbolicPHI)
    return None;
  // Analysis was done before and succeeded to create an AddRec under
  // a predicate:
  assert(isa<SCEVAddRecExpr>(Rewrite.first) && "Expected an AddRec")((isa<SCEVAddRecExpr>(Rewrite.first) && "Expected an AddRec"
) ? static_cast<void> (0) : __assert_fail ("isa<SCEVAddRecExpr>(Rewrite.first) && \"Expected an AddRec\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4975, __PRETTY_FUNCTION__));
  assert(!(Rewrite.second).empty() && "Expected to find Predicates")((!(Rewrite.second).empty() && "Expected to find Predicates"
) ? static_cast<void> (0) : __assert_fail ("!(Rewrite.second).empty() && \"Expected to find Predicates\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 4976, __PRETTY_FUNCTION__));
  return Rewrite;
}

Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>>
  Rewrite = createAddRecFromPHIWithCastsImpl(SymbolicPHI);

// Record in the cache that the analysis failed
if (!Rewrite) {
  SmallVector<const SCEVPredicate *, 3> Predicates;
  PredicatedSCEVRewrites[{SymbolicPHI, L}] = {SymbolicPHI, Predicates};
  return None;
}

return Rewrite;
4991}

4993// FIXME: This utility is currently required because the Rewriter currently
4994// does not rewrite this expression:
4995// {0, +, (sext ix (trunc iy to ix) to iy)}
4996// into {0, +, %step},
4997// even when the following Equal predicate exists:
4998// "%step == (sext ix (trunc iy to ix) to iy)".
4999bool PredicatedScalarEvolution::areAddRecsEqualWithPreds(
  const SCEVAddRecExpr *AR1, const SCEVAddRecExpr *AR2) const {
if (AR1 == AR2)
  return true;

auto areExprsEqual = [&](const SCEV *Expr1, const SCEV *Expr2) -> bool {
  if (Expr1 != Expr2 && !Preds.implies(SE.getEqualPredicate(Expr1, Expr2)) &&
      !Preds.implies(SE.getEqualPredicate(Expr2, Expr1)))
    return false;
  return true;
};

if (!areExprsEqual(AR1->getStart(), AR2->getStart()) ||
    !areExprsEqual(AR1->getStepRecurrence(SE), AR2->getStepRecurrence(SE)))
  return false;
return true;
5015}

5017/// A helper function for createAddRecFromPHI to handle simple cases.
5018///
5019/// This function tries to find an AddRec expression for the simplest (yet most
5020/// common) cases: PN = PHI(Start, OP(Self, LoopInvariant)).
5021/// If it fails, createAddRecFromPHI will use a more general, but slow,
5022/// technique for finding the AddRec expression.
5023const SCEV *ScalarEvolution::createSimpleAffineAddRec(PHINode *PN,
                                                    Value *BEValueV,
                                                    Value *StartValueV) {
const Loop *L = LI.getLoopFor(PN->getParent());
assert(L && L->getHeader() == PN->getParent())((L && L->getHeader() == PN->getParent()) ? static_cast
<void> (0) : __assert_fail ("L && L->getHeader() == PN->getParent()"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5027, __PRETTY_FUNCTION__));
assert(BEValueV && StartValueV)((BEValueV && StartValueV) ? static_cast<void> (
0) : __assert_fail ("BEValueV && StartValueV", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5028, __PRETTY_FUNCTION__));

auto BO = MatchBinaryOp(BEValueV, DT);
if (!BO)
  return nullptr;

if (BO->Opcode != Instruction::Add)
  return nullptr;

const SCEV *Accum = nullptr;
if (BO->LHS == PN && L->isLoopInvariant(BO->RHS))
  Accum = getSCEV(BO->RHS);
else if (BO->RHS == PN && L->isLoopInvariant(BO->LHS))
  Accum = getSCEV(BO->LHS);

if (!Accum)
  return nullptr;

SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap;
if (BO->IsNUW)
  Flags = setFlags(Flags, SCEV::FlagNUW);
if (BO->IsNSW)
  Flags = setFlags(Flags, SCEV::FlagNSW);

const SCEV *StartVal = getSCEV(StartValueV);
const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags);

ValueExprMap[SCEVCallbackVH(PN, this)] = PHISCEV;

// We can add Flags to the post-inc expression only if we
// know that it is *undefined behavior* for BEValueV to
// overflow.
if (auto *BEInst = dyn_cast<Instruction>(BEValueV))
  if (isLoopInvariant(Accum, L) && isAddRecNeverPoison(BEInst, L))
    (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags);

return PHISCEV;
5065}

5067const SCEV *ScalarEvolution::createAddRecFromPHI(PHINode *PN) {
const Loop *L = LI.getLoopFor(PN->getParent());
if (!L || L->getHeader() != PN->getParent())
  return nullptr;

// The loop may have multiple entrances or multiple exits; we can analyze
// this phi as an addrec if it has a unique entry value and a unique
// backedge value.
Value *BEValueV = nullptr, *StartValueV = nullptr;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
  Value *V = PN->getIncomingValue(i);
  if (L->contains(PN->getIncomingBlock(i))) {
    if (!BEValueV) {
      BEValueV = V;
    } else if (BEValueV != V) {
      BEValueV = nullptr;
      break;
    }
  } else if (!StartValueV) {
    StartValueV = V;
  } else if (StartValueV != V) {
    StartValueV = nullptr;
    break;
  }
}
if (!BEValueV || !StartValueV)
  return nullptr;

assert(ValueExprMap.find_as(PN) == ValueExprMap.end() &&((ValueExprMap.find_as(PN) == ValueExprMap.end() && "PHI node already processed?"
) ? static_cast<void> (0) : __assert_fail ("ValueExprMap.find_as(PN) == ValueExprMap.end() && \"PHI node already processed?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5096, __PRETTY_FUNCTION__))
       "PHI node already processed?")((ValueExprMap.find_as(PN) == ValueExprMap.end() && "PHI node already processed?"
) ? static_cast<void> (0) : __assert_fail ("ValueExprMap.find_as(PN) == ValueExprMap.end() && \"PHI node already processed?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5096, __PRETTY_FUNCTION__));

// First, try to find AddRec expression without creating a fictituos symbolic
// value for PN.
if (auto *S = createSimpleAffineAddRec(PN, BEValueV, StartValueV))
  return S;

// Handle PHI node value symbolically.
const SCEV *SymbolicName = getUnknown(PN);
ValueExprMap.insert({SCEVCallbackVH(PN, this), SymbolicName});

// Using this symbolic name for the PHI, analyze the value coming around
// the back-edge.
const SCEV *BEValue = getSCEV(BEValueV);

// NOTE: If BEValue is loop invariant, we know that the PHI node just
// has a special value for the first iteration of the loop.

// If the value coming around the backedge is an add with the symbolic
// value we just inserted, then we found a simple induction variable!
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(BEValue)) {
  // If there is a single occurrence of the symbolic value, replace it
  // with a recurrence.
  unsigned FoundIndex = Add->getNumOperands();
  for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i)
    if (Add->getOperand(i) == SymbolicName)
      if (FoundIndex == e) {
        FoundIndex = i;
        break;
      }

  if (FoundIndex != Add->getNumOperands()) {
    // Create an add with everything but the specified operand.
    SmallVector<const SCEV *, 8> Ops;
    for (unsigned i = 0, e = Add->getNumOperands(); i != e; ++i)
      if (i != FoundIndex)
        Ops.push_back(SCEVBackedgeConditionFolder::rewrite(Add->getOperand(i),
                                                           L, *this));
    const SCEV *Accum = getAddExpr(Ops);

    // This is not a valid addrec if the step amount is varying each
    // loop iteration, but is not itself an addrec in this loop.
    if (isLoopInvariant(Accum, L) ||
        (isa<SCEVAddRecExpr>(Accum) &&
         cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) {
      SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap;

      if (auto BO = MatchBinaryOp(BEValueV, DT)) {
        if (BO->Opcode == Instruction::Add && BO->LHS == PN) {
          if (BO->IsNUW)
            Flags = setFlags(Flags, SCEV::FlagNUW);
          if (BO->IsNSW)
            Flags = setFlags(Flags, SCEV::FlagNSW);
        }
      } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(BEValueV)) {
        // If the increment is an inbounds GEP, then we know the address
        // space cannot be wrapped around. We cannot make any guarantee
        // about signed or unsigned overflow because pointers are
        // unsigned but we may have a negative index from the base
        // pointer. We can guarantee that no unsigned wrap occurs if the
        // indices form a positive value.
        if (GEP->isInBounds() && GEP->getOperand(0) == PN) {
          Flags = setFlags(Flags, SCEV::FlagNW);

          const SCEV *Ptr = getSCEV(GEP->getPointerOperand());
          if (isKnownPositive(getMinusSCEV(getSCEV(GEP), Ptr)))
            Flags = setFlags(Flags, SCEV::FlagNUW);
        }

        // We cannot transfer nuw and nsw flags from subtraction
        // operations -- sub nuw X, Y is not the same as add nuw X, -Y
        // for instance.
      }

      const SCEV *StartVal = getSCEV(StartValueV);
      const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags);

      // Okay, for the entire analysis of this edge we assumed the PHI
      // to be symbolic.  We now need to go back and purge all of the
      // entries for the scalars that use the symbolic expression.
      forgetSymbolicName(PN, SymbolicName);
      ValueExprMap[SCEVCallbackVH(PN, this)] = PHISCEV;

      // We can add Flags to the post-inc expression only if we
      // know that it is *undefined behavior* for BEValueV to
      // overflow.
      if (auto *BEInst = dyn_cast<Instruction>(BEValueV))
        if (isLoopInvariant(Accum, L) && isAddRecNeverPoison(BEInst, L))
          (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags);

      return PHISCEV;
    }
  }
} else {
  // Otherwise, this could be a loop like this:
  //     i = 0;  for (j = 1; ..; ++j) { ....  i = j; }
  // In this case, j = {1,+,1}  and BEValue is j.
  // Because the other in-value of i (0) fits the evolution of BEValue
  // i really is an addrec evolution.
  //
  // We can generalize this saying that i is the shifted value of BEValue
  // by one iteration:
  //   PHI(f(0), f({1,+,1})) --> f({0,+,1})
  const SCEV *Shifted = SCEVShiftRewriter::rewrite(BEValue, L, *this);
  const SCEV *Start = SCEVInitRewriter::rewrite(Shifted, L, *this, false);
  if (Shifted != getCouldNotCompute() &&
      Start != getCouldNotCompute()) {
    const SCEV *StartVal = getSCEV(StartValueV);
    if (Start == StartVal) {
      // Okay, for the entire analysis of this edge we assumed the PHI
      // to be symbolic.  We now need to go back and purge all of the
      // entries for the scalars that use the symbolic expression.
      forgetSymbolicName(PN, SymbolicName);
      ValueExprMap[SCEVCallbackVH(PN, this)] = Shifted;
      return Shifted;
    }
  }
}

// Remove the temporary PHI node SCEV that has been inserted while intending
// to create an AddRecExpr for this PHI node. We can not keep this temporary
// as it will prevent later (possibly simpler) SCEV expressions to be added
// to the ValueExprMap.
eraseValueFromMap(PN);

return nullptr;
5222}

5224// Checks if the SCEV S is available at BB.  S is considered available at BB
5225// if S can be materialized at BB without introducing a fault.
5226static bool IsAvailableOnEntry(const Loop *L, DominatorTree &DT, const SCEV *S,
                             BasicBlock *BB) {
struct CheckAvailable {
  bool TraversalDone = false;
  bool Available = true;

  const Loop *L = nullptr;  // The loop BB is in (can be nullptr)
  BasicBlock *BB = nullptr;
  DominatorTree &DT;

  CheckAvailable(const Loop *L, BasicBlock *BB, DominatorTree &DT)
    : L(L), BB(BB), DT(DT) {}

  bool setUnavailable() {
    TraversalDone = true;
    Available = false;
    return false;
  }

  bool follow(const SCEV *S) {
    switch (S->getSCEVType()) {
    case scConstant:
    case scPtrToInt:
    case scTruncate:
    case scZeroExtend:
    case scSignExtend:
    case scAddExpr:
    case scMulExpr:
    case scUMaxExpr:
    case scSMaxExpr:
    case scUMinExpr:
    case scSMinExpr:
      // These expressions are available if their operand(s) is/are.
      return true;

    case scAddRecExpr: {
      // We allow add recurrences that are on the loop BB is in, or some
      // outer loop.  This guarantees availability because the value of the
      // add recurrence at BB is simply the "current" value of the induction
      // variable.  We can relax this in the future; for instance an add
      // recurrence on a sibling dominating loop is also available at BB.
      const auto *ARLoop = cast<SCEVAddRecExpr>(S)->getLoop();
      if (L && (ARLoop == L || ARLoop->contains(L)))
        return true;

      return setUnavailable();
    }

    case scUnknown: {
      // For SCEVUnknown, we check for simple dominance.
      const auto *SU = cast<SCEVUnknown>(S);
      Value *V = SU->getValue();

      if (isa<Argument>(V))
        return false;

      if (isa<Instruction>(V) && DT.dominates(cast<Instruction>(V), BB))
        return false;

      return setUnavailable();
    }

    case scUDivExpr:
    case scCouldNotCompute:
      // We do not try to smart about these at all.
      return setUnavailable();
    }
    llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5293);
  }

  bool isDone() { return TraversalDone; }
};

CheckAvailable CA(L, BB, DT);
SCEVTraversal<CheckAvailable> ST(CA);

ST.visitAll(S);
return CA.Available;
5304}

5306// Try to match a control flow sequence that branches out at BI and merges back
5307// at Merge into a "C ? LHS : RHS" select pattern.  Return true on a successful
5308// match.
5309static bool BrPHIToSelect(DominatorTree &DT, BranchInst *BI, PHINode *Merge,
                        Value *&C, Value *&LHS, Value *&RHS) {
C = BI->getCondition();

BasicBlockEdge LeftEdge(BI->getParent(), BI->getSuccessor(0));
BasicBlockEdge RightEdge(BI->getParent(), BI->getSuccessor(1));

if (!LeftEdge.isSingleEdge())
  return false;

assert(RightEdge.isSingleEdge() && "Follows from LeftEdge.isSingleEdge()")((RightEdge.isSingleEdge() && "Follows from LeftEdge.isSingleEdge()"
) ? static_cast<void> (0) : __assert_fail ("RightEdge.isSingleEdge() && \"Follows from LeftEdge.isSingleEdge()\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5319, __PRETTY_FUNCTION__));

Use &LeftUse = Merge->getOperandUse(0);
Use &RightUse = Merge->getOperandUse(1);

if (DT.dominates(LeftEdge, LeftUse) && DT.dominates(RightEdge, RightUse)) {
  LHS = LeftUse;
  RHS = RightUse;
  return true;
}

if (DT.dominates(LeftEdge, RightUse) && DT.dominates(RightEdge, LeftUse)) {
  LHS = RightUse;
  RHS = LeftUse;
  return true;
}

return false;
5337}

5339const SCEV *ScalarEvolution::createNodeFromSelectLikePHI(PHINode *PN) {
auto IsReachable =
    [&](BasicBlock *BB) { return DT.isReachableFromEntry(BB); };
if (PN->getNumIncomingValues() == 2 && all_of(PN->blocks(), IsReachable)) {
  const Loop *L = LI.getLoopFor(PN->getParent());

  // We don't want to break LCSSA, even in a SCEV expression tree.
  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
    if (LI.getLoopFor(PN->getIncomingBlock(i)) != L)
      return nullptr;

  // Try to match
  //
  //  br %cond, label %left, label %right
  // left:
  //  br label %merge
  // right:
  //  br label %merge
  // merge:
  //  V = phi [ %x, %left ], [ %y, %right ]
  //
  // as "select %cond, %x, %y"

  BasicBlock *IDom = DT[PN->getParent()]->getIDom()->getBlock();
  assert(IDom && "At least the entry block should dominate PN")((IDom && "At least the entry block should dominate PN"
) ? static_cast<void> (0) : __assert_fail ("IDom && \"At least the entry block should dominate PN\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5363, __PRETTY_FUNCTION__));

  auto *BI = dyn_cast<BranchInst>(IDom->getTerminator());
  Value *Cond = nullptr, *LHS = nullptr, *RHS = nullptr;

  if (BI && BI->isConditional() &&
      BrPHIToSelect(DT, BI, PN, Cond, LHS, RHS) &&
      IsAvailableOnEntry(L, DT, getSCEV(LHS), PN->getParent()) &&
      IsAvailableOnEntry(L, DT, getSCEV(RHS), PN->getParent()))
    return createNodeForSelectOrPHI(PN, Cond, LHS, RHS);
}

return nullptr;
5376}

5378const SCEV *ScalarEvolution::createNodeForPHI(PHINode *PN) {
if (const SCEV *S = createAddRecFromPHI(PN))
  return S;

if (const SCEV *S = createNodeFromSelectLikePHI(PN))
  return S;

// If the PHI has a single incoming value, follow that value, unless the
// PHI's incoming blocks are in a different loop, in which case doing so
// risks breaking LCSSA form. Instcombine would normally zap these, but
// it doesn't have DominatorTree information, so it may miss cases.
if (Value *V = SimplifyInstruction(PN, {getDataLayout(), &TLI, &DT, &AC}))
  if (LI.replacementPreservesLCSSAForm(PN, V))
    return getSCEV(V);

// If it's not a loop phi, we can't handle it yet.
return getUnknown(PN);
5395}

5397const SCEV *ScalarEvolution::createNodeForSelectOrPHI(Instruction *I,
                                                    Value *Cond,
                                                    Value *TrueVal,
                                                    Value *FalseVal) {
// Handle "constant" branch or select. This can occur for instance when a
// loop pass transforms an inner loop and moves on to process the outer loop.
if (auto *CI = dyn_cast<ConstantInt>(Cond))
  return getSCEV(CI->isOne() ? TrueVal : FalseVal);

// Try to match some simple smax or umax patterns.
auto *ICI = dyn_cast<ICmpInst>(Cond);
if (!ICI)
  return getUnknown(I);

Value *LHS = ICI->getOperand(0);
Value *RHS = ICI->getOperand(1);

switch (ICI->getPredicate()) {
case ICmpInst::ICMP_SLT:
case ICmpInst::ICMP_SLE:
  std::swap(LHS, RHS);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_SGT:
case ICmpInst::ICMP_SGE:
  // a >s b ? a+x : b+x  ->  smax(a, b)+x
  // a >s b ? b+x : a+x  ->  smin(a, b)+x
  if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType())) {
    const SCEV *LS = getNoopOrSignExtend(getSCEV(LHS), I->getType());
    const SCEV *RS = getNoopOrSignExtend(getSCEV(RHS), I->getType());
    const SCEV *LA = getSCEV(TrueVal);
    const SCEV *RA = getSCEV(FalseVal);
    const SCEV *LDiff = getMinusSCEV(LA, LS);
    const SCEV *RDiff = getMinusSCEV(RA, RS);
    if (LDiff == RDiff)
      return getAddExpr(getSMaxExpr(LS, RS), LDiff);
    LDiff = getMinusSCEV(LA, RS);
    RDiff = getMinusSCEV(RA, LS);
    if (LDiff == RDiff)
      return getAddExpr(getSMinExpr(LS, RS), LDiff);
  }
  break;
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_ULE:
  std::swap(LHS, RHS);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_UGE:
  // a >u b ? a+x : b+x  ->  umax(a, b)+x
  // a >u b ? b+x : a+x  ->  umin(a, b)+x
  if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType())) {
    const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType());
    const SCEV *RS = getNoopOrZeroExtend(getSCEV(RHS), I->getType());
    const SCEV *LA = getSCEV(TrueVal);
    const SCEV *RA = getSCEV(FalseVal);
    const SCEV *LDiff = getMinusSCEV(LA, LS);
    const SCEV *RDiff = getMinusSCEV(RA, RS);
    if (LDiff == RDiff)
      return getAddExpr(getUMaxExpr(LS, RS), LDiff);
    LDiff = getMinusSCEV(LA, RS);
    RDiff = getMinusSCEV(RA, LS);
    if (LDiff == RDiff)
      return getAddExpr(getUMinExpr(LS, RS), LDiff);
  }
  break;
case ICmpInst::ICMP_NE:
  // n != 0 ? n+x : 1+x  ->  umax(n, 1)+x
  if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType()) &&
      isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isZero()) {
    const SCEV *One = getOne(I->getType());
    const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType());
    const SCEV *LA = getSCEV(TrueVal);
    const SCEV *RA = getSCEV(FalseVal);
    const SCEV *LDiff = getMinusSCEV(LA, LS);
    const SCEV *RDiff = getMinusSCEV(RA, One);
    if (LDiff == RDiff)
      return getAddExpr(getUMaxExpr(One, LS), LDiff);
  }
  break;
case ICmpInst::ICMP_EQ:
  // n == 0 ? 1+x : n+x  ->  umax(n, 1)+x
  if (getTypeSizeInBits(LHS->getType()) <= getTypeSizeInBits(I->getType()) &&
      isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isZero()) {
    const SCEV *One = getOne(I->getType());
    const SCEV *LS = getNoopOrZeroExtend(getSCEV(LHS), I->getType());
    const SCEV *LA = getSCEV(TrueVal);
    const SCEV *RA = getSCEV(FalseVal);
    const SCEV *LDiff = getMinusSCEV(LA, One);
    const SCEV *RDiff = getMinusSCEV(RA, LS);
    if (LDiff == RDiff)
      return getAddExpr(getUMaxExpr(One, LS), LDiff);
  }
  break;
default:
  break;
}

return getUnknown(I);
5494}

5496/// Expand GEP instructions into add and multiply operations. This allows them
5497/// to be analyzed by regular SCEV code.
5498const SCEV *ScalarEvolution::createNodeForGEP(GEPOperator *GEP) {
// Don't attempt to analyze GEPs over unsized objects.
if (!GEP->getSourceElementType()->isSized())
  return getUnknown(GEP);

SmallVector<const SCEV *, 4> IndexExprs;
for (auto Index = GEP->idx_begin(); Index != GEP->idx_end(); ++Index)
  IndexExprs.push_back(getSCEV(*Index));
return getGEPExpr(GEP, IndexExprs);
5507}

5509uint32_t ScalarEvolution::GetMinTrailingZerosImpl(const SCEV *S) {
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S))
  return C->getAPInt().countTrailingZeros();

if (const SCEVPtrToIntExpr *I = dyn_cast<SCEVPtrToIntExpr>(S))
  return GetMinTrailingZeros(I->getOperand());

if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S))
  return std::min(GetMinTrailingZeros(T->getOperand()),
                  (uint32_t)getTypeSizeInBits(T->getType()));

if (const SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S)) {
  uint32_t OpRes = GetMinTrailingZeros(E->getOperand());
  return OpRes == getTypeSizeInBits(E->getOperand()->getType())
             ? getTypeSizeInBits(E->getType())
             : OpRes;
}

if (const SCEVSignExtendExpr *E = dyn_cast<SCEVSignExtendExpr>(S)) {
  uint32_t OpRes = GetMinTrailingZeros(E->getOperand());
  return OpRes == getTypeSizeInBits(E->getOperand()->getType())
             ? getTypeSizeInBits(E->getType())
             : OpRes;
}

if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) {
  // The result is the min of all operands results.
  uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0));
  for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i)
    MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i)));
  return MinOpRes;
}

if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) {
  // The result is the sum of all operands results.
  uint32_t SumOpRes = GetMinTrailingZeros(M->getOperand(0));
  uint32_t BitWidth = getTypeSizeInBits(M->getType());
  for (unsigned i = 1, e = M->getNumOperands();
       SumOpRes != BitWidth && i != e; ++i)
    SumOpRes =
        std::min(SumOpRes + GetMinTrailingZeros(M->getOperand(i)), BitWidth);
  return SumOpRes;
}

if (const SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
  // The result is the min of all operands results.
  uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0));
  for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i)
    MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i)));
  return MinOpRes;
}

if (const SCEVSMaxExpr *M = dyn_cast<SCEVSMaxExpr>(S)) {
  // The result is the min of all operands results.
  uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0));
  for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i)
    MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i)));
  return MinOpRes;
}

if (const SCEVUMaxExpr *M = dyn_cast<SCEVUMaxExpr>(S)) {
  // The result is the min of all operands results.
  uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0));
  for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i)
    MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i)));
  return MinOpRes;
}

if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
  // For a SCEVUnknown, ask ValueTracking.
  KnownBits Known = computeKnownBits(U->getValue(), getDataLayout(), 0, &AC, nullptr, &DT);
  return Known.countMinTrailingZeros();
}

// SCEVUDivExpr
return 0;
5585}

5587uint32_t ScalarEvolution::GetMinTrailingZeros(const SCEV *S) {
auto I = MinTrailingZerosCache.find(S);
if (I != MinTrailingZerosCache.end())
  return I->second;

uint32_t Result = GetMinTrailingZerosImpl(S);
auto InsertPair = MinTrailingZerosCache.insert({S, Result});
assert(InsertPair.second && "Should insert a new key")((InsertPair.second && "Should insert a new key") ? static_cast
<void> (0) : __assert_fail ("InsertPair.second && \"Should insert a new key\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5594, __PRETTY_FUNCTION__));
return InsertPair.first->second;
5596}

5598/// Helper method to assign a range to V from metadata present in the IR.
5599static Optional<ConstantRange> GetRangeFromMetadata(Value *V) {
if (Instruction *I = dyn_cast<Instruction>(V))
  if (MDNode *MD = I->getMetadata(LLVMContext::MD_range))
    return getConstantRangeFromMetadata(*MD);

return None;
5605}

5607void ScalarEvolution::setNoWrapFlags(SCEVAddRecExpr *AddRec,
                                   SCEV::NoWrapFlags Flags) {
if (AddRec->getNoWrapFlags(Flags) != Flags) {
  AddRec->setNoWrapFlags(Flags);
  UnsignedRanges.erase(AddRec);
  SignedRanges.erase(AddRec);
}
5614}

5616/// Determine the range for a particular SCEV.  If SignHint is
5617/// HINT_RANGE_UNSIGNED (resp. HINT_RANGE_SIGNED) then getRange prefers ranges
5618/// with a "cleaner" unsigned (resp. signed) representation.
5619const ConstantRange &
5620ScalarEvolution::getRangeRef(const SCEV *S,
                           ScalarEvolution::RangeSignHint SignHint) {
DenseMap<const SCEV *, ConstantRange> &Cache =
    SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED ? UnsignedRanges
                                                     : SignedRanges;
ConstantRange::PreferredRangeType RangeType =
    SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED
        ? ConstantRange::Unsigned : ConstantRange::Signed;

// See if we've computed this range already.
DenseMap<const SCEV *, ConstantRange>::iterator I = Cache.find(S);
if (I != Cache.end())
  return I->second;

if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S))
  return setRange(C, SignHint, ConstantRange(C->getAPInt()));

unsigned BitWidth = getTypeSizeInBits(S->getType());
ConstantRange ConservativeResult(BitWidth, /*isFullSet=*/true);
using OBO = OverflowingBinaryOperator;

// If the value has known zeros, the maximum value will have those known zeros
// as well.
uint32_t TZ = GetMinTrailingZeros(S);
if (TZ != 0) {
  if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED)
    ConservativeResult =
        ConstantRange(APInt::getMinValue(BitWidth),
                      APInt::getMaxValue(BitWidth).lshr(TZ).shl(TZ) + 1);
  else
    ConservativeResult = ConstantRange(
        APInt::getSignedMinValue(BitWidth),
        APInt::getSignedMaxValue(BitWidth).ashr(TZ).shl(TZ) + 1);
}

if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
  ConstantRange X = getRangeRef(Add->getOperand(0), SignHint);
  unsigned WrapType = OBO::AnyWrap;
  if (Add->hasNoSignedWrap())
    WrapType |= OBO::NoSignedWrap;
  if (Add->hasNoUnsignedWrap())
    WrapType |= OBO::NoUnsignedWrap;
  for (unsigned i = 1, e = Add->getNumOperands(); i != e; ++i)
    X = X.addWithNoWrap(getRangeRef(Add->getOperand(i), SignHint),
                        WrapType, RangeType);
  return setRange(Add, SignHint,
                  ConservativeResult.intersectWith(X, RangeType));
}

if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) {
  ConstantRange X = getRangeRef(Mul->getOperand(0), SignHint);
  for (unsigned i = 1, e = Mul->getNumOperands(); i != e; ++i)
    X = X.multiply(getRangeRef(Mul->getOperand(i), SignHint));
  return setRange(Mul, SignHint,
                  ConservativeResult.intersectWith(X, RangeType));
}

if (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(S)) {
  ConstantRange X = getRangeRef(SMax->getOperand(0), SignHint);
  for (unsigned i = 1, e = SMax->getNumOperands(); i != e; ++i)
    X = X.smax(getRangeRef(SMax->getOperand(i), SignHint));
  return setRange(SMax, SignHint,
                  ConservativeResult.intersectWith(X, RangeType));
}

if (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(S)) {
  ConstantRange X = getRangeRef(UMax->getOperand(0), SignHint);
  for (unsigned i = 1, e = UMax->getNumOperands(); i != e; ++i)
    X = X.umax(getRangeRef(UMax->getOperand(i), SignHint));
  return setRange(UMax, SignHint,
                  ConservativeResult.intersectWith(X, RangeType));
}

if (const SCEVSMinExpr *SMin = dyn_cast<SCEVSMinExpr>(S)) {
  ConstantRange X = getRangeRef(SMin->getOperand(0), SignHint);
  for (unsigned i = 1, e = SMin->getNumOperands(); i != e; ++i)
    X = X.smin(getRangeRef(SMin->getOperand(i), SignHint));
  return setRange(SMin, SignHint,
                  ConservativeResult.intersectWith(X, RangeType));
}

if (const SCEVUMinExpr *UMin = dyn_cast<SCEVUMinExpr>(S)) {
  ConstantRange X = getRangeRef(UMin->getOperand(0), SignHint);
  for (unsigned i = 1, e = UMin->getNumOperands(); i != e; ++i)
    X = X.umin(getRangeRef(UMin->getOperand(i), SignHint));
  return setRange(UMin, SignHint,
                  ConservativeResult.intersectWith(X, RangeType));
}

if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) {
  ConstantRange X = getRangeRef(UDiv->getLHS(), SignHint);
  ConstantRange Y = getRangeRef(UDiv->getRHS(), SignHint);
  return setRange(UDiv, SignHint,
                  ConservativeResult.intersectWith(X.udiv(Y), RangeType));
}

if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) {
  ConstantRange X = getRangeRef(ZExt->getOperand(), SignHint);
  return setRange(ZExt, SignHint,
                  ConservativeResult.intersectWith(X.zeroExtend(BitWidth),
                                                   RangeType));
}

if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) {
  ConstantRange X = getRangeRef(SExt->getOperand(), SignHint);
  return setRange(SExt, SignHint,
                  ConservativeResult.intersectWith(X.signExtend(BitWidth),
                                                   RangeType));
}

if (const SCEVPtrToIntExpr *PtrToInt = dyn_cast<SCEVPtrToIntExpr>(S)) {
  ConstantRange X = getRangeRef(PtrToInt->getOperand(), SignHint);
  return setRange(PtrToInt, SignHint, X);
}

if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) {
  ConstantRange X = getRangeRef(Trunc->getOperand(), SignHint);
  return setRange(Trunc, SignHint,
                  ConservativeResult.intersectWith(X.truncate(BitWidth),
                                                   RangeType));
}

if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
  // If there's no unsigned wrap, the value will never be less than its
  // initial value.
  if (AddRec->hasNoUnsignedWrap()) {
    APInt UnsignedMinValue = getUnsignedRangeMin(AddRec->getStart());
    if (!UnsignedMinValue.isNullValue())
      ConservativeResult = ConservativeResult.intersectWith(
          ConstantRange(UnsignedMinValue, APInt(BitWidth, 0)), RangeType);
  }

  // If there's no signed wrap, and all the operands except initial value have
  // the same sign or zero, the value won't ever be:
  // 1: smaller than initial value if operands are non negative,
  // 2: bigger than initial value if operands are non positive.
  // For both cases, value can not cross signed min/max boundary.
  if (AddRec->hasNoSignedWrap()) {
    bool AllNonNeg = true;
    bool AllNonPos = true;
    for (unsigned i = 1, e = AddRec->getNumOperands(); i != e; ++i) {
      if (!isKnownNonNegative(AddRec->getOperand(i)))
        AllNonNeg = false;
      if (!isKnownNonPositive(AddRec->getOperand(i)))
        AllNonPos = false;
    }
    if (AllNonNeg)
      ConservativeResult = ConservativeResult.intersectWith(
          ConstantRange::getNonEmpty(getSignedRangeMin(AddRec->getStart()),
                                     APInt::getSignedMinValue(BitWidth)),
          RangeType);
    else if (AllNonPos)
      ConservativeResult = ConservativeResult.intersectWith(
          ConstantRange::getNonEmpty(
              APInt::getSignedMinValue(BitWidth),
              getSignedRangeMax(AddRec->getStart()) + 1),
          RangeType);
  }

  // TODO: non-affine addrec
  if (AddRec->isAffine()) {
    const SCEV *MaxBECount = getConstantMaxBackedgeTakenCount(AddRec->getLoop());
    if (!isa<SCEVCouldNotCompute>(MaxBECount) &&
        getTypeSizeInBits(MaxBECount->getType()) <= BitWidth) {
      auto RangeFromAffine = getRangeForAffineAR(
          AddRec->getStart(), AddRec->getStepRecurrence(*this), MaxBECount,
          BitWidth);
      ConservativeResult =
          ConservativeResult.intersectWith(RangeFromAffine, RangeType);

      auto RangeFromFactoring = getRangeViaFactoring(
          AddRec->getStart(), AddRec->getStepRecurrence(*this), MaxBECount,
          BitWidth);
      ConservativeResult =
          ConservativeResult.intersectWith(RangeFromFactoring, RangeType);
    }

    // Now try symbolic BE count and more powerful methods.
    if (UseExpensiveRangeSharpening) {
      const SCEV *SymbolicMaxBECount =
          getSymbolicMaxBackedgeTakenCount(AddRec->getLoop());
      if (!isa<SCEVCouldNotCompute>(SymbolicMaxBECount) &&
          getTypeSizeInBits(MaxBECount->getType()) <= BitWidth &&
          AddRec->hasNoSelfWrap()) {
        auto RangeFromAffineNew = getRangeForAffineNoSelfWrappingAR(
            AddRec, SymbolicMaxBECount, BitWidth, SignHint);
        ConservativeResult =
            ConservativeResult.intersectWith(RangeFromAffineNew, RangeType);
      }
    }
  }

  return setRange(AddRec, SignHint, std::move(ConservativeResult));
}

if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
  // Check if the IR explicitly contains !range metadata.
  Optional<ConstantRange> MDRange = GetRangeFromMetadata(U->getValue());
  if (MDRange.hasValue())
    ConservativeResult = ConservativeResult.intersectWith(MDRange.getValue(),
                                                          RangeType);

  // Split here to avoid paying the compile-time cost of calling both
  // computeKnownBits and ComputeNumSignBits.  This restriction can be lifted
  // if needed.
  const DataLayout &DL = getDataLayout();
  if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED) {
    // For a SCEVUnknown, ask ValueTracking.
    KnownBits Known = computeKnownBits(U->getValue(), DL, 0, &AC, nullptr, &DT);
    if (Known.getBitWidth() != BitWidth)
      Known = Known.zextOrTrunc(BitWidth);
    // If Known does not result in full-set, intersect with it.
    if (Known.getMinValue() != Known.getMaxValue() + 1)
      ConservativeResult = ConservativeResult.intersectWith(
          ConstantRange(Known.getMinValue(), Known.getMaxValue() + 1),
          RangeType);
  } else {
    assert(SignHint == ScalarEvolution::HINT_RANGE_SIGNED &&((SignHint == ScalarEvolution::HINT_RANGE_SIGNED && "generalize as needed!"
) ? static_cast<void> (0) : __assert_fail ("SignHint == ScalarEvolution::HINT_RANGE_SIGNED && \"generalize as needed!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5838, __PRETTY_FUNCTION__))
           "generalize as needed!")((SignHint == ScalarEvolution::HINT_RANGE_SIGNED && "generalize as needed!"
) ? static_cast<void> (0) : __assert_fail ("SignHint == ScalarEvolution::HINT_RANGE_SIGNED && \"generalize as needed!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5838, __PRETTY_FUNCTION__));
    unsigned NS = ComputeNumSignBits(U->getValue(), DL, 0, &AC, nullptr, &DT);
    // If the pointer size is larger than the index size type, this can cause
    // NS to be larger than BitWidth. So compensate for this.
    if (U->getType()->isPointerTy()) {
      unsigned ptrSize = DL.getPointerTypeSizeInBits(U->getType());
      int ptrIdxDiff = ptrSize - BitWidth;
      if (ptrIdxDiff > 0 && ptrSize > BitWidth && NS > (unsigned)ptrIdxDiff)
        NS -= ptrIdxDiff;
    }

    if (NS > 1)
      ConservativeResult = ConservativeResult.intersectWith(
          ConstantRange(APInt::getSignedMinValue(BitWidth).ashr(NS - 1),
                        APInt::getSignedMaxValue(BitWidth).ashr(NS - 1) + 1),
          RangeType);
  }

  // A range of Phi is a subset of union of all ranges of its input.
  if (const PHINode *Phi = dyn_cast<PHINode>(U->getValue())) {
    // Make sure that we do not run over cycled Phis.
    if (PendingPhiRanges.insert(Phi).second) {
      ConstantRange RangeFromOps(BitWidth, /*isFullSet=*/false);
      for (auto &Op : Phi->operands()) {
        auto OpRange = getRangeRef(getSCEV(Op), SignHint);
        RangeFromOps = RangeFromOps.unionWith(OpRange);
        // No point to continue if we already have a full set.
        if (RangeFromOps.isFullSet())
          break;
      }
      ConservativeResult =
          ConservativeResult.intersectWith(RangeFromOps, RangeType);
      bool Erased = PendingPhiRanges.erase(Phi);
      assert(Erased && "Failed to erase Phi properly?")((Erased && "Failed to erase Phi properly?") ? static_cast
<void> (0) : __assert_fail ("Erased && \"Failed to erase Phi properly?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5871, __PRETTY_FUNCTION__));
      (void) Erased;
    }
  }

  return setRange(U, SignHint, std::move(ConservativeResult));
}

return setRange(S, SignHint, std::move(ConservativeResult));
5880}

5882// Given a StartRange, Step and MaxBECount for an expression compute a range of
5883// values that the expression can take. Initially, the expression has a value
5884// from StartRange and then is changed by Step up to MaxBECount times. Signed
5885// argument defines if we treat Step as signed or unsigned.
5886static ConstantRange getRangeForAffineARHelper(APInt Step,
                                             const ConstantRange &StartRange,
                                             const APInt &MaxBECount,
                                             unsigned BitWidth, bool Signed) {
// If either Step or MaxBECount is 0, then the expression won't change, and we
// just need to return the initial range.
if (Step == 0 || MaxBECount == 0)
  return StartRange;

// If we don't know anything about the initial value (i.e. StartRange is
// FullRange), then we don't know anything about the final range either.
// Return FullRange.
if (StartRange.isFullSet())
  return ConstantRange::getFull(BitWidth);

// If Step is signed and negative, then we use its absolute value, but we also
// note that we're moving in the opposite direction.
bool Descending = Signed && Step.isNegative();

if (Signed)
  // This is correct even for INT_SMIN. Let's look at i8 to illustrate this:
  // abs(INT_SMIN) = abs(-128) = abs(0x80) = -0x80 = 0x80 = 128.
  // This equations hold true due to the well-defined wrap-around behavior of
  // APInt.
  Step = Step.abs();

// Check if Offset is more than full span of BitWidth. If it is, the
// expression is guaranteed to overflow.
if (APInt::getMaxValue(StartRange.getBitWidth()).udiv(Step).ult(MaxBECount))
  return ConstantRange::getFull(BitWidth);

// Offset is by how much the expression can change. Checks above guarantee no
// overflow here.
APInt Offset = Step * MaxBECount;

// Minimum value of the final range will match the minimal value of StartRange
// if the expression is increasing and will be decreased by Offset otherwise.
// Maximum value of the final range will match the maximal value of StartRange
// if the expression is decreasing and will be increased by Offset otherwise.
APInt StartLower = StartRange.getLower();
APInt StartUpper = StartRange.getUpper() - 1;
APInt MovedBoundary = Descending ? (StartLower - std::move(Offset))
                                 : (StartUpper + std::move(Offset));

// It's possible that the new minimum/maximum value will fall into the initial
// range (due to wrap around). This means that the expression can take any
// value in this bitwidth, and we have to return full range.
if (StartRange.contains(MovedBoundary))
  return ConstantRange::getFull(BitWidth);

APInt NewLower =
    Descending ? std::move(MovedBoundary) : std::move(StartLower);
APInt NewUpper =
    Descending ? std::move(StartUpper) : std::move(MovedBoundary);
NewUpper += 1;

// No overflow detected, return [StartLower, StartUpper + Offset + 1) range.
return ConstantRange::getNonEmpty(std::move(NewLower), std::move(NewUpper));
5944}

5946ConstantRange ScalarEvolution::getRangeForAffineAR(const SCEV *Start,
                                                 const SCEV *Step,
                                                 const SCEV *MaxBECount,
                                                 unsigned BitWidth) {
assert(!isa<SCEVCouldNotCompute>(MaxBECount) &&((!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits
(MaxBECount->getType()) <= BitWidth && "Precondition!"
) ? static_cast<void> (0) : __assert_fail ("!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits(MaxBECount->getType()) <= BitWidth && \"Precondition!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5952, __PRETTY_FUNCTION__))
       getTypeSizeInBits(MaxBECount->getType()) <= BitWidth &&((!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits
(MaxBECount->getType()) <= BitWidth && "Precondition!"
) ? static_cast<void> (0) : __assert_fail ("!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits(MaxBECount->getType()) <= BitWidth && \"Precondition!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5952, __PRETTY_FUNCTION__))
       "Precondition!")((!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits
(MaxBECount->getType()) <= BitWidth && "Precondition!"
) ? static_cast<void> (0) : __assert_fail ("!isa<SCEVCouldNotCompute>(MaxBECount) && getTypeSizeInBits(MaxBECount->getType()) <= BitWidth && \"Precondition!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5952, __PRETTY_FUNCTION__));

MaxBECount = getNoopOrZeroExtend(MaxBECount, Start->getType());
APInt MaxBECountValue = getUnsignedRangeMax(MaxBECount);

// First, consider step signed.
ConstantRange StartSRange = getSignedRange(Start);
ConstantRange StepSRange = getSignedRange(Step);

// If Step can be both positive and negative, we need to find ranges for the
// maximum absolute step values in both directions and union them.
ConstantRange SR =
    getRangeForAffineARHelper(StepSRange.getSignedMin(), StartSRange,
                              MaxBECountValue, BitWidth, /* Signed = */ true);
SR = SR.unionWith(getRangeForAffineARHelper(StepSRange.getSignedMax(),
                                            StartSRange, MaxBECountValue,
                                            BitWidth, /* Signed = */ true));

// Next, consider step unsigned.
ConstantRange UR = getRangeForAffineARHelper(
    getUnsignedRangeMax(Step), getUnsignedRange(Start),
    MaxBECountValue, BitWidth, /* Signed = */ false);

// Finally, intersect signed and unsigned ranges.
return SR.intersectWith(UR, ConstantRange::Smallest);
5977}

5979ConstantRange ScalarEvolution::getRangeForAffineNoSelfWrappingAR(
  const SCEVAddRecExpr *AddRec, const SCEV *MaxBECount, unsigned BitWidth,
  ScalarEvolution::RangeSignHint SignHint) {
assert(AddRec->isAffine() && "Non-affine AddRecs are not suppored!\n")((AddRec->isAffine() && "Non-affine AddRecs are not suppored!\n"
) ? static_cast<void> (0) : __assert_fail ("AddRec->isAffine() && \"Non-affine AddRecs are not suppored!\\n\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5982, __PRETTY_FUNCTION__));
assert(AddRec->hasNoSelfWrap() &&((AddRec->hasNoSelfWrap() && "This only works for non-self-wrapping AddRecs!"
) ? static_cast<void> (0) : __assert_fail ("AddRec->hasNoSelfWrap() && \"This only works for non-self-wrapping AddRecs!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5984, __PRETTY_FUNCTION__))
       "This only works for non-self-wrapping AddRecs!")((AddRec->hasNoSelfWrap() && "This only works for non-self-wrapping AddRecs!"
) ? static_cast<void> (0) : __assert_fail ("AddRec->hasNoSelfWrap() && \"This only works for non-self-wrapping AddRecs!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 5984, __PRETTY_FUNCTION__));
const bool IsSigned = SignHint == HINT_RANGE_SIGNED;
const SCEV *Step = AddRec->getStepRecurrence(*this);
// Only deal with constant step to save compile time.
if (!isa<SCEVConstant>(Step))
  return ConstantRange::getFull(BitWidth);
// Let's make sure that we can prove that we do not self-wrap during
// MaxBECount iterations. We need this because MaxBECount is a maximum
// iteration count estimate, and we might infer nw from some exit for which we
// do not know max exit count (or any other side reasoning).
// TODO: Turn into assert at some point.
MaxBECount = getNoopOrZeroExtend(MaxBECount, AddRec->getType());
const SCEV *RangeWidth = getMinusOne(AddRec->getType());
const SCEV *StepAbs = getUMinExpr(Step, getNegativeSCEV(Step));
const SCEV *MaxItersWithoutWrap = getUDivExpr(RangeWidth, StepAbs);
if (!isKnownPredicateViaConstantRanges(ICmpInst::ICMP_ULE, MaxBECount,
                                       MaxItersWithoutWrap))
  return ConstantRange::getFull(BitWidth);

ICmpInst::Predicate LEPred =
    IsSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
ICmpInst::Predicate GEPred =
    IsSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
const SCEV *End = AddRec->evaluateAtIteration(MaxBECount, *this);

// We know that there is no self-wrap. Let's take Start and End values and
// look at all intermediate values V1, V2, ..., Vn that IndVar takes during
// the iteration. They either lie inside the range [Min(Start, End),
// Max(Start, End)] or outside it:
//
// Case 1:   RangeMin    ...    Start V1 ... VN End ...           RangeMax;
// Case 2:   RangeMin Vk ... V1 Start    ...    End Vn ... Vk + 1 RangeMax;
//
// No self wrap flag guarantees that the intermediate values cannot be BOTH
// outside and inside the range [Min(Start, End), Max(Start, End)]. Using that
// knowledge, let's try to prove that we are dealing with Case 1. It is so if
// Start <= End and step is positive, or Start >= End and step is negative.
const SCEV *Start = AddRec->getStart();
ConstantRange StartRange = getRangeRef(Start, SignHint);
ConstantRange EndRange = getRangeRef(End, SignHint);
ConstantRange RangeBetween = StartRange.unionWith(EndRange);
// If they already cover full iteration space, we will know nothing useful
// even if we prove what we want to prove.
if (RangeBetween.isFullSet())
  return RangeBetween;
// Only deal with ranges that do not wrap (i.e. RangeMin < RangeMax).
bool IsWrappedSet = IsSigned ? RangeBetween.isSignWrappedSet()
                             : RangeBetween.isWrappedSet();
if (IsWrappedSet)
  return ConstantRange::getFull(BitWidth);

if (isKnownPositive(Step) &&
    isKnownPredicateViaConstantRanges(LEPred, Start, End))
  return RangeBetween;
else if (isKnownNegative(Step) &&
         isKnownPredicateViaConstantRanges(GEPred, Start, End))
  return RangeBetween;
return ConstantRange::getFull(BitWidth);
6042}

6044ConstantRange ScalarEvolution::getRangeViaFactoring(const SCEV *Start,
                                                  const SCEV *Step,
                                                  const SCEV *MaxBECount,
                                                  unsigned BitWidth) {
//    RangeOf({C?A:B,+,C?P:Q}) == RangeOf(C?{A,+,P}:{B,+,Q})
// == RangeOf({A,+,P}) union RangeOf({B,+,Q})

struct SelectPattern {
  Value *Condition = nullptr;
  APInt TrueValue;
  APInt FalseValue;

  explicit SelectPattern(ScalarEvolution &SE, unsigned BitWidth,
                         const SCEV *S) {
    Optional<unsigned> CastOp;
    APInt Offset(BitWidth, 0);

    assert(SE.getTypeSizeInBits(S->getType()) == BitWidth &&((SE.getTypeSizeInBits(S->getType()) == BitWidth &&
 "Should be!") ? static_cast<void> (0) : __assert_fail (
"SE.getTypeSizeInBits(S->getType()) == BitWidth && \"Should be!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6062, __PRETTY_FUNCTION__))
           "Should be!")((SE.getTypeSizeInBits(S->getType()) == BitWidth &&
 "Should be!") ? static_cast<void> (0) : __assert_fail (
"SE.getTypeSizeInBits(S->getType()) == BitWidth && \"Should be!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6062, __PRETTY_FUNCTION__));

    // Peel off a constant offset:
    if (auto *SA = dyn_cast<SCEVAddExpr>(S)) {
      // In the future we could consider being smarter here and handle
      // {Start+Step,+,Step} too.
      if (SA->getNumOperands() != 2 || !isa<SCEVConstant>(SA->getOperand(0)))
        return;

      Offset = cast<SCEVConstant>(SA->getOperand(0))->getAPInt();
      S = SA->getOperand(1);
    }

    // Peel off a cast operation
    if (auto *SCast = dyn_cast<SCEVIntegralCastExpr>(S)) {
      CastOp = SCast->getSCEVType();
      S = SCast->getOperand();
    }

    using namespace llvm::PatternMatch;

    auto *SU = dyn_cast<SCEVUnknown>(S);
    const APInt *TrueVal, *FalseVal;
    if (!SU ||
        !match(SU->getValue(), m_Select(m_Value(Condition), m_APInt(TrueVal),
                                        m_APInt(FalseVal)))) {
      Condition = nullptr;
      return;
    }

    TrueValue = *TrueVal;
    FalseValue = *FalseVal;

    // Re-apply the cast we peeled off earlier
    if (CastOp.hasValue())
      switch (*CastOp) {
      default:
        llvm_unreachable("Unknown SCEV cast type!")::llvm::llvm_unreachable_internal("Unknown SCEV cast type!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6099);

      case scTruncate:
        TrueValue = TrueValue.trunc(BitWidth);
        FalseValue = FalseValue.trunc(BitWidth);
        break;
      case scZeroExtend:
        TrueValue = TrueValue.zext(BitWidth);
        FalseValue = FalseValue.zext(BitWidth);
        break;
      case scSignExtend:
        TrueValue = TrueValue.sext(BitWidth);
        FalseValue = FalseValue.sext(BitWidth);
        break;
      }

    // Re-apply the constant offset we peeled off earlier
    TrueValue += Offset;
    FalseValue += Offset;
  }

  bool isRecognized() { return Condition != nullptr; }
};

SelectPattern StartPattern(*this, BitWidth, Start);
if (!StartPattern.isRecognized())
  return ConstantRange::getFull(BitWidth);

SelectPattern StepPattern(*this, BitWidth, Step);
if (!StepPattern.isRecognized())
  return ConstantRange::getFull(BitWidth);

if (StartPattern.Condition != StepPattern.Condition) {
  // We don't handle this case today; but we could, by considering four
  // possibilities below instead of two. I'm not sure if there are cases where
  // that will help over what getRange already does, though.
  return ConstantRange::getFull(BitWidth);
}

// NB! Calling ScalarEvolution::getConstant is fine, but we should not try to
// construct arbitrary general SCEV expressions here.  This function is called
// from deep in the call stack, and calling getSCEV (on a sext instruction,
// say) can end up caching a suboptimal value.

// FIXME: without the explicit `this` receiver below, MSVC errors out with
// C2352 and C2512 (otherwise it isn't needed).

const SCEV *TrueStart = this->getConstant(StartPattern.TrueValue);
const SCEV *TrueStep = this->getConstant(StepPattern.TrueValue);
const SCEV *FalseStart = this->getConstant(StartPattern.FalseValue);
const SCEV *FalseStep = this->getConstant(StepPattern.FalseValue);

ConstantRange TrueRange =
    this->getRangeForAffineAR(TrueStart, TrueStep, MaxBECount, BitWidth);
ConstantRange FalseRange =
    this->getRangeForAffineAR(FalseStart, FalseStep, MaxBECount, BitWidth);

return TrueRange.unionWith(FalseRange);
6157}

6159SCEV::NoWrapFlags ScalarEvolution::getNoWrapFlagsFromUB(const Value *V) {
if (isa<ConstantExpr>(V)) return SCEV::FlagAnyWrap;
const BinaryOperator *BinOp = cast<BinaryOperator>(V);

// Return early if there are no flags to propagate to the SCEV.
SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap;
if (BinOp->hasNoUnsignedWrap())
  Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW);
if (BinOp->hasNoSignedWrap())
  Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNSW);
if (Flags == SCEV::FlagAnyWrap)
  return SCEV::FlagAnyWrap;

return isSCEVExprNeverPoison(BinOp) ? Flags : SCEV::FlagAnyWrap;
6173}

6175bool ScalarEvolution::isSCEVExprNeverPoison(const Instruction *I) {
// Here we check that I is in the header of the innermost loop containing I,
// since we only deal with instructions in the loop header. The actual loop we
// need to check later will come from an add recurrence, but getting that
// requires computing the SCEV of the operands, which can be expensive. This
// check we can do cheaply to rule out some cases early.
Loop *InnermostContainingLoop = LI.getLoopFor(I->getParent());
if (InnermostContainingLoop == nullptr ||
    InnermostContainingLoop->getHeader() != I->getParent())
  return false;

// Only proceed if we can prove that I does not yield poison.
if (!programUndefinedIfPoison(I))
  return false;

// At this point we know that if I is executed, then it does not wrap
// according to at least one of NSW or NUW. If I is not executed, then we do
// not know if the calculation that I represents would wrap. Multiple
// instructions can map to the same SCEV. If we apply NSW or NUW from I to
// the SCEV, we must guarantee no wrapping for that SCEV also when it is
// derived from other instructions that map to the same SCEV. We cannot make
// that guarantee for cases where I is not executed. So we need to find the
// loop that I is considered in relation to and prove that I is executed for
// every iteration of that loop. That implies that the value that I
// calculates does not wrap anywhere in the loop, so then we can apply the
// flags to the SCEV.
//
// We check isLoopInvariant to disambiguate in case we are adding recurrences
// from different loops, so that we know which loop to prove that I is
// executed in.
for (unsigned OpIndex = 0; OpIndex < I->getNumOperands(); ++OpIndex) {
  // I could be an extractvalue from a call to an overflow intrinsic.
  // TODO: We can do better here in some cases.
  if (!isSCEVable(I->getOperand(OpIndex)->getType()))
    return false;
  const SCEV *Op = getSCEV(I->getOperand(OpIndex));
  if (auto *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) {
    bool AllOtherOpsLoopInvariant = true;
    for (unsigned OtherOpIndex = 0; OtherOpIndex < I->getNumOperands();
         ++OtherOpIndex) {
      if (OtherOpIndex != OpIndex) {
        const SCEV *OtherOp = getSCEV(I->getOperand(OtherOpIndex));
        if (!isLoopInvariant(OtherOp, AddRec->getLoop())) {
          AllOtherOpsLoopInvariant = false;
          break;
        }
      }
    }
    if (AllOtherOpsLoopInvariant &&
        isGuaranteedToExecuteForEveryIteration(I, AddRec->getLoop()))
      return true;
  }
}
return false;
6229}

6231bool ScalarEvolution::isAddRecNeverPoison(const Instruction *I, const Loop *L) {
// If we know that \c I can never be poison period, then that's enough.
if (isSCEVExprNeverPoison(I))
  return true;

// For an add recurrence specifically, we assume that infinite loops without
// side effects are undefined behavior, and then reason as follows:
//
// If the add recurrence is poison in any iteration, it is poison on all
// future iterations (since incrementing poison yields poison). If the result
// of the add recurrence is fed into the loop latch condition and the loop
// does not contain any throws or exiting blocks other than the latch, we now
// have the ability to "choose" whether the backedge is taken or not (by
// choosing a sufficiently evil value for the poison feeding into the branch)
// for every iteration including and after the one in which \p I first became
// poison.  There are two possibilities (let's call the iteration in which \p
// I first became poison as K):
//
//  1. In the set of iterations including and after K, the loop body executes
//     no side effects.  In this case executing the backege an infinte number
//     of times will yield undefined behavior.
//
//  2. In the set of iterations including and after K, the loop body executes
//     at least one side effect.  In this case, that specific instance of side
//     effect is control dependent on poison, which also yields undefined
//     behavior.

auto *ExitingBB = L->getExitingBlock();
auto *LatchBB = L->getLoopLatch();
if (!ExitingBB || !LatchBB || ExitingBB != LatchBB)
  return false;

SmallPtrSet<const Instruction *, 16> Pushed;
SmallVector<const Instruction *, 8> PoisonStack;

// We start by assuming \c I, the post-inc add recurrence, is poison.  Only
// things that are known to be poison under that assumption go on the
// PoisonStack.
Pushed.insert(I);
PoisonStack.push_back(I);

bool LatchControlDependentOnPoison = false;
while (!PoisonStack.empty() && !LatchControlDependentOnPoison) {
  const Instruction *Poison = PoisonStack.pop_back_val();

  for (auto *PoisonUser : Poison->users()) {
    if (propagatesPoison(cast<Operator>(PoisonUser))) {
      if (Pushed.insert(cast<Instruction>(PoisonUser)).second)
        PoisonStack.push_back(cast<Instruction>(PoisonUser));
    } else if (auto *BI = dyn_cast<BranchInst>(PoisonUser)) {
      assert(BI->isConditional() && "Only possibility!")((BI->isConditional() && "Only possibility!") ? static_cast
<void> (0) : __assert_fail ("BI->isConditional() && \"Only possibility!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6281, __PRETTY_FUNCTION__));
      if (BI->getParent() == LatchBB) {
        LatchControlDependentOnPoison = true;
        break;
      }
    }
  }
}

return LatchControlDependentOnPoison && loopHasNoAbnormalExits(L);
6291}

6293ScalarEvolution::LoopProperties
6294ScalarEvolution::getLoopProperties(const Loop *L) {
using LoopProperties = ScalarEvolution::LoopProperties;

auto Itr = LoopPropertiesCache.find(L);
if (Itr == LoopPropertiesCache.end()) {
  auto HasSideEffects = [](Instruction *I) {
    if (auto *SI = dyn_cast<StoreInst>(I))
      return !SI->isSimple();

    return I->mayHaveSideEffects();
  };

  LoopProperties LP = {/* HasNoAbnormalExits */ true,
                       /*HasNoSideEffects*/ true};

  for (auto *BB : L->getBlocks())
    for (auto &I : *BB) {
      if (!isGuaranteedToTransferExecutionToSuccessor(&I))
        LP.HasNoAbnormalExits = false;
      if (HasSideEffects(&I))
        LP.HasNoSideEffects = false;
      if (!LP.HasNoAbnormalExits && !LP.HasNoSideEffects)
        break; // We're already as pessimistic as we can get.
    }

  auto InsertPair = LoopPropertiesCache.insert({L, LP});
  assert(InsertPair.second && "We just checked!")((InsertPair.second && "We just checked!") ? static_cast
<void> (0) : __assert_fail ("InsertPair.second && \"We just checked!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6320, __PRETTY_FUNCTION__));
  Itr = InsertPair.first;
}

return Itr->second;
6325}

6327const SCEV *ScalarEvolution::createSCEV(Value *V) {
if (!isSCEVable(V->getType()))
  return getUnknown(V);

if (Instruction *I = dyn_cast<Instruction>(V)) {
  // Don't attempt to analyze instructions in blocks that aren't
  // reachable. Such instructions don't matter, and they aren't required
  // to obey basic rules for definitions dominating uses which this
  // analysis depends on.
  if (!DT.isReachableFromEntry(I->getParent()))
    return getUnknown(UndefValue::get(V->getType()));
} else if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
  return getConstant(CI);
else if (isa<ConstantPointerNull>(V))
  // FIXME: we shouldn't special-case null pointer constant.
  return getZero(V->getType());
else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
  return GA->isInterposable() ? getUnknown(V) : getSCEV(GA->getAliasee());
else if (!isa<ConstantExpr>(V))
  return getUnknown(V);

Operator *U = cast<Operator>(V);
if (auto BO = MatchBinaryOp(U, DT)) {
  switch (BO->Opcode) {
  case Instruction::Add: {
    // The simple thing to do would be to just call getSCEV on both operands
    // and call getAddExpr with the result. However if we're looking at a
    // bunch of things all added together, this can be quite inefficient,
    // because it leads to N-1 getAddExpr calls for N ultimate operands.
    // Instead, gather up all the operands and make a single getAddExpr call.
    // LLVM IR canonical form means we need only traverse the left operands.
    SmallVector<const SCEV *, 4> AddOps;
    do {
      if (BO->Op) {
        if (auto *OpSCEV = getExistingSCEV(BO->Op)) {
          AddOps.push_back(OpSCEV);
          break;
        }

        // If a NUW or NSW flag can be applied to the SCEV for this
        // addition, then compute the SCEV for this addition by itself
        // with a separate call to getAddExpr. We need to do that
        // instead of pushing the operands of the addition onto AddOps,
        // since the flags are only known to apply to this particular
        // addition - they may not apply to other additions that can be
        // formed with operands from AddOps.
        const SCEV *RHS = getSCEV(BO->RHS);
        SCEV::NoWrapFlags Flags = getNoWrapFlagsFromUB(BO->Op);
        if (Flags != SCEV::FlagAnyWrap) {
          const SCEV *LHS = getSCEV(BO->LHS);
          if (BO->Opcode == Instruction::Sub)
            AddOps.push_back(getMinusSCEV(LHS, RHS, Flags));
          else
            AddOps.push_back(getAddExpr(LHS, RHS, Flags));
          break;
        }
      }

      if (BO->Opcode == Instruction::Sub)
        AddOps.push_back(getNegativeSCEV(getSCEV(BO->RHS)));
      else
        AddOps.push_back(getSCEV(BO->RHS));

      auto NewBO = MatchBinaryOp(BO->LHS, DT);
      if (!NewBO || (NewBO->Opcode != Instruction::Add &&
                     NewBO->Opcode != Instruction::Sub)) {
        AddOps.push_back(getSCEV(BO->LHS));
        break;
      }
      BO = NewBO;
    } while (true);

    return getAddExpr(AddOps);
  }

  case Instruction::Mul: {
    SmallVector<const SCEV *, 4> MulOps;
    do {
      if (BO->Op) {
        if (auto *OpSCEV = getExistingSCEV(BO->Op)) {
          MulOps.push_back(OpSCEV);
          break;
        }

        SCEV::NoWrapFlags Flags = getNoWrapFlagsFromUB(BO->Op);
        if (Flags != SCEV::FlagAnyWrap) {
          MulOps.push_back(
              getMulExpr(getSCEV(BO->LHS), getSCEV(BO->RHS), Flags));
          break;
        }
      }

      MulOps.push_back(getSCEV(BO->RHS));
      auto NewBO = MatchBinaryOp(BO->LHS, DT);
      if (!NewBO || NewBO->Opcode != Instruction::Mul) {
        MulOps.push_back(getSCEV(BO->LHS));
        break;
      }
      BO = NewBO;
    } while (true);

    return getMulExpr(MulOps);
  }
  case Instruction::UDiv:
    return getUDivExpr(getSCEV(BO->LHS), getSCEV(BO->RHS));
  case Instruction::URem:
    return getURemExpr(getSCEV(BO->LHS), getSCEV(BO->RHS));
  case Instruction::Sub: {
    SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap;
    if (BO->Op)
      Flags = getNoWrapFlagsFromUB(BO->Op);
    return getMinusSCEV(getSCEV(BO->LHS), getSCEV(BO->RHS), Flags);
  }
  case Instruction::And:
    // For an expression like x&255 that merely masks off the high bits,
    // use zext(trunc(x)) as the SCEV expression.
    if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS)) {
      if (CI->isZero())
        return getSCEV(BO->RHS);
      if (CI->isMinusOne())
        return getSCEV(BO->LHS);
      const APInt &A = CI->getValue();

      // Instcombine's ShrinkDemandedConstant may strip bits out of
      // constants, obscuring what would otherwise be a low-bits mask.
      // Use computeKnownBits to compute what ShrinkDemandedConstant
      // knew about to reconstruct a low-bits mask value.
      unsigned LZ = A.countLeadingZeros();
      unsigned TZ = A.countTrailingZeros();
      unsigned BitWidth = A.getBitWidth();
      KnownBits Known(BitWidth);
      computeKnownBits(BO->LHS, Known, getDataLayout(),
                       0, &AC, nullptr, &DT);

      APInt EffectiveMask =
          APInt::getLowBitsSet(BitWidth, BitWidth - LZ - TZ).shl(TZ);
      if ((LZ != 0 || TZ != 0) && !((~A & ~Known.Zero) & EffectiveMask)) {
        const SCEV *MulCount = getConstant(APInt::getOneBitSet(BitWidth, TZ));
        const SCEV *LHS = getSCEV(BO->LHS);
        const SCEV *ShiftedLHS = nullptr;
        if (auto *LHSMul = dyn_cast<SCEVMulExpr>(LHS)) {
          if (auto *OpC = dyn_cast<SCEVConstant>(LHSMul->getOperand(0))) {
            // For an expression like (x * 8) & 8, simplify the multiply.
            unsigned MulZeros = OpC->getAPInt().countTrailingZeros();
            unsigned GCD = std::min(MulZeros, TZ);
            APInt DivAmt = APInt::getOneBitSet(BitWidth, TZ - GCD);
            SmallVector<const SCEV*, 4> MulOps;
            MulOps.push_back(getConstant(OpC->getAPInt().lshr(GCD)));
            MulOps.append(LHSMul->op_begin() + 1, LHSMul->op_end());
            auto *NewMul = getMulExpr(MulOps, LHSMul->getNoWrapFlags());
            ShiftedLHS = getUDivExpr(NewMul, getConstant(DivAmt));
          }
        }
        if (!ShiftedLHS)
          ShiftedLHS = getUDivExpr(LHS, MulCount);
        return getMulExpr(
            getZeroExtendExpr(
                getTruncateExpr(ShiftedLHS,
                    IntegerType::get(getContext(), BitWidth - LZ - TZ)),
                BO->LHS->getType()),
            MulCount);
      }
    }
    break;

  case Instruction::Or:
    // If the RHS of the Or is a constant, we may have something like:
    // X*4+1 which got turned into X*4|1.  Handle this as an Add so loop
    // optimizations will transparently handle this case.
    //
    // In order for this transformation to be safe, the LHS must be of the
    // form X*(2^n) and the Or constant must be less than 2^n.
    if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS)) {
      const SCEV *LHS = getSCEV(BO->LHS);
      const APInt &CIVal = CI->getValue();
      if (GetMinTrailingZeros(LHS) >=
          (CIVal.getBitWidth() - CIVal.countLeadingZeros())) {
        // Build a plain add SCEV.
        return getAddExpr(LHS, getSCEV(CI),
                          (SCEV::NoWrapFlags)(SCEV::FlagNUW | SCEV::FlagNSW));
      }
    }
    break;

  case Instruction::Xor:
    if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS)) {
      // If the RHS of xor is -1, then this is a not operation.
      if (CI->isMinusOne())
        return getNotSCEV(getSCEV(BO->LHS));

      // Model xor(and(x, C), C) as and(~x, C), if C is a low-bits mask.
      // This is a variant of the check for xor with -1, and it handles
      // the case where instcombine has trimmed non-demanded bits out
      // of an xor with -1.
      if (auto *LBO = dyn_cast<BinaryOperator>(BO->LHS))
        if (ConstantInt *LCI = dyn_cast<ConstantInt>(LBO->getOperand(1)))
          if (LBO->getOpcode() == Instruction::And &&
              LCI->getValue() == CI->getValue())
            if (const SCEVZeroExtendExpr *Z =
                    dyn_cast<SCEVZeroExtendExpr>(getSCEV(BO->LHS))) {
              Type *UTy = BO->LHS->getType();
              const SCEV *Z0 = Z->getOperand();
              Type *Z0Ty = Z0->getType();
              unsigned Z0TySize = getTypeSizeInBits(Z0Ty);

              // If C is a low-bits mask, the zero extend is serving to
              // mask off the high bits. Complement the operand and
              // re-apply the zext.
              if (CI->getValue().isMask(Z0TySize))
                return getZeroExtendExpr(getNotSCEV(Z0), UTy);

              // If C is a single bit, it may be in the sign-bit position
              // before the zero-extend. In this case, represent the xor
              // using an add, which is equivalent, and re-apply the zext.
              APInt Trunc = CI->getValue().trunc(Z0TySize);
              if (Trunc.zext(getTypeSizeInBits(UTy)) == CI->getValue() &&
                  Trunc.isSignMask())
                return getZeroExtendExpr(getAddExpr(Z0, getConstant(Trunc)),
                                         UTy);
            }
    }
    break;

  case Instruction::Shl:
    // Turn shift left of a constant amount into a multiply.
    if (ConstantInt *SA = dyn_cast<ConstantInt>(BO->RHS)) {
      uint32_t BitWidth = cast<IntegerType>(SA->getType())->getBitWidth();

      // If the shift count is not less than the bitwidth, the result of
      // the shift is undefined. Don't try to analyze it, because the
      // resolution chosen here may differ from the resolution chosen in
      // other parts of the compiler.
      if (SA->getValue().uge(BitWidth))
        break;

      // We can safely preserve the nuw flag in all cases. It's also safe to
      // turn a nuw nsw shl into a nuw nsw mul. However, nsw in isolation
      // requires special handling. It can be preserved as long as we're not
      // left shifting by bitwidth - 1.
      auto Flags = SCEV::FlagAnyWrap;
      if (BO->Op) {
        auto MulFlags = getNoWrapFlagsFromUB(BO->Op);
        if ((MulFlags & SCEV::FlagNSW) &&
            ((MulFlags & SCEV::FlagNUW) || SA->getValue().ult(BitWidth - 1)))
          Flags = (SCEV::NoWrapFlags)(Flags | SCEV::FlagNSW);
        if (MulFlags & SCEV::FlagNUW)
          Flags = (SCEV::NoWrapFlags)(Flags | SCEV::FlagNUW);
      }

      Constant *X = ConstantInt::get(
          getContext(), APInt::getOneBitSet(BitWidth, SA->getZExtValue()));
      return getMulExpr(getSCEV(BO->LHS), getSCEV(X), Flags);
    }
    break;

  case Instruction::AShr: {
    // AShr X, C, where C is a constant.
    ConstantInt *CI = dyn_cast<ConstantInt>(BO->RHS);
    if (!CI)
      break;

    Type *OuterTy = BO->LHS->getType();
    uint64_t BitWidth = getTypeSizeInBits(OuterTy);
    // If the shift count is not less than the bitwidth, the result of
    // the shift is undefined. Don't try to analyze it, because the
    // resolution chosen here may differ from the resolution chosen in
    // other parts of the compiler.
    if (CI->getValue().uge(BitWidth))
      break;

    if (CI->isZero())
      return getSCEV(BO->LHS); // shift by zero --> noop

    uint64_t AShrAmt = CI->getZExtValue();
    Type *TruncTy = IntegerType::get(getContext(), BitWidth - AShrAmt);

    Operator *L = dyn_cast<Operator>(BO->LHS);
    if (L && L->getOpcode() == Instruction::Shl) {
      // X = Shl A, n
      // Y = AShr X, m
      // Both n and m are constant.

      const SCEV *ShlOp0SCEV = getSCEV(L->getOperand(0));
      if (L->getOperand(1) == BO->RHS)
        // For a two-shift sext-inreg, i.e. n = m,
        // use sext(trunc(x)) as the SCEV expression.
        return getSignExtendExpr(
            getTruncateExpr(ShlOp0SCEV, TruncTy), OuterTy);

      ConstantInt *ShlAmtCI = dyn_cast<ConstantInt>(L->getOperand(1));
      if (ShlAmtCI && ShlAmtCI->getValue().ult(BitWidth)) {
        uint64_t ShlAmt = ShlAmtCI->getZExtValue();
        if (ShlAmt > AShrAmt) {
          // When n > m, use sext(mul(trunc(x), 2^(n-m)))) as the SCEV
          // expression. We already checked that ShlAmt < BitWidth, so
          // the multiplier, 1 << (ShlAmt - AShrAmt), fits into TruncTy as
          // ShlAmt - AShrAmt < Amt.
          APInt Mul = APInt::getOneBitSet(BitWidth - AShrAmt,
                                          ShlAmt - AShrAmt);
          return getSignExtendExpr(
              getMulExpr(getTruncateExpr(ShlOp0SCEV, TruncTy),
              getConstant(Mul)), OuterTy);
        }
      }
    }
    if (BO->IsExact) {
      // Given exact arithmetic in-bounds right-shift by a constant,
      // we can lower it into:  (abs(x) EXACT/u (1<<C)) * signum(x)
      const SCEV *X = getSCEV(BO->LHS);
      const SCEV *AbsX = getAbsExpr(X, /*IsNSW=*/false);
      APInt Mult = APInt::getOneBitSet(BitWidth, AShrAmt);
      const SCEV *Div = getUDivExactExpr(AbsX, getConstant(Mult));
      return getMulExpr(Div, getSignumExpr(X), SCEV::FlagNSW);
    }
    break;
  }
  }
}

switch (U->getOpcode()) {
case Instruction::Trunc:
  return getTruncateExpr(getSCEV(U->getOperand(0)), U->getType());

case Instruction::ZExt:
  return getZeroExtendExpr(getSCEV(U->getOperand(0)), U->getType());

case Instruction::SExt:
  if (auto BO = MatchBinaryOp(U->getOperand(0), DT)) {
    // The NSW flag of a subtract does not always survive the conversion to
    // A + (-1)*B.  By pushing sign extension onto its operands we are much
    // more likely to preserve NSW and allow later AddRec optimisations.
    //
    // NOTE: This is effectively duplicating this logic from getSignExtend:
    //   sext((A + B + ...)<nsw>) --> (sext(A) + sext(B) + ...)<nsw>
    // but by that point the NSW information has potentially been lost.
    if (BO->Opcode == Instruction::Sub && BO->IsNSW) {
      Type *Ty = U->getType();
      auto *V1 = getSignExtendExpr(getSCEV(BO->LHS), Ty);
      auto *V2 = getSignExtendExpr(getSCEV(BO->RHS), Ty);
      return getMinusSCEV(V1, V2, SCEV::FlagNSW);
    }
  }
  return getSignExtendExpr(getSCEV(U->getOperand(0)), U->getType());

case Instruction::BitCast:
  // BitCasts are no-op casts so we just eliminate the cast.
  if (isSCEVable(U->getType()) && isSCEVable(U->getOperand(0)->getType()))
    return getSCEV(U->getOperand(0));
  break;

case Instruction::PtrToInt: {
  // Pointer to integer cast is straight-forward, so do model it.
  Value *Ptr = U->getOperand(0);
  const SCEV *Op = getSCEV(Ptr);
  Type *DstIntTy = U->getType();
  // SCEV doesn't have constant pointer expression type, but it supports
  // nullptr constant (and only that one), which is modelled in SCEV as a
  // zero integer constant. So just skip the ptrtoint cast for constants.
  if (isa<SCEVConstant>(Op))
    return getTruncateOrZeroExtend(Op, DstIntTy);
  Type *PtrTy = Ptr->getType();
  Type *IntPtrTy = getDataLayout().getIntPtrType(PtrTy);
  // But only if effective SCEV (integer) type is wide enough to represent
  // all possible pointer values.
  if (getDataLayout().getTypeSizeInBits(getEffectiveSCEVType(PtrTy)) !=
      getDataLayout().getTypeSizeInBits(IntPtrTy))
    return getUnknown(V);
  return getPtrToIntExpr(Op, DstIntTy);
}
case Instruction::IntToPtr:
  // Just don't deal with inttoptr casts.
  return getUnknown(V);

case Instruction::SDiv:
  // If both operands are non-negative, this is just an udiv.
  if (isKnownNonNegative(getSCEV(U->getOperand(0))) &&
      isKnownNonNegative(getSCEV(U->getOperand(1))))
    return getUDivExpr(getSCEV(U->getOperand(0)), getSCEV(U->getOperand(1)));
  break;

case Instruction::SRem:
  // If both operands are non-negative, this is just an urem.
  if (isKnownNonNegative(getSCEV(U->getOperand(0))) &&
      isKnownNonNegative(getSCEV(U->getOperand(1))))
    return getURemExpr(getSCEV(U->getOperand(0)), getSCEV(U->getOperand(1)));
  break;

case Instruction::GetElementPtr:
  return createNodeForGEP(cast<GEPOperator>(U));

case Instruction::PHI:
  return createNodeForPHI(cast<PHINode>(U));

case Instruction::Select:
  // U can also be a select constant expr, which let fall through.  Since
  // createNodeForSelect only works for a condition that is an `ICmpInst`, and
  // constant expressions cannot have instructions as operands, we'd have
  // returned getUnknown for a select constant expressions anyway.
  if (isa<Instruction>(U))
    return createNodeForSelectOrPHI(cast<Instruction>(U), U->getOperand(0),
                                    U->getOperand(1), U->getOperand(2));
  break;

case Instruction::Call:
case Instruction::Invoke:
  if (Value *RV = cast<CallBase>(U)->getReturnedArgOperand())
    return getSCEV(RV);

  if (auto *II = dyn_cast<IntrinsicInst>(U)) {
    switch (II->getIntrinsicID()) {
    case Intrinsic::abs:
      return getAbsExpr(
          getSCEV(II->getArgOperand(0)),
          /*IsNSW=*/cast<ConstantInt>(II->getArgOperand(1))->isOne());
    case Intrinsic::umax:
      return getUMaxExpr(getSCEV(II->getArgOperand(0)),
                         getSCEV(II->getArgOperand(1)));
    case Intrinsic::umin:
      return getUMinExpr(getSCEV(II->getArgOperand(0)),
                         getSCEV(II->getArgOperand(1)));
    case Intrinsic::smax:
      return getSMaxExpr(getSCEV(II->getArgOperand(0)),
                         getSCEV(II->getArgOperand(1)));
    case Intrinsic::smin:
      return getSMinExpr(getSCEV(II->getArgOperand(0)),
                         getSCEV(II->getArgOperand(1)));
    case Intrinsic::usub_sat: {
      const SCEV *X = getSCEV(II->getArgOperand(0));
      const SCEV *Y = getSCEV(II->getArgOperand(1));
      const SCEV *ClampedY = getUMinExpr(X, Y);
      return getMinusSCEV(X, ClampedY, SCEV::FlagNUW);
    }
    case Intrinsic::uadd_sat: {
      const SCEV *X = getSCEV(II->getArgOperand(0));
      const SCEV *Y = getSCEV(II->getArgOperand(1));
      const SCEV *ClampedX = getUMinExpr(X, getNotSCEV(Y));
      return getAddExpr(ClampedX, Y, SCEV::FlagNUW);
    }
    case Intrinsic::start_loop_iterations:
      // A start_loop_iterations is just equivalent to the first operand for
      // SCEV purposes.
      return getSCEV(II->getArgOperand(0));
    default:
      break;
    }
  }
  break;
}

return getUnknown(V);
6777}

6779//===----------------------------------------------------------------------===//
6780//                   Iteration Count Computation Code
6781//

6783static unsigned getConstantTripCount(const SCEVConstant *ExitCount) {
if (!ExitCount)
  return 0;

ConstantInt *ExitConst = ExitCount->getValue();

// Guard against huge trip counts.
if (ExitConst->getValue().getActiveBits() > 32)
  return 0;

// In case of integer overflow, this returns 0, which is correct.
return ((unsigned)ExitConst->getZExtValue()) + 1;
6795}

6797unsigned ScalarEvolution::getSmallConstantTripCount(const Loop *L) {
if (BasicBlock *ExitingBB = L->getExitingBlock())
  return getSmallConstantTripCount(L, ExitingBB);

// No trip count information for multiple exits.
return 0;
6803}

6805unsigned
6806ScalarEvolution::getSmallConstantTripCount(const Loop *L,
                                         const BasicBlock *ExitingBlock) {
assert(ExitingBlock && "Must pass a non-null exiting block!")((ExitingBlock && "Must pass a non-null exiting block!"
) ? static_cast<void> (0) : __assert_fail ("ExitingBlock && \"Must pass a non-null exiting block!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6808, __PRETTY_FUNCTION__));
assert(L->isLoopExiting(ExitingBlock) &&((L->isLoopExiting(ExitingBlock) && "Exiting block must actually branch out of the loop!"
) ? static_cast<void> (0) : __assert_fail ("L->isLoopExiting(ExitingBlock) && \"Exiting block must actually branch out of the loop!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6810, __PRETTY_FUNCTION__))
       "Exiting block must actually branch out of the loop!")((L->isLoopExiting(ExitingBlock) && "Exiting block must actually branch out of the loop!"
) ? static_cast<void> (0) : __assert_fail ("L->isLoopExiting(ExitingBlock) && \"Exiting block must actually branch out of the loop!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6810, __PRETTY_FUNCTION__));
const SCEVConstant *ExitCount =
    dyn_cast<SCEVConstant>(getExitCount(L, ExitingBlock));
return getConstantTripCount(ExitCount);
6814}

6816unsigned ScalarEvolution::getSmallConstantMaxTripCount(const Loop *L) {
const auto *MaxExitCount =
    dyn_cast<SCEVConstant>(getConstantMaxBackedgeTakenCount(L));
return getConstantTripCount(MaxExitCount);
6820}

6822unsigned ScalarEvolution::getSmallConstantTripMultiple(const Loop *L) {
if (BasicBlock *ExitingBB = L->getExitingBlock())
  return getSmallConstantTripMultiple(L, ExitingBB);

// No trip multiple information for multiple exits.
return 0;
6828}

6830/// Returns the largest constant divisor of the trip count of this loop as a
6831/// normal unsigned value, if possible. This means that the actual trip count is
6832/// always a multiple of the returned value (don't forget the trip count could
6833/// very well be zero as well!).
6834///
6835/// Returns 1 if the trip count is unknown or not guaranteed to be the
6836/// multiple of a constant (which is also the case if the trip count is simply
6837/// constant, use getSmallConstantTripCount for that case), Will also return 1
6838/// if the trip count is very large (>= 2^32).
6839///
6840/// As explained in the comments for getSmallConstantTripCount, this assumes
6841/// that control exits the loop via ExitingBlock.
6842unsigned
6843ScalarEvolution::getSmallConstantTripMultiple(const Loop *L,
                                            const BasicBlock *ExitingBlock) {
assert(ExitingBlock && "Must pass a non-null exiting block!")((ExitingBlock && "Must pass a non-null exiting block!"
) ? static_cast<void> (0) : __assert_fail ("ExitingBlock && \"Must pass a non-null exiting block!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6845, __PRETTY_FUNCTION__));
assert(L->isLoopExiting(ExitingBlock) &&((L->isLoopExiting(ExitingBlock) && "Exiting block must actually branch out of the loop!"
) ? static_cast<void> (0) : __assert_fail ("L->isLoopExiting(ExitingBlock) && \"Exiting block must actually branch out of the loop!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6847, __PRETTY_FUNCTION__))
       "Exiting block must actually branch out of the loop!")((L->isLoopExiting(ExitingBlock) && "Exiting block must actually branch out of the loop!"
) ? static_cast<void> (0) : __assert_fail ("L->isLoopExiting(ExitingBlock) && \"Exiting block must actually branch out of the loop!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6847, __PRETTY_FUNCTION__));
const SCEV *ExitCount = getExitCount(L, ExitingBlock);
if (ExitCount == getCouldNotCompute())
  return 1;

// Get the trip count from the BE count by adding 1.
const SCEV *TCExpr = getAddExpr(ExitCount, getOne(ExitCount->getType()));

const SCEVConstant *TC = dyn_cast<SCEVConstant>(TCExpr);
if (!TC)
  // Attempt to factor more general cases. Returns the greatest power of
  // two divisor. If overflow happens, the trip count expression is still
  // divisible by the greatest power of 2 divisor returned.
  return 1U << std::min((uint32_t)31, GetMinTrailingZeros(TCExpr));

ConstantInt *Result = TC->getValue();

// Guard against huge trip counts (this requires checking
// for zero to handle the case where the trip count == -1 and the
// addition wraps).
if (!Result || Result->getValue().getActiveBits() > 32 ||
    Result->getValue().getActiveBits() == 0)
  return 1;

return (unsigned)Result->getZExtValue();
6872}

6874const SCEV *ScalarEvolution::getExitCount(const Loop *L,
                                        const BasicBlock *ExitingBlock,
                                        ExitCountKind Kind) {
switch (Kind) {
case Exact:
case SymbolicMaximum:
  return getBackedgeTakenInfo(L).getExact(ExitingBlock, this);
case ConstantMaximum:
  return getBackedgeTakenInfo(L).getConstantMax(ExitingBlock, this);
};
llvm_unreachable("Invalid ExitCountKind!")::llvm::llvm_unreachable_internal("Invalid ExitCountKind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6884);
6885}

6887const SCEV *
6888ScalarEvolution::getPredicatedBackedgeTakenCount(const Loop *L,
                                               SCEVUnionPredicate &Preds) {
return getPredicatedBackedgeTakenInfo(L).getExact(L, this, &Preds);
6891}

6893const SCEV *ScalarEvolution::getBackedgeTakenCount(const Loop *L,
                                                 ExitCountKind Kind) {
switch (Kind) {
case Exact:
  return getBackedgeTakenInfo(L).getExact(L, this);
case ConstantMaximum:
  return getBackedgeTakenInfo(L).getConstantMax(this);
case SymbolicMaximum:
  return getBackedgeTakenInfo(L).getSymbolicMax(L, this);
};
llvm_unreachable("Invalid ExitCountKind!")::llvm::llvm_unreachable_internal("Invalid ExitCountKind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6903);
6904}

6906bool ScalarEvolution::isBackedgeTakenCountMaxOrZero(const Loop *L) {
return getBackedgeTakenInfo(L).isConstantMaxOrZero(this);
6908}

6910/// Push PHI nodes in the header of the given loop onto the given Worklist.
6911static void
6912PushLoopPHIs(const Loop *L, SmallVectorImpl<Instruction *> &Worklist) {
BasicBlock *Header = L->getHeader();

// Push all Loop-header PHIs onto the Worklist stack.
for (PHINode &PN : Header->phis())
  Worklist.push_back(&PN);
6918}

6920const ScalarEvolution::BackedgeTakenInfo &
6921ScalarEvolution::getPredicatedBackedgeTakenInfo(const Loop *L) {
auto &BTI = getBackedgeTakenInfo(L);
if (BTI.hasFullInfo())
  return BTI;

auto Pair = PredicatedBackedgeTakenCounts.insert({L, BackedgeTakenInfo()});

if (!Pair.second)
  return Pair.first->second;

BackedgeTakenInfo Result =
    computeBackedgeTakenCount(L, /*AllowPredicates=*/true);

return PredicatedBackedgeTakenCounts.find(L)->second = std::move(Result);
6935}

6937ScalarEvolution::BackedgeTakenInfo &
6938ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
// Initially insert an invalid entry for this loop. If the insertion
// succeeds, proceed to actually compute a backedge-taken count and
// update the value. The temporary CouldNotCompute value tells SCEV
// code elsewhere that it shouldn't attempt to request a new
// backedge-taken count, which could result in infinite recursion.
std::pair<DenseMap<const Loop *, BackedgeTakenInfo>::iterator, bool> Pair =
    BackedgeTakenCounts.insert({L, BackedgeTakenInfo()});
if (!Pair.second)
  return Pair.first->second;

// computeBackedgeTakenCount may allocate memory for its result. Inserting it
// into the BackedgeTakenCounts map transfers ownership. Otherwise, the result
// must be cleared in this scope.
BackedgeTakenInfo Result = computeBackedgeTakenCount(L);

// In product build, there are no usage of statistic.
(void)NumTripCountsComputed;
(void)NumTripCountsNotComputed;
6957#if LLVM_ENABLE_STATS1 || !defined(NDEBUG)
const SCEV *BEExact = Result.getExact(L, this);
if (BEExact != getCouldNotCompute()) {
  assert(isLoopInvariant(BEExact, L) &&((isLoopInvariant(BEExact, L) && isLoopInvariant(Result
.getConstantMax(this), L) && "Computed backedge-taken count isn't loop invariant for loop!"
) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(BEExact, L) && isLoopInvariant(Result.getConstantMax(this), L) && \"Computed backedge-taken count isn't loop invariant for loop!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6962, __PRETTY_FUNCTION__))
         isLoopInvariant(Result.getConstantMax(this), L) &&((isLoopInvariant(BEExact, L) && isLoopInvariant(Result
.getConstantMax(this), L) && "Computed backedge-taken count isn't loop invariant for loop!"
) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(BEExact, L) && isLoopInvariant(Result.getConstantMax(this), L) && \"Computed backedge-taken count isn't loop invariant for loop!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6962, __PRETTY_FUNCTION__))
         "Computed backedge-taken count isn't loop invariant for loop!")((isLoopInvariant(BEExact, L) && isLoopInvariant(Result
.getConstantMax(this), L) && "Computed backedge-taken count isn't loop invariant for loop!"
) ? static_cast<void> (0) : __assert_fail ("isLoopInvariant(BEExact, L) && isLoopInvariant(Result.getConstantMax(this), L) && \"Computed backedge-taken count isn't loop invariant for loop!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 6962, __PRETTY_FUNCTION__));
  ++NumTripCountsComputed;
} else if (Result.getConstantMax(this) == getCouldNotCompute() &&
           isa<PHINode>(L->getHeader()->begin())) {
  // Only count loops that have phi nodes as not being computable.
  ++NumTripCountsNotComputed;
}
6969#endif // LLVM_ENABLE_STATS || !defined(NDEBUG)

// Now that we know more about the trip count for this loop, forget any
// existing SCEV values for PHI nodes in this loop since they are only
// conservative estimates made without the benefit of trip count
// information. This is similar to the code in forgetLoop, except that
// it handles SCEVUnknown PHI nodes specially.
if (Result.hasAnyInfo()) {
  SmallVector<Instruction *, 16> Worklist;
  PushLoopPHIs(L, Worklist);

  SmallPtrSet<Instruction *, 8> Discovered;
  while (!Worklist.empty()) {
    Instruction *I = Worklist.pop_back_val();

    ValueExprMapType::iterator It =
      ValueExprMap.find_as(static_cast<Value *>(I));
    if (It != ValueExprMap.end()) {
      const SCEV *Old = It->second;

      // SCEVUnknown for a PHI either means that it has an unrecognized
      // structure, or it's a PHI that's in the progress of being computed
      // by createNodeForPHI.  In the former case, additional loop trip
      // count information isn't going to change anything. In the later
      // case, createNodeForPHI will perform the necessary updates on its
      // own when it gets to that point.
      if (!isa<PHINode>(I) || !isa<SCEVUnknown>(Old)) {
        eraseValueFromMap(It->first);
        forgetMemoizedResults(Old);
      }
      if (PHINode *PN = dyn_cast<PHINode>(I))
        ConstantEvolutionLoopExitValue.erase(PN);
    }

    // Since we don't need to invalidate anything for correctness and we're
    // only invalidating to make SCEV's results more precise, we get to stop
    // early to avoid invalidating too much.  This is especially important in
    // cases like:
    //
    //   %v = f(pn0, pn1) // pn0 and pn1 used through some other phi node
    // loop0:
    //   %pn0 = phi
    //   ...
    // loop1:
    //   %pn1 = phi
    //   ...
    //
    // where both loop0 and loop1's backedge taken count uses the SCEV
    // expression for %v.  If we don't have the early stop below then in cases
    // like the above, getBackedgeTakenInfo(loop1) will clear out the trip
    // count for loop0 and getBackedgeTakenInfo(loop0) will clear out the trip
    // count for loop1, effectively nullifying SCEV's trip count cache.
    for (auto *U : I->users())
      if (auto *I = dyn_cast<Instruction>(U)) {
        auto *LoopForUser = LI.getLoopFor(I->getParent());
        if (LoopForUser && L->contains(LoopForUser) &&
            Discovered.insert(I).second)
          Worklist.push_back(I);
      }
  }
}

// Re-lookup the insert position, since the call to
// computeBackedgeTakenCount above could result in a
// recusive call to getBackedgeTakenInfo (on a different
// loop), which would invalidate the iterator computed
// earlier.
return BackedgeTakenCounts.find(L)->second = std::move(Result);
7037}

7039void ScalarEvolution::forgetAllLoops() {
// This method is intended to forget all info about loops. It should
// invalidate caches as if the following happened:
// - The trip counts of all loops have changed arbitrarily
// - Every llvm::Value has been updated in place to produce a different
// result.
BackedgeTakenCounts.clear();
PredicatedBackedgeTakenCounts.clear();
LoopPropertiesCache.clear();
ConstantEvolutionLoopExitValue.clear();
ValueExprMap.clear();
ValuesAtScopes.clear();
LoopDispositions.clear();
BlockDispositions.clear();
UnsignedRanges.clear();
SignedRanges.clear();
ExprValueMap.clear();
HasRecMap.clear();
MinTrailingZerosCache.clear();
PredicatedSCEVRewrites.clear();
7059}

7061void ScalarEvolution::forgetLoop(const Loop *L) {
// Drop any stored trip count value.
auto RemoveLoopFromBackedgeMap =
    [](DenseMap<const Loop *, BackedgeTakenInfo> &Map, const Loop *L) {
      auto BTCPos = Map.find(L);
      if (BTCPos != Map.end()) {
        BTCPos->second.clear();
        Map.erase(BTCPos);
      }
    };

SmallVector<const Loop *, 16> LoopWorklist(1, L);
SmallVector<Instruction *, 32> Worklist;
SmallPtrSet<Instruction *, 16> Visited;

// Iterate over all the loops and sub-loops to drop SCEV information.
while (!LoopWorklist.empty()) {
  auto *CurrL = LoopWorklist.pop_back_val();

  RemoveLoopFromBackedgeMap(BackedgeTakenCounts, CurrL);
  RemoveLoopFromBackedgeMap(PredicatedBackedgeTakenCounts, CurrL);

  // Drop information about predicated SCEV rewrites for this loop.
  for (auto I = PredicatedSCEVRewrites.begin();
       I != PredicatedSCEVRewrites.end();) {
    std::pair<const SCEV *, const Loop *> Entry = I->first;
    if (Entry.second == CurrL)
      PredicatedSCEVRewrites.erase(I++);
    else
      ++I;
  }

  auto LoopUsersItr = LoopUsers.find(CurrL);
  if (LoopUsersItr != LoopUsers.end()) {
    for (auto *S : LoopUsersItr->second)
      forgetMemoizedResults(S);
    LoopUsers.erase(LoopUsersItr);
  }

  // Drop information about expressions based on loop-header PHIs.
  PushLoopPHIs(CurrL, Worklist);

  while (!Worklist.empty()) {
    Instruction *I = Worklist.pop_back_val();
    if (!Visited.insert(I).second)
      continue;

    ValueExprMapType::iterator It =
        ValueExprMap.find_as(static_cast<Value *>(I));
    if (It != ValueExprMap.end()) {
      eraseValueFromMap(It->first);
      forgetMemoizedResults(It->second);
      if (PHINode *PN = dyn_cast<PHINode>(I))
        ConstantEvolutionLoopExitValue.erase(PN);
    }

    PushDefUseChildren(I, Worklist);
  }

  LoopPropertiesCache.erase(CurrL);
  // Forget all contained loops too, to avoid dangling entries in the
  // ValuesAtScopes map.
  LoopWorklist.append(CurrL->begin(), CurrL->end());
}
7125}

7127void ScalarEvolution::forgetTopmostLoop(const Loop *L) {
while (Loop *Parent = L->getParentLoop())
  L = Parent;
forgetLoop(L);
7131}

7133void ScalarEvolution::forgetValue(Value *V) {
Instruction *I = dyn_cast<Instruction>(V);
if (!I) return;

// Drop information about expressions based on loop-header PHIs.
SmallVector<Instruction *, 16> Worklist;
Worklist.push_back(I);

SmallPtrSet<Instruction *, 8> Visited;
while (!Worklist.empty()) {
  I = Worklist.pop_back_val();
  if (!Visited.insert(I).second)
    continue;

  ValueExprMapType::iterator It =
    ValueExprMap.find_as(static_cast<Value *>(I));
  if (It != ValueExprMap.end()) {
    eraseValueFromMap(It->first);
    forgetMemoizedResults(It->second);
    if (PHINode *PN = dyn_cast<PHINode>(I))
      ConstantEvolutionLoopExitValue.erase(PN);
  }

  PushDefUseChildren(I, Worklist);
}
7158}

7160void ScalarEvolution::forgetLoopDispositions(const Loop *L) {
LoopDispositions.clear();
7162}

7164/// Get the exact loop backedge taken count considering all loop exits. A
7165/// computable result can only be returned for loops with all exiting blocks
7166/// dominating the latch. howFarToZero assumes that the limit of each loop test
7167/// is never skipped. This is a valid assumption as long as the loop exits via
7168/// that test. For precise results, it is the caller's responsibility to specify
7169/// the relevant loop exiting block using getExact(ExitingBlock, SE).
7170const SCEV *
7171ScalarEvolution::BackedgeTakenInfo::getExact(const Loop *L, ScalarEvolution *SE,
                                           SCEVUnionPredicate *Preds) const {
// If any exits were not computable, the loop is not computable.
if (!isComplete() || ExitNotTaken.empty())
  return SE->getCouldNotCompute();

const BasicBlock *Latch = L->getLoopLatch();
// All exiting blocks we have collected must dominate the only backedge.
if (!Latch)
  return SE->getCouldNotCompute();

// All exiting blocks we have gathered dominate loop's latch, so exact trip
// count is simply a minimum out of all these calculated exit counts.
SmallVector<const SCEV *, 2> Ops;
for (auto &ENT : ExitNotTaken) {
  const SCEV *BECount = ENT.ExactNotTaken;
  assert(BECount != SE->getCouldNotCompute() && "Bad exit SCEV!")((BECount != SE->getCouldNotCompute() && "Bad exit SCEV!"
) ? static_cast<void> (0) : __assert_fail ("BECount != SE->getCouldNotCompute() && \"Bad exit SCEV!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7187, __PRETTY_FUNCTION__));
  assert(SE->DT.dominates(ENT.ExitingBlock, Latch) &&((SE->DT.dominates(ENT.ExitingBlock, Latch) && "We should only have known counts for exiting blocks that dominate "
 "latch!") ? static_cast<void> (0) : __assert_fail ("SE->DT.dominates(ENT.ExitingBlock, Latch) && \"We should only have known counts for exiting blocks that dominate \" \"latch!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7190, __PRETTY_FUNCTION__))
         "We should only have known counts for exiting blocks that dominate "((SE->DT.dominates(ENT.ExitingBlock, Latch) && "We should only have known counts for exiting blocks that dominate "
 "latch!") ? static_cast<void> (0) : __assert_fail ("SE->DT.dominates(ENT.ExitingBlock, Latch) && \"We should only have known counts for exiting blocks that dominate \" \"latch!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7190, __PRETTY_FUNCTION__))
         "latch!")((SE->DT.dominates(ENT.ExitingBlock, Latch) && "We should only have known counts for exiting blocks that dominate "
 "latch!") ? static_cast<void> (0) : __assert_fail ("SE->DT.dominates(ENT.ExitingBlock, Latch) && \"We should only have known counts for exiting blocks that dominate \" \"latch!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7190, __PRETTY_FUNCTION__));

  Ops.push_back(BECount);

  if (Preds && !ENT.hasAlwaysTruePredicate())
    Preds->add(ENT.Predicate.get());

  assert((Preds || ENT.hasAlwaysTruePredicate()) &&(((Preds || ENT.hasAlwaysTruePredicate()) && "Predicate should be always true!"
) ? static_cast<void> (0) : __assert_fail ("(Preds || ENT.hasAlwaysTruePredicate()) && \"Predicate should be always true!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7198, __PRETTY_FUNCTION__))
         "Predicate should be always true!")(((Preds || ENT.hasAlwaysTruePredicate()) && "Predicate should be always true!"
) ? static_cast<void> (0) : __assert_fail ("(Preds || ENT.hasAlwaysTruePredicate()) && \"Predicate should be always true!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7198, __PRETTY_FUNCTION__));
}

return SE->getUMinFromMismatchedTypes(Ops);
7202}

7204/// Get the exact not taken count for this loop exit.
7205const SCEV *
7206ScalarEvolution::BackedgeTakenInfo::getExact(const BasicBlock *ExitingBlock,
                                           ScalarEvolution *SE) const {
for (auto &ENT : ExitNotTaken)
  if (ENT.ExitingBlock == ExitingBlock && ENT.hasAlwaysTruePredicate())
    return ENT.ExactNotTaken;

return SE->getCouldNotCompute();
7213}

7215const SCEV *ScalarEvolution::BackedgeTakenInfo::getConstantMax(
  const BasicBlock *ExitingBlock, ScalarEvolution *SE) const {
for (auto &ENT : ExitNotTaken)
  if (ENT.ExitingBlock == ExitingBlock && ENT.hasAlwaysTruePredicate())
    return ENT.MaxNotTaken;

return SE->getCouldNotCompute();
7222}

7224/// getConstantMax - Get the constant max backedge taken count for the loop.
7225const SCEV *
7226ScalarEvolution::BackedgeTakenInfo::getConstantMax(ScalarEvolution *SE) const {
auto PredicateNotAlwaysTrue = [](const ExitNotTakenInfo &ENT) {
  return !ENT.hasAlwaysTruePredicate();
};

if (any_of(ExitNotTaken, PredicateNotAlwaysTrue) || !getConstantMax())
  return SE->getCouldNotCompute();

assert((isa<SCEVCouldNotCompute>(getConstantMax()) ||(((isa<SCEVCouldNotCompute>(getConstantMax()) || isa<
SCEVConstant>(getConstantMax())) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(getConstantMax()) || isa<SCEVConstant>(getConstantMax())) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7236, __PRETTY_FUNCTION__))
        isa<SCEVConstant>(getConstantMax())) &&(((isa<SCEVCouldNotCompute>(getConstantMax()) || isa<
SCEVConstant>(getConstantMax())) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(getConstantMax()) || isa<SCEVConstant>(getConstantMax())) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7236, __PRETTY_FUNCTION__))
       "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(getConstantMax()) || isa<
SCEVConstant>(getConstantMax())) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(getConstantMax()) || isa<SCEVConstant>(getConstantMax())) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7236, __PRETTY_FUNCTION__));
return getConstantMax();
7238}

7240const SCEV *
7241ScalarEvolution::BackedgeTakenInfo::getSymbolicMax(const Loop *L,
                                                 ScalarEvolution *SE) {
if (!SymbolicMax)
  SymbolicMax = SE->computeSymbolicMaxBackedgeTakenCount(L);
return SymbolicMax;
7246}

7248bool ScalarEvolution::BackedgeTakenInfo::isConstantMaxOrZero(
  ScalarEvolution *SE) const {
auto PredicateNotAlwaysTrue = [](const ExitNotTakenInfo &ENT) {
  return !ENT.hasAlwaysTruePredicate();
};
return MaxOrZero && !any_of(ExitNotTaken, PredicateNotAlwaysTrue);
7254}

7256bool ScalarEvolution::BackedgeTakenInfo::hasOperand(const SCEV *S,
                                                  ScalarEvolution *SE) const {
if (getConstantMax() && getConstantMax() != SE->getCouldNotCompute() &&
    SE->hasOperand(getConstantMax(), S))
  return true;

for (auto &ENT : ExitNotTaken)
  if (ENT.ExactNotTaken != SE->getCouldNotCompute() &&
      SE->hasOperand(ENT.ExactNotTaken, S))
    return true;

return false;
7268}

7270ScalarEvolution::ExitLimit::ExitLimit(const SCEV *E)
  : ExactNotTaken(E), MaxNotTaken(E) {
assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7274, __PRETTY_FUNCTION__))
        isa<SCEVConstant>(MaxNotTaken)) &&(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7274, __PRETTY_FUNCTION__))
       "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7274, __PRETTY_FUNCTION__));
7275}

7277ScalarEvolution::ExitLimit::ExitLimit(
  const SCEV *E, const SCEV *M, bool MaxOrZero,
  ArrayRef<const SmallPtrSetImpl<const SCEVPredicate *> *> PredSetList)
  : ExactNotTaken(E), MaxNotTaken(M), MaxOrZero(MaxOrZero) {
assert((isa<SCEVCouldNotCompute>(ExactNotTaken) ||(((isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute
>(MaxNotTaken)) && "Exact is not allowed to be less precise than Max"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute>(MaxNotTaken)) && \"Exact is not allowed to be less precise than Max\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7283, __PRETTY_FUNCTION__))
        !isa<SCEVCouldNotCompute>(MaxNotTaken)) &&(((isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute
>(MaxNotTaken)) && "Exact is not allowed to be less precise than Max"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute>(MaxNotTaken)) && \"Exact is not allowed to be less precise than Max\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7283, __PRETTY_FUNCTION__))
       "Exact is not allowed to be less precise than Max")(((isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute
>(MaxNotTaken)) && "Exact is not allowed to be less precise than Max"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute>(MaxNotTaken)) && \"Exact is not allowed to be less precise than Max\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7283, __PRETTY_FUNCTION__));
assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7286, __PRETTY_FUNCTION__))
        isa<SCEVConstant>(MaxNotTaken)) &&(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7286, __PRETTY_FUNCTION__))
       "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7286, __PRETTY_FUNCTION__));
for (auto *PredSet : PredSetList)
  for (auto *P : *PredSet)
    addPredicate(P);
7290}

7292ScalarEvolution::ExitLimit::ExitLimit(
  const SCEV *E, const SCEV *M, bool MaxOrZero,
  const SmallPtrSetImpl<const SCEVPredicate *> &PredSet)
  : ExitLimit(E, M, MaxOrZero, {&PredSet}) {
assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7298, __PRETTY_FUNCTION__))
        isa<SCEVConstant>(MaxNotTaken)) &&(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7298, __PRETTY_FUNCTION__))
       "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7298, __PRETTY_FUNCTION__));
7299}

7301ScalarEvolution::ExitLimit::ExitLimit(const SCEV *E, const SCEV *M,
                                    bool MaxOrZero)
  : ExitLimit(E, M, MaxOrZero, None) {
assert((isa<SCEVCouldNotCompute>(MaxNotTaken) ||(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7306, __PRETTY_FUNCTION__))
        isa<SCEVConstant>(MaxNotTaken)) &&(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7306, __PRETTY_FUNCTION__))
       "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant
>(MaxNotTaken)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(MaxNotTaken) || isa<SCEVConstant>(MaxNotTaken)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7306, __PRETTY_FUNCTION__));
7307}

7309/// Allocate memory for BackedgeTakenInfo and copy the not-taken count of each
7310/// computable exit into a persistent ExitNotTakenInfo array.
7311ScalarEvolution::BackedgeTakenInfo::BackedgeTakenInfo(
  ArrayRef<ScalarEvolution::BackedgeTakenInfo::EdgeExitInfo> ExitCounts,
  bool IsComplete, const SCEV *ConstantMax, bool MaxOrZero)
  : ConstantMax(ConstantMax), IsComplete(IsComplete), MaxOrZero(MaxOrZero) {
using EdgeExitInfo = ScalarEvolution::BackedgeTakenInfo::EdgeExitInfo;

ExitNotTaken.reserve(ExitCounts.size());
std::transform(
    ExitCounts.begin(), ExitCounts.end(), std::back_inserter(ExitNotTaken),
    [&](const EdgeExitInfo &EEI) {
      BasicBlock *ExitBB = EEI.first;
      const ExitLimit &EL = EEI.second;
      if (EL.Predicates.empty())
        return ExitNotTakenInfo(ExitBB, EL.ExactNotTaken, EL.MaxNotTaken,
                                nullptr);

      std::unique_ptr<SCEVUnionPredicate> Predicate(new SCEVUnionPredicate);
      for (auto *Pred : EL.Predicates)
        Predicate->add(Pred);

      return ExitNotTakenInfo(ExitBB, EL.ExactNotTaken, EL.MaxNotTaken,
                              std::move(Predicate));
    });
assert((isa<SCEVCouldNotCompute>(ConstantMax) ||(((isa<SCEVCouldNotCompute>(ConstantMax) || isa<SCEVConstant
>(ConstantMax)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(ConstantMax) || isa<SCEVConstant>(ConstantMax)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7336, __PRETTY_FUNCTION__))
        isa<SCEVConstant>(ConstantMax)) &&(((isa<SCEVCouldNotCompute>(ConstantMax) || isa<SCEVConstant
>(ConstantMax)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(ConstantMax) || isa<SCEVConstant>(ConstantMax)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7336, __PRETTY_FUNCTION__))
       "No point in having a non-constant max backedge taken count!")(((isa<SCEVCouldNotCompute>(ConstantMax) || isa<SCEVConstant
>(ConstantMax)) && "No point in having a non-constant max backedge taken count!"
) ? static_cast<void> (0) : __assert_fail ("(isa<SCEVCouldNotCompute>(ConstantMax) || isa<SCEVConstant>(ConstantMax)) && \"No point in having a non-constant max backedge taken count!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7336, __PRETTY_FUNCTION__));
7337}

7339/// Invalidate this result and free the ExitNotTakenInfo array.
7340void ScalarEvolution::BackedgeTakenInfo::clear() {
ExitNotTaken.clear();
7342}

7344/// Compute the number of times the backedge of the specified loop will execute.
7345ScalarEvolution::BackedgeTakenInfo
7346ScalarEvolution::computeBackedgeTakenCount(const Loop *L,
                                         bool AllowPredicates) {
SmallVector<BasicBlock *, 8> ExitingBlocks;
L->getExitingBlocks(ExitingBlocks);

using EdgeExitInfo = ScalarEvolution::BackedgeTakenInfo::EdgeExitInfo;

SmallVector<EdgeExitInfo, 4> ExitCounts;
bool CouldComputeBECount = true;
BasicBlock *Latch = L->getLoopLatch(); // may be NULL.
const SCEV *MustExitMaxBECount = nullptr;
const SCEV *MayExitMaxBECount = nullptr;
bool MustExitMaxOrZero = false;

// Compute the ExitLimit for each loop exit. Use this to populate ExitCounts
// and compute maxBECount.
// Do a union of all the predicates here.
for (unsigned i = 0, e = ExitingBlocks.size(); i != e; ++i) {
  BasicBlock *ExitBB = ExitingBlocks[i];

  // We canonicalize untaken exits to br (constant), ignore them so that
  // proving an exit untaken doesn't negatively impact our ability to reason
  // about the loop as whole.
  if (auto *BI = dyn_cast<BranchInst>(ExitBB->getTerminator()))
    if (auto *CI = dyn_cast<ConstantInt>(BI->getCondition())) {
      bool ExitIfTrue = !L->contains(BI->getSuccessor(0));
      if ((ExitIfTrue && CI->isZero()) || (!ExitIfTrue && CI->isOne()))
        continue;
    }

  ExitLimit EL = computeExitLimit(L, ExitBB, AllowPredicates);

  assert((AllowPredicates || EL.Predicates.empty()) &&(((AllowPredicates || EL.Predicates.empty()) && "Predicated exit limit when predicates are not allowed!"
) ? static_cast<void> (0) : __assert_fail ("(AllowPredicates || EL.Predicates.empty()) && \"Predicated exit limit when predicates are not allowed!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7379, __PRETTY_FUNCTION__))
         "Predicated exit limit when predicates are not allowed!")(((AllowPredicates || EL.Predicates.empty()) && "Predicated exit limit when predicates are not allowed!"
) ? static_cast<void> (0) : __assert_fail ("(AllowPredicates || EL.Predicates.empty()) && \"Predicated exit limit when predicates are not allowed!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7379, __PRETTY_FUNCTION__));

  // 1. For each exit that can be computed, add an entry to ExitCounts.
  // CouldComputeBECount is true only if all exits can be computed.
  if (EL.ExactNotTaken == getCouldNotCompute())
    // We couldn't compute an exact value for this exit, so
    // we won't be able to compute an exact value for the loop.
    CouldComputeBECount = false;
  else
    ExitCounts.emplace_back(ExitBB, EL);

  // 2. Derive the loop's MaxBECount from each exit's max number of
  // non-exiting iterations. Partition the loop exits into two kinds:
  // LoopMustExits and LoopMayExits.
  //
  // If the exit dominates the loop latch, it is a LoopMustExit otherwise it
  // is a LoopMayExit.  If any computable LoopMustExit is found, then
  // MaxBECount is the minimum EL.MaxNotTaken of computable
  // LoopMustExits. Otherwise, MaxBECount is conservatively the maximum
  // EL.MaxNotTaken, where CouldNotCompute is considered greater than any
  // computable EL.MaxNotTaken.
  if (EL.MaxNotTaken != getCouldNotCompute() && Latch &&
      DT.dominates(ExitBB, Latch)) {
    if (!MustExitMaxBECount) {
      MustExitMaxBECount = EL.MaxNotTaken;
      MustExitMaxOrZero = EL.MaxOrZero;
    } else {
      MustExitMaxBECount =
          getUMinFromMismatchedTypes(MustExitMaxBECount, EL.MaxNotTaken);
    }
  } else if (MayExitMaxBECount != getCouldNotCompute()) {
    if (!MayExitMaxBECount || EL.MaxNotTaken == getCouldNotCompute())
      MayExitMaxBECount = EL.MaxNotTaken;
    else {
      MayExitMaxBECount =
          getUMaxFromMismatchedTypes(MayExitMaxBECount, EL.MaxNotTaken);
    }
  }
}
const SCEV *MaxBECount = MustExitMaxBECount ? MustExitMaxBECount :
  (MayExitMaxBECount ? MayExitMaxBECount : getCouldNotCompute());
// The loop backedge will be taken the maximum or zero times if there's
// a single exit that must be taken the maximum or zero times.
bool MaxOrZero = (MustExitMaxOrZero && ExitingBlocks.size() == 1);
return BackedgeTakenInfo(std::move(ExitCounts), CouldComputeBECount,
                         MaxBECount, MaxOrZero);
7425}

7427ScalarEvolution::ExitLimit
7428ScalarEvolution::computeExitLimit(const Loop *L, BasicBlock *ExitingBlock,
                                    bool AllowPredicates) {
assert(L->contains(ExitingBlock) && "Exit count for non-loop block?")((L->contains(ExitingBlock) && "Exit count for non-loop block?"
) ? static_cast<void> (0) : __assert_fail ("L->contains(ExitingBlock) && \"Exit count for non-loop block?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7430, __PRETTY_FUNCTION__));
// If our exiting block does not dominate the latch, then its connection with
// loop's exit limit may be far from trivial.
const BasicBlock *Latch = L->getLoopLatch();
if (!Latch || !DT.dominates(ExitingBlock, Latch))
  return getCouldNotCompute();

bool IsOnlyExit = (L->getExitingBlock() != nullptr);
Instruction *Term = ExitingBlock->getTerminator();
if (BranchInst *BI = dyn_cast<BranchInst>(Term)) {
  assert(BI->isConditional() && "If unconditional, it can't be in loop!")((BI->isConditional() && "If unconditional, it can't be in loop!"
) ? static_cast<void> (0) : __assert_fail ("BI->isConditional() && \"If unconditional, it can't be in loop!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7440, __PRETTY_FUNCTION__));
  bool ExitIfTrue = !L->contains(BI->getSuccessor(0));
  assert(ExitIfTrue == L->contains(BI->getSuccessor(1)) &&((ExitIfTrue == L->contains(BI->getSuccessor(1)) &&
 "It should have one successor in loop and one exit block!") ?
 static_cast<void> (0) : __assert_fail ("ExitIfTrue == L->contains(BI->getSuccessor(1)) && \"It should have one successor in loop and one exit block!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7443, __PRETTY_FUNCTION__))
         "It should have one successor in loop and one exit block!")((ExitIfTrue == L->contains(BI->getSuccessor(1)) &&
 "It should have one successor in loop and one exit block!") ?
 static_cast<void> (0) : __assert_fail ("ExitIfTrue == L->contains(BI->getSuccessor(1)) && \"It should have one successor in loop and one exit block!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7443, __PRETTY_FUNCTION__));
  // Proceed to the next level to examine the exit condition expression.
  return computeExitLimitFromCond(
      L, BI->getCondition(), ExitIfTrue,
      /*ControlsExit=*/IsOnlyExit, AllowPredicates);
}

if (SwitchInst *SI = dyn_cast<SwitchInst>(Term)) {
  // For switch, make sure that there is a single exit from the loop.
  BasicBlock *Exit = nullptr;
  for (auto *SBB : successors(ExitingBlock))
    if (!L->contains(SBB)) {
      if (Exit) // Multiple exit successors.
        return getCouldNotCompute();
      Exit = SBB;
    }
  assert(Exit && "Exiting block must have at least one exit")((Exit && "Exiting block must have at least one exit"
) ? static_cast<void> (0) : __assert_fail ("Exit && \"Exiting block must have at least one exit\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7459, __PRETTY_FUNCTION__));
  return computeExitLimitFromSingleExitSwitch(L, SI, Exit,
                                              /*ControlsExit=*/IsOnlyExit);
}

return getCouldNotCompute();
7465}

7467ScalarEvolution::ExitLimit ScalarEvolution::computeExitLimitFromCond(
  const Loop *L, Value *ExitCond, bool ExitIfTrue,
  bool ControlsExit, bool AllowPredicates) {
ScalarEvolution::ExitLimitCacheTy Cache(L, ExitIfTrue, AllowPredicates);
return computeExitLimitFromCondCached(Cache, L, ExitCond, ExitIfTrue,
                                      ControlsExit, AllowPredicates);
7473}

7475Optional<ScalarEvolution::ExitLimit>
7476ScalarEvolution::ExitLimitCache::find(const Loop *L, Value *ExitCond,
                                    bool ExitIfTrue, bool ControlsExit,
                                    bool AllowPredicates) {
(void)this->L;
(void)this->ExitIfTrue;
(void)this->AllowPredicates;

assert(this->L == L && this->ExitIfTrue == ExitIfTrue &&((this->L == L && this->ExitIfTrue == ExitIfTrue
 && this->AllowPredicates == AllowPredicates &&
 "Variance in assumed invariant key components!") ? static_cast
<void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7485, __PRETTY_FUNCTION__))
       this->AllowPredicates == AllowPredicates &&((this->L == L && this->ExitIfTrue == ExitIfTrue
 && this->AllowPredicates == AllowPredicates &&
 "Variance in assumed invariant key components!") ? static_cast
<void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7485, __PRETTY_FUNCTION__))
       "Variance in assumed invariant key components!")((this->L == L && this->ExitIfTrue == ExitIfTrue
 && this->AllowPredicates == AllowPredicates &&
 "Variance in assumed invariant key components!") ? static_cast
<void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7485, __PRETTY_FUNCTION__));
auto Itr = TripCountMap.find({ExitCond, ControlsExit});
if (Itr == TripCountMap.end())
  return None;
return Itr->second;
7490}

7492void ScalarEvolution::ExitLimitCache::insert(const Loop *L, Value *ExitCond,
                                           bool ExitIfTrue,
                                           bool ControlsExit,
                                           bool AllowPredicates,
                                           const ExitLimit &EL) {
assert(this->L == L && this->ExitIfTrue == ExitIfTrue &&((this->L == L && this->ExitIfTrue == ExitIfTrue
 && this->AllowPredicates == AllowPredicates &&
 "Variance in assumed invariant key components!") ? static_cast
<void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7499, __PRETTY_FUNCTION__))
       this->AllowPredicates == AllowPredicates &&((this->L == L && this->ExitIfTrue == ExitIfTrue
 && this->AllowPredicates == AllowPredicates &&
 "Variance in assumed invariant key components!") ? static_cast
<void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7499, __PRETTY_FUNCTION__))
       "Variance in assumed invariant key components!")((this->L == L && this->ExitIfTrue == ExitIfTrue
 && this->AllowPredicates == AllowPredicates &&
 "Variance in assumed invariant key components!") ? static_cast
<void> (0) : __assert_fail ("this->L == L && this->ExitIfTrue == ExitIfTrue && this->AllowPredicates == AllowPredicates && \"Variance in assumed invariant key components!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7499, __PRETTY_FUNCTION__));

auto InsertResult = TripCountMap.insert({{ExitCond, ControlsExit}, EL});
assert(InsertResult.second && "Expected successful insertion!")((InsertResult.second && "Expected successful insertion!"
) ? static_cast<void> (0) : __assert_fail ("InsertResult.second && \"Expected successful insertion!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7502, __PRETTY_FUNCTION__));
(void)InsertResult;
(void)ExitIfTrue;
7505}

7507ScalarEvolution::ExitLimit ScalarEvolution::computeExitLimitFromCondCached(
  ExitLimitCacheTy &Cache, const Loop *L, Value *ExitCond, bool ExitIfTrue,
  bool ControlsExit, bool AllowPredicates) {

if (auto MaybeEL =
        Cache.find(L, ExitCond, ExitIfTrue, ControlsExit, AllowPredicates))
  return *MaybeEL;

ExitLimit EL = computeExitLimitFromCondImpl(Cache, L, ExitCond, ExitIfTrue,
                                            ControlsExit, AllowPredicates);
Cache.insert(L, ExitCond, ExitIfTrue, ControlsExit, AllowPredicates, EL);
return EL;
7519}

7521ScalarEvolution::ExitLimit ScalarEvolution::computeExitLimitFromCondImpl(
  ExitLimitCacheTy &Cache, const Loop *L, Value *ExitCond, bool ExitIfTrue,
  bool ControlsExit, bool AllowPredicates) {
// Handle BinOp conditions (And, Or).
if (auto LimitFromBinOp = computeExitLimitFromCondFromBinOp(
        Cache, L, ExitCond, ExitIfTrue, ControlsExit, AllowPredicates))
  return *LimitFromBinOp;

// With an icmp, it may be feasible to compute an exact backedge-taken count.
// Proceed to the next level to examine the icmp.
if (ICmpInst *ExitCondICmp = dyn_cast<ICmpInst>(ExitCond)) {
  ExitLimit EL =
      computeExitLimitFromICmp(L, ExitCondICmp, ExitIfTrue, ControlsExit);
  if (EL.hasFullInfo() || !AllowPredicates)
    return EL;

  // Try again, but use SCEV predicates this time.
  return computeExitLimitFromICmp(L, ExitCondICmp, ExitIfTrue, ControlsExit,
                                  /*AllowPredicates=*/true);
}

// Check for a constant condition. These are normally stripped out by
// SimplifyCFG, but ScalarEvolution may be used by a pass which wishes to
// preserve the CFG and is temporarily leaving constant conditions
// in place.
if (ConstantInt *CI = dyn_cast<ConstantInt>(ExitCond)) {
  if (ExitIfTrue == !CI->getZExtValue())
    // The backedge is always taken.
    return getCouldNotCompute();
  else
    // The backedge is never taken.
    return getZero(CI->getType());
}

// If it's not an integer or pointer comparison then compute it the hard way.
return computeExitCountExhaustively(L, ExitCond, ExitIfTrue);
7557}

7559Optional<ScalarEvolution::ExitLimit>
7560ScalarEvolution::computeExitLimitFromCondFromBinOp(
  ExitLimitCacheTy &Cache, const Loop *L, Value *ExitCond, bool ExitIfTrue,
  bool ControlsExit, bool AllowPredicates) {
// Check if the controlling expression for this loop is an And or Or.
if (auto *BO = dyn_cast<BinaryOperator>(ExitCond)) {
  if (BO->getOpcode() == Instruction::And)
    return computeExitLimitFromCondFromBinOpHelper(
        Cache, L, BO, !ExitIfTrue, ExitIfTrue, ControlsExit, AllowPredicates,
        ConstantInt::get(BO->getType(), 1));
  if (BO->getOpcode() == Instruction::Or)
    return computeExitLimitFromCondFromBinOpHelper(
        Cache, L, BO, ExitIfTrue, ExitIfTrue, ControlsExit, AllowPredicates,
        ConstantInt::get(BO->getType(), 0));
}
return None;
7575}

7577ScalarEvolution::ExitLimit
7578ScalarEvolution::computeExitLimitFromCondFromBinOpHelper(
  ExitLimitCacheTy &Cache, const Loop *L, BinaryOperator *BO,
  bool EitherMayExit, bool ExitIfTrue, bool ControlsExit,
  bool AllowPredicates, const Constant *NeutralElement) {
ExitLimit EL0 = computeExitLimitFromCondCached(
    Cache, L, BO->getOperand(0), ExitIfTrue, ControlsExit && !EitherMayExit,
    AllowPredicates);
ExitLimit EL1 = computeExitLimitFromCondCached(
    Cache, L, BO->getOperand(1), ExitIfTrue, ControlsExit && !EitherMayExit,
    AllowPredicates);
// Be robust against unsimplified IR for the form "op i1 X,
// NeutralElement"
if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(1)))
  return CI == NeutralElement ? EL0 : EL1;
if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(0)))
  return CI == NeutralElement ? EL1 : EL0;
const SCEV *BECount = getCouldNotCompute();
const SCEV *MaxBECount = getCouldNotCompute();
if (EitherMayExit) {
  // Both conditions must be same for the loop to continue executing.
  // Choose the less conservative count.
  if (EL0.ExactNotTaken == getCouldNotCompute() ||
      EL1.ExactNotTaken == getCouldNotCompute())
    BECount = getCouldNotCompute();
  else
    BECount =
        getUMinFromMismatchedTypes(EL0.ExactNotTaken, EL1.ExactNotTaken);
  if (EL0.MaxNotTaken == getCouldNotCompute())
    MaxBECount = EL1.MaxNotTaken;
  else if (EL1.MaxNotTaken == getCouldNotCompute())
    MaxBECount = EL0.MaxNotTaken;
  else
    MaxBECount = getUMinFromMismatchedTypes(EL0.MaxNotTaken, EL1.MaxNotTaken);
} else {
  // Both conditions must be same at the same time for the loop to exit.
  // For now, be conservative.
  if (EL0.ExactNotTaken == EL1.ExactNotTaken)
    BECount = EL0.ExactNotTaken;
}

// There are cases (e.g. PR26207) where computeExitLimitFromCond is able
// to be more aggressive when computing BECount than when computing
// MaxBECount.  In these cases it is possible for EL0.ExactNotTaken and
// EL1.ExactNotTaken to match, but for EL0.MaxNotTaken and EL1.MaxNotTaken
// to not.
if (isa<SCEVCouldNotCompute>(MaxBECount) &&
    !isa<SCEVCouldNotCompute>(BECount))
  MaxBECount = getConstant(getUnsignedRangeMax(BECount));

return ExitLimit(BECount, MaxBECount, false,
                 { &EL0.Predicates, &EL1.Predicates });
7629}

7631ScalarEvolution::ExitLimit
7632ScalarEvolution::computeExitLimitFromICmp(const Loop *L,
                                        ICmpInst *ExitCond,
                                        bool ExitIfTrue,
                                        bool ControlsExit,
                                        bool AllowPredicates) {
// If the condition was exit on true, convert the condition to exit on false
ICmpInst::Predicate Pred;
if (!ExitIfTrue)
  Pred = ExitCond->getPredicate();
else
  Pred = ExitCond->getInversePredicate();
const ICmpInst::Predicate OriginalPred = Pred;

// Handle common loops like: for (X = "string"; *X; ++X)
if (LoadInst *LI = dyn_cast<LoadInst>(ExitCond->getOperand(0)))
  if (Constant *RHS = dyn_cast<Constant>(ExitCond->getOperand(1))) {
    ExitLimit ItCnt =
      computeLoadConstantCompareExitLimit(LI, RHS, L, Pred);
    if (ItCnt.hasAnyInfo())
      return ItCnt;
  }

const SCEV *LHS = getSCEV(ExitCond->getOperand(0));
const SCEV *RHS = getSCEV(ExitCond->getOperand(1));

// Try to evaluate any dependencies out of the loop.
LHS = getSCEVAtScope(LHS, L);
RHS = getSCEVAtScope(RHS, L);

// At this point, we would like to compute how many iterations of the
// loop the predicate will return true for these inputs.
if (isLoopInvariant(LHS, L) && !isLoopInvariant(RHS, L)) {
  // If there is a loop-invariant, force it into the RHS.
  std::swap(LHS, RHS);
  Pred = ICmpInst::getSwappedPredicate(Pred);
}

// Simplify the operands before analyzing them.
(void)SimplifyICmpOperands(Pred, LHS, RHS);

// If we have a comparison of a chrec against a constant, try to use value
// ranges to answer this query.
if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS))
  if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(LHS))
    if (AddRec->getLoop() == L) {
      // Form the constant range.
      ConstantRange CompRange =
          ConstantRange::makeExactICmpRegion(Pred, RHSC->getAPInt());

      const SCEV *Ret = AddRec->getNumIterationsInRange(CompRange, *this);
      if (!isa<SCEVCouldNotCompute>(Ret)) return Ret;
    }

switch (Pred) {
case ICmpInst::ICMP_NE: {                     // while (X != Y)
  // Convert to: while (X-Y != 0)
  ExitLimit EL = howFarToZero(getMinusSCEV(LHS, RHS), L, ControlsExit,
                              AllowPredicates);
  if (EL.hasAnyInfo()) return EL;
  break;
}
case ICmpInst::ICMP_EQ: {                     // while (X == Y)
  // Convert to: while (X-Y == 0)
  ExitLimit EL = howFarToNonZero(getMinusSCEV(LHS, RHS), L);
  if (EL.hasAnyInfo()) return EL;
  break;
}
case ICmpInst::ICMP_SLT:
case ICmpInst::ICMP_ULT: {                    // while (X < Y)
  bool IsSigned = Pred == ICmpInst::ICMP_SLT;
  ExitLimit EL = howManyLessThans(LHS, RHS, L, IsSigned, ControlsExit,
                                  AllowPredicates);
  if (EL.hasAnyInfo()) return EL;
  break;
}
case ICmpInst::ICMP_SGT:
case ICmpInst::ICMP_UGT: {                    // while (X > Y)
  bool IsSigned = Pred == ICmpInst::ICMP_SGT;
  ExitLimit EL =
      howManyGreaterThans(LHS, RHS, L, IsSigned, ControlsExit,
                          AllowPredicates);
  if (EL.hasAnyInfo()) return EL;
  break;
}
default:
  break;
}

auto *ExhaustiveCount =
    computeExitCountExhaustively(L, ExitCond, ExitIfTrue);

if (!isa<SCEVCouldNotCompute>(ExhaustiveCount))
  return ExhaustiveCount;

return computeShiftCompareExitLimit(ExitCond->getOperand(0),
                                    ExitCond->getOperand(1), L, OriginalPred);
7728}

7730ScalarEvolution::ExitLimit
7731ScalarEvolution::computeExitLimitFromSingleExitSwitch(const Loop *L,
                                                    SwitchInst *Switch,
                                                    BasicBlock *ExitingBlock,
                                                    bool ControlsExit) {
assert(!L->contains(ExitingBlock) && "Not an exiting block!")((!L->contains(ExitingBlock) && "Not an exiting block!"
) ? static_cast<void> (0) : __assert_fail ("!L->contains(ExitingBlock) && \"Not an exiting block!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7735, __PRETTY_FUNCTION__));

// Give up if the exit is the default dest of a switch.
if (Switch->getDefaultDest() == ExitingBlock)
  return getCouldNotCompute();

assert(L->contains(Switch->getDefaultDest()) &&((L->contains(Switch->getDefaultDest()) && "Default case must not exit the loop!"
) ? static_cast<void> (0) : __assert_fail ("L->contains(Switch->getDefaultDest()) && \"Default case must not exit the loop!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7742, __PRETTY_FUNCTION__))
       "Default case must not exit the loop!")((L->contains(Switch->getDefaultDest()) && "Default case must not exit the loop!"
) ? static_cast<void> (0) : __assert_fail ("L->contains(Switch->getDefaultDest()) && \"Default case must not exit the loop!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7742, __PRETTY_FUNCTION__));
const SCEV *LHS = getSCEVAtScope(Switch->getCondition(), L);
const SCEV *RHS = getConstant(Switch->findCaseDest(ExitingBlock));

// while (X != Y) --> while (X-Y != 0)
ExitLimit EL = howFarToZero(getMinusSCEV(LHS, RHS), L, ControlsExit);
if (EL.hasAnyInfo())
  return EL;

return getCouldNotCompute();
7752}

7754static ConstantInt *
7755EvaluateConstantChrecAtConstant(const SCEVAddRecExpr *AddRec, ConstantInt *C,
                              ScalarEvolution &SE) {
const SCEV *InVal = SE.getConstant(C);
const SCEV *Val = AddRec->evaluateAtIteration(InVal, SE);
assert(isa<SCEVConstant>(Val) &&((isa<SCEVConstant>(Val) && "Evaluation of SCEV at constant didn't fold correctly?"
) ? static_cast<void> (0) : __assert_fail ("isa<SCEVConstant>(Val) && \"Evaluation of SCEV at constant didn't fold correctly?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7760, __PRETTY_FUNCTION__))
       "Evaluation of SCEV at constant didn't fold correctly?")((isa<SCEVConstant>(Val) && "Evaluation of SCEV at constant didn't fold correctly?"
) ? static_cast<void> (0) : __assert_fail ("isa<SCEVConstant>(Val) && \"Evaluation of SCEV at constant didn't fold correctly?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7760, __PRETTY_FUNCTION__));
return cast<SCEVConstant>(Val)->getValue();
7762}

7764/// Given an exit condition of 'icmp op load X, cst', try to see if we can
7765/// compute the backedge execution count.
7766ScalarEvolution::ExitLimit
7767ScalarEvolution::computeLoadConstantCompareExitLimit(
LoadInst *LI,
Constant *RHS,
const Loop *L,
ICmpInst::Predicate predicate) {
if (LI->isVolatile()) return getCouldNotCompute();

// Check to see if the loaded pointer is a getelementptr of a global.
// TODO: Use SCEV instead of manually grubbing with GEPs.
GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(LI->getOperand(0));
if (!GEP) return getCouldNotCompute();

// Make sure that it is really a constant global we are gepping, with an
// initializer, and make sure the first IDX is really 0.
GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer() ||
    GEP->getNumOperands() < 3 || !isa<Constant>(GEP->getOperand(1)) ||
    !cast<Constant>(GEP->getOperand(1))->isNullValue())
  return getCouldNotCompute();

// Okay, we allow one non-constant index into the GEP instruction.
Value *VarIdx = nullptr;
std::vector<Constant*> Indexes;
unsigned VarIdxNum = 0;
for (unsigned i = 2, e = GEP->getNumOperands(); i != e; ++i)
  if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(i))) {
    Indexes.push_back(CI);
  } else if (!isa<ConstantInt>(GEP->getOperand(i))) {
    if (VarIdx) return getCouldNotCompute();  // Multiple non-constant idx's.
    VarIdx = GEP->getOperand(i);
    VarIdxNum = i-2;
    Indexes.push_back(nullptr);
  }

// Loop-invariant loads may be a byproduct of loop optimization. Skip them.
if (!VarIdx)
  return getCouldNotCompute();

// Okay, we know we have a (load (gep GV, 0, X)) comparison with a constant.
// Check to see if X is a loop variant variable value now.
const SCEV *Idx = getSCEV(VarIdx);
Idx = getSCEVAtScope(Idx, L);

// We can only recognize very limited forms of loop index expressions, in
// particular, only affine AddRec's like {C1,+,C2}.
const SCEVAddRecExpr *IdxExpr = dyn_cast<SCEVAddRecExpr>(Idx);
if (!IdxExpr || !IdxExpr->isAffine() || isLoopInvariant(IdxExpr, L) ||
    !isa<SCEVConstant>(IdxExpr->getOperand(0)) ||
    !isa<SCEVConstant>(IdxExpr->getOperand(1)))
  return getCouldNotCompute();

unsigned MaxSteps = MaxBruteForceIterations;
for (unsigned IterationNum = 0; IterationNum != MaxSteps; ++IterationNum) {
  ConstantInt *ItCst = ConstantInt::get(
                         cast<IntegerType>(IdxExpr->getType()), IterationNum);
  ConstantInt *Val = EvaluateConstantChrecAtConstant(IdxExpr, ItCst, *this);

  // Form the GEP offset.
  Indexes[VarIdxNum] = Val;

  Constant *Result = ConstantFoldLoadThroughGEPIndices(GV->getInitializer(),
                                                       Indexes);
  if (!Result) break;  // Cannot compute!

  // Evaluate the condition for this iteration.
  Result = ConstantExpr::getICmp(predicate, Result, RHS);
  if (!isa<ConstantInt>(Result)) break;  // Couldn't decide for sure
  if (cast<ConstantInt>(Result)->getValue().isMinValue()) {
    ++NumArrayLenItCounts;
    return getConstant(ItCst);   // Found terminating iteration!
  }
}
return getCouldNotCompute();
7840}

7842ScalarEvolution::ExitLimit ScalarEvolution::computeShiftCompareExitLimit(
  Value *LHS, Value *RHSV, const Loop *L, ICmpInst::Predicate Pred) {
ConstantInt *RHS = dyn_cast<ConstantInt>(RHSV);
if (!RHS)
  return getCouldNotCompute();

const BasicBlock *Latch = L->getLoopLatch();
if (!Latch)
  return getCouldNotCompute();

const BasicBlock *Predecessor = L->getLoopPredecessor();
if (!Predecessor)
  return getCouldNotCompute();

// Return true if V is of the form "LHS `shift_op` <positive constant>".
// Return LHS in OutLHS and shift_opt in OutOpCode.
auto MatchPositiveShift =
    [](Value *V, Value *&OutLHS, Instruction::BinaryOps &OutOpCode) {

  using namespace PatternMatch;

  ConstantInt *ShiftAmt;
  if (match(V, m_LShr(m_Value(OutLHS), m_ConstantInt(ShiftAmt))))
    OutOpCode = Instruction::LShr;
  else if (match(V, m_AShr(m_Value(OutLHS), m_ConstantInt(ShiftAmt))))
    OutOpCode = Instruction::AShr;
  else if (match(V, m_Shl(m_Value(OutLHS), m_ConstantInt(ShiftAmt))))
    OutOpCode = Instruction::Shl;
  else
    return false;

  return ShiftAmt->getValue().isStrictlyPositive();
};

// Recognize a "shift recurrence" either of the form %iv or of %iv.shifted in
//
// loop:
//   %iv = phi i32 [ %iv.shifted, %loop ], [ %val, %preheader ]
//   %iv.shifted = lshr i32 %iv, <positive constant>
//
// Return true on a successful match.  Return the corresponding PHI node (%iv
// above) in PNOut and the opcode of the shift operation in OpCodeOut.
auto MatchShiftRecurrence =
    [&](Value *V, PHINode *&PNOut, Instruction::BinaryOps &OpCodeOut) {
  Optional<Instruction::BinaryOps> PostShiftOpCode;

  {
    Instruction::BinaryOps OpC;
    Value *V;

    // If we encounter a shift instruction, "peel off" the shift operation,
    // and remember that we did so.  Later when we inspect %iv's backedge
    // value, we will make sure that the backedge value uses the same
    // operation.
    //
    // Note: the peeled shift operation does not have to be the same
    // instruction as the one feeding into the PHI's backedge value.  We only
    // really care about it being the same *kind* of shift instruction --
    // that's all that is required for our later inferences to hold.
    if (MatchPositiveShift(LHS, V, OpC)) {
      PostShiftOpCode = OpC;
      LHS = V;
    }
  }

  PNOut = dyn_cast<PHINode>(LHS);
  if (!PNOut || PNOut->getParent() != L->getHeader())
    return false;

  Value *BEValue = PNOut->getIncomingValueForBlock(Latch);
  Value *OpLHS;

  return
      // The backedge value for the PHI node must be a shift by a positive
      // amount
      MatchPositiveShift(BEValue, OpLHS, OpCodeOut) &&

      // of the PHI node itself
      OpLHS == PNOut &&

      // and the kind of shift should be match the kind of shift we peeled
      // off, if any.
      (!PostShiftOpCode.hasValue() || *PostShiftOpCode == OpCodeOut);
};

PHINode *PN;
Instruction::BinaryOps OpCode;
if (!MatchShiftRecurrence(LHS, PN, OpCode))
  return getCouldNotCompute();

const DataLayout &DL = getDataLayout();

// The key rationale for this optimization is that for some kinds of shift
// recurrences, the value of the recurrence "stabilizes" to either 0 or -1
// within a finite number of iterations.  If the condition guarding the
// backedge (in the sense that the backedge is taken if the condition is true)
// is false for the value the shift recurrence stabilizes to, then we know
// that the backedge is taken only a finite number of times.

ConstantInt *StableValue = nullptr;
switch (OpCode) {
default:
  llvm_unreachable("Impossible case!")::llvm::llvm_unreachable_internal("Impossible case!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7944);

case Instruction::AShr: {
  // {K,ashr,<positive-constant>} stabilizes to signum(K) in at most
  // bitwidth(K) iterations.
  Value *FirstValue = PN->getIncomingValueForBlock(Predecessor);
  KnownBits Known = computeKnownBits(FirstValue, DL, 0, nullptr,
                                     Predecessor->getTerminator(), &DT);
  auto *Ty = cast<IntegerType>(RHS->getType());
  if (Known.isNonNegative())
    StableValue = ConstantInt::get(Ty, 0);
  else if (Known.isNegative())
    StableValue = ConstantInt::get(Ty, -1, true);
  else
    return getCouldNotCompute();

  break;
}
case Instruction::LShr:
case Instruction::Shl:
  // Both {K,lshr,<positive-constant>} and {K,shl,<positive-constant>}
  // stabilize to 0 in at most bitwidth(K) iterations.
  StableValue = ConstantInt::get(cast<IntegerType>(RHS->getType()), 0);
  break;
}

auto *Result =
    ConstantFoldCompareInstOperands(Pred, StableValue, RHS, DL, &TLI);
assert(Result->getType()->isIntegerTy(1) &&((Result->getType()->isIntegerTy(1) && "Otherwise cannot be an operand to a branch instruction"
) ? static_cast<void> (0) : __assert_fail ("Result->getType()->isIntegerTy(1) && \"Otherwise cannot be an operand to a branch instruction\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7973, __PRETTY_FUNCTION__))
       "Otherwise cannot be an operand to a branch instruction")((Result->getType()->isIntegerTy(1) && "Otherwise cannot be an operand to a branch instruction"
) ? static_cast<void> (0) : __assert_fail ("Result->getType()->isIntegerTy(1) && \"Otherwise cannot be an operand to a branch instruction\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 7973, __PRETTY_FUNCTION__));

if (Result->isZeroValue()) {
  unsigned BitWidth = getTypeSizeInBits(RHS->getType());
  const SCEV *UpperBound =
      getConstant(getEffectiveSCEVType(RHS->getType()), BitWidth);
  return ExitLimit(getCouldNotCompute(), UpperBound, false);
}

return getCouldNotCompute();
7983}

7985/// Return true if we can constant fold an instruction of the specified type,
7986/// assuming that all operands were constants.
7987static bool CanConstantFold(const Instruction *I) {
if (isa<BinaryOperator>(I) || isa<CmpInst>(I) ||
    isa<SelectInst>(I) || isa<CastInst>(I) || isa<GetElementPtrInst>(I) ||
    isa<LoadInst>(I) || isa<ExtractValueInst>(I))
  return true;

if (const CallInst *CI = dyn_cast<CallInst>(I))
  if (const Function *F = CI->getCalledFunction())
    return canConstantFoldCallTo(CI, F);
return false;
7997}

7999/// Determine whether this instruction can constant evolve within this loop
8000/// assuming its operands can all constant evolve.
8001static bool canConstantEvolve(Instruction *I, const Loop *L) {
// An instruction outside of the loop can't be derived from a loop PHI.
if (!L->contains(I)) return false;

if (isa<PHINode>(I)) {
  // We don't currently keep track of the control flow needed to evaluate
  // PHIs, so we cannot handle PHIs inside of loops.
  return L->getHeader() == I->getParent();
}

// If we won't be able to constant fold this expression even if the operands
// are constants, bail early.
return CanConstantFold(I);
8014}

8016/// getConstantEvolvingPHIOperands - Implement getConstantEvolvingPHI by
8017/// recursing through each instruction operand until reaching a loop header phi.
8018static PHINode *
8019getConstantEvolvingPHIOperands(Instruction *UseInst, const Loop *L,
                             DenseMap<Instruction *, PHINode *> &PHIMap,
                             unsigned Depth) {
if (Depth > MaxConstantEvolvingDepth)
  return nullptr;

// Otherwise, we can evaluate this instruction if all of its operands are
// constant or derived from a PHI node themselves.
PHINode *PHI = nullptr;
for (Value *Op : UseInst->operands()) {
  if (isa<Constant>(Op)) continue;

  Instruction *OpInst = dyn_cast<Instruction>(Op);
  if (!OpInst || !canConstantEvolve(OpInst, L)) return nullptr;

  PHINode *P = dyn_cast<PHINode>(OpInst);
  if (!P)
    // If this operand is already visited, reuse the prior result.
    // We may have P != PHI if this is the deepest point at which the
    // inconsistent paths meet.
    P = PHIMap.lookup(OpInst);
  if (!P) {
    // Recurse and memoize the results, whether a phi is found or not.
    // This recursive call invalidates pointers into PHIMap.
    P = getConstantEvolvingPHIOperands(OpInst, L, PHIMap, Depth + 1);
    PHIMap[OpInst] = P;
  }
  if (!P)
    return nullptr;  // Not evolving from PHI
  if (PHI && PHI != P)
    return nullptr;  // Evolving from multiple different PHIs.
  PHI = P;
}
// This is a expression evolving from a constant PHI!
return PHI;
8054}

8056/// getConstantEvolvingPHI - Given an LLVM value and a loop, return a PHI node
8057/// in the loop that V is derived from.  We allow arbitrary operations along the
8058/// way, but the operands of an operation must either be constants or a value
8059/// derived from a constant PHI.  If this expression does not fit with these
8060/// constraints, return null.
8061static PHINode *getConstantEvolvingPHI(Value *V, const Loop *L) {
Instruction *I = dyn_cast<Instruction>(V);
if (!I || !canConstantEvolve(I, L)) return nullptr;

if (PHINode *PN = dyn_cast<PHINode>(I))
  return PN;

// Record non-constant instructions contained by the loop.
DenseMap<Instruction *, PHINode *> PHIMap;
return getConstantEvolvingPHIOperands(I, L, PHIMap, 0);
8071}

8073/// EvaluateExpression - Given an expression that passes the
8074/// getConstantEvolvingPHI predicate, evaluate its value assuming the PHI node
8075/// in the loop has the value PHIVal.  If we can't fold this expression for some
8076/// reason, return null.
8077static Constant *EvaluateExpression(Value *V, const Loop *L,
                                  DenseMap<Instruction *, Constant *> &Vals,
                                  const DataLayout &DL,
                                  const TargetLibraryInfo *TLI) {
// Convenient constant check, but redundant for recursive calls.
if (Constant *C = dyn_cast<Constant>(V)) return C;
Instruction *I = dyn_cast<Instruction>(V);
if (!I) return nullptr;

if (Constant *C = Vals.lookup(I)) return C;

// An instruction inside the loop depends on a value outside the loop that we
// weren't given a mapping for, or a value such as a call inside the loop.
if (!canConstantEvolve(I, L)) return nullptr;

// An unmapped PHI can be due to a branch or another loop inside this loop,
// or due to this not being the initial iteration through a loop where we
// couldn't compute the evolution of this particular PHI last time.
if (isa<PHINode>(I)) return nullptr;

std::vector<Constant*> Operands(I->getNumOperands());

for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
  Instruction *Operand = dyn_cast<Instruction>(I->getOperand(i));
  if (!Operand) {
    Operands[i] = dyn_cast<Constant>(I->getOperand(i));
    if (!Operands[i]) return nullptr;
    continue;
  }
  Constant *C = EvaluateExpression(Operand, L, Vals, DL, TLI);
  Vals[Operand] = C;
  if (!C) return nullptr;
  Operands[i] = C;
}

if (CmpInst *CI = dyn_cast<CmpInst>(I))
  return ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0],
                                         Operands[1], DL, TLI);
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
  if (!LI->isVolatile())
    return ConstantFoldLoadFromConstPtr(Operands[0], LI->getType(), DL);
}
return ConstantFoldInstOperands(I, Operands, DL, TLI);
8120}


8123// If every incoming value to PN except the one for BB is a specific Constant,
8124// return that, else return nullptr.
8125static Constant *getOtherIncomingValue(PHINode *PN, BasicBlock *BB) {
Constant *IncomingVal = nullptr;

for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
  if (PN->getIncomingBlock(i) == BB)
    continue;

  auto *CurrentVal = dyn_cast<Constant>(PN->getIncomingValue(i));
  if (!CurrentVal)
    return nullptr;

  if (IncomingVal != CurrentVal) {
    if (IncomingVal)
      return nullptr;
    IncomingVal = CurrentVal;
  }
}

return IncomingVal;
8144}

8146/// getConstantEvolutionLoopExitValue - If we know that the specified Phi is
8147/// in the header of its containing loop, we know the loop executes a
8148/// constant number of times, and the PHI node is just a recurrence
8149/// involving constants, fold it.
8150Constant *
8151ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN,
                                                 const APInt &BEs,
                                                 const Loop *L) {
auto I = ConstantEvolutionLoopExitValue.find(PN);
if (I != ConstantEvolutionLoopExitValue.end())
  return I->second;

if (BEs.ugt(MaxBruteForceIterations))
  return ConstantEvolutionLoopExitValue[PN] = nullptr;  // Not going to evaluate it.

Constant *&RetVal = ConstantEvolutionLoopExitValue[PN];

DenseMap<Instruction *, Constant *> CurrentIterVals;
BasicBlock *Header = L->getHeader();
assert(PN->getParent() == Header && "Can't evaluate PHI not in loop header!")((PN->getParent() == Header && "Can't evaluate PHI not in loop header!"
) ? static_cast<void> (0) : __assert_fail ("PN->getParent() == Header && \"Can't evaluate PHI not in loop header!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8165, __PRETTY_FUNCTION__));

BasicBlock *Latch = L->getLoopLatch();
if (!Latch)
  return nullptr;

for (PHINode &PHI : Header->phis()) {
  if (auto *StartCST = getOtherIncomingValue(&PHI, Latch))
    CurrentIterVals[&PHI] = StartCST;
}
if (!CurrentIterVals.count(PN))
  return RetVal = nullptr;

Value *BEValue = PN->getIncomingValueForBlock(Latch);

// Execute the loop symbolically to determine the exit value.
assert(BEs.getActiveBits() < CHAR_BIT * sizeof(unsigned) &&((BEs.getActiveBits() < 8 * sizeof(unsigned) && "BEs is <= MaxBruteForceIterations which is an 'unsigned'!"
) ? static_cast<void> (0) : __assert_fail ("BEs.getActiveBits() < CHAR_BIT * sizeof(unsigned) && \"BEs is <= MaxBruteForceIterations which is an 'unsigned'!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8182, __PRETTY_FUNCTION__))
       "BEs is <= MaxBruteForceIterations which is an 'unsigned'!")((BEs.getActiveBits() < 8 * sizeof(unsigned) && "BEs is <= MaxBruteForceIterations which is an 'unsigned'!"
) ? static_cast<void> (0) : __assert_fail ("BEs.getActiveBits() < CHAR_BIT * sizeof(unsigned) && \"BEs is <= MaxBruteForceIterations which is an 'unsigned'!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8182, __PRETTY_FUNCTION__));

unsigned NumIterations = BEs.getZExtValue(); // must be in range
unsigned IterationNum = 0;
const DataLayout &DL = getDataLayout();
for (; ; ++IterationNum) {
  if (IterationNum == NumIterations)
    return RetVal = CurrentIterVals[PN];  // Got exit value!

  // Compute the value of the PHIs for the next iteration.
  // EvaluateExpression adds non-phi values to the CurrentIterVals map.
  DenseMap<Instruction *, Constant *> NextIterVals;
  Constant *NextPHI =
      EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI);
  if (!NextPHI)
    return nullptr;        // Couldn't evaluate!
  NextIterVals[PN] = NextPHI;

  bool StoppedEvolving = NextPHI == CurrentIterVals[PN];

  // Also evaluate the other PHI nodes.  However, we don't get to stop if we
  // cease to be able to evaluate one of them or if they stop evolving,
  // because that doesn't necessarily prevent us from computing PN.
  SmallVector<std::pair<PHINode *, Constant *>, 8> PHIsToCompute;
  for (const auto &I : CurrentIterVals) {
    PHINode *PHI = dyn_cast<PHINode>(I.first);
    if (!PHI || PHI == PN || PHI->getParent() != Header) continue;
    PHIsToCompute.emplace_back(PHI, I.second);
  }
  // We use two distinct loops because EvaluateExpression may invalidate any
  // iterators into CurrentIterVals.
  for (const auto &I : PHIsToCompute) {
    PHINode *PHI = I.first;
    Constant *&NextPHI = NextIterVals[PHI];
    if (!NextPHI) {   // Not already computed.
      Value *BEValue = PHI->getIncomingValueForBlock(Latch);
      NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI);
    }
    if (NextPHI != I.second)
      StoppedEvolving = false;
  }

  // If all entries in CurrentIterVals == NextIterVals then we can stop
  // iterating, the loop can't continue to change.
  if (StoppedEvolving)
    return RetVal = CurrentIterVals[PN];

  CurrentIterVals.swap(NextIterVals);
}
8231}

8233const SCEV *ScalarEvolution::computeExitCountExhaustively(const Loop *L,
                                                        Value *Cond,
                                                        bool ExitWhen) {
PHINode *PN = getConstantEvolvingPHI(Cond, L);
if (!PN) return getCouldNotCompute();

// If the loop is canonicalized, the PHI will have exactly two entries.
// That's the only form we support here.
if (PN->getNumIncomingValues() != 2) return getCouldNotCompute();

DenseMap<Instruction *, Constant *> CurrentIterVals;
BasicBlock *Header = L->getHeader();
assert(PN->getParent() == Header && "Can't evaluate PHI not in loop header!")((PN->getParent() == Header && "Can't evaluate PHI not in loop header!"
) ? static_cast<void> (0) : __assert_fail ("PN->getParent() == Header && \"Can't evaluate PHI not in loop header!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8245, __PRETTY_FUNCTION__));

BasicBlock *Latch = L->getLoopLatch();
assert(Latch && "Should follow from NumIncomingValues == 2!")((Latch && "Should follow from NumIncomingValues == 2!"
) ? static_cast<void> (0) : __assert_fail ("Latch && \"Should follow from NumIncomingValues == 2!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8248, __PRETTY_FUNCTION__));

for (PHINode &PHI : Header->phis()) {
  if (auto *StartCST = getOtherIncomingValue(&PHI, Latch))
    CurrentIterVals[&PHI] = StartCST;
}
if (!CurrentIterVals.count(PN))
  return getCouldNotCompute();

// Okay, we find a PHI node that defines the trip count of this loop.  Execute
// the loop symbolically to determine when the condition gets a value of
// "ExitWhen".
unsigned MaxIterations = MaxBruteForceIterations;   // Limit analysis.
const DataLayout &DL = getDataLayout();
for (unsigned IterationNum = 0; IterationNum != MaxIterations;++IterationNum){
  auto *CondVal = dyn_cast_or_null<ConstantInt>(
      EvaluateExpression(Cond, L, CurrentIterVals, DL, &TLI));

  // Couldn't symbolically evaluate.
  if (!CondVal) return getCouldNotCompute();

  if (CondVal->getValue() == uint64_t(ExitWhen)) {
    ++NumBruteForceTripCountsComputed;
    return getConstant(Type::getInt32Ty(getContext()), IterationNum);
  }

  // Update all the PHI nodes for the next iteration.
  DenseMap<Instruction *, Constant *> NextIterVals;

  // Create a list of which PHIs we need to compute. We want to do this before
  // calling EvaluateExpression on them because that may invalidate iterators
  // into CurrentIterVals.
  SmallVector<PHINode *, 8> PHIsToCompute;
  for (const auto &I : CurrentIterVals) {
    PHINode *PHI = dyn_cast<PHINode>(I.first);
    if (!PHI || PHI->getParent() != Header) continue;
    PHIsToCompute.push_back(PHI);
  }
  for (PHINode *PHI : PHIsToCompute) {
    Constant *&NextPHI = NextIterVals[PHI];
    if (NextPHI) continue;    // Already computed!

    Value *BEValue = PHI->getIncomingValueForBlock(Latch);
    NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL, &TLI);
  }
  CurrentIterVals.swap(NextIterVals);
}

// Too many iterations were needed to evaluate.
return getCouldNotCompute();
8298}

8300const SCEV *ScalarEvolution::getSCEVAtScope(const SCEV *V, const Loop *L) {
SmallVector<std::pair<const Loop *, const SCEV *>, 2> &Values =
    ValuesAtScopes[V];
// Check to see if we've folded this expression at this loop before.
for (auto &LS : Values)
  if (LS.first == L)
    return LS.second ? LS.second : V;

Values.emplace_back(L, nullptr);

// Otherwise compute it.
const SCEV *C = computeSCEVAtScope(V, L);
for (auto &LS : reverse(ValuesAtScopes[V]))
  if (LS.first == L) {
    LS.second = C;
    break;
  }
return C;
8318}

8320/// This builds up a Constant using the ConstantExpr interface.  That way, we
8321/// will return Constants for objects which aren't represented by a
8322/// SCEVConstant, because SCEVConstant is restricted to ConstantInt.
8323/// Returns NULL if the SCEV isn't representable as a Constant.
8324static Constant *BuildConstantFromSCEV(const SCEV *V) {
switch (V->getSCEVType()) {
case scCouldNotCompute:
case scAddRecExpr:
  return nullptr;
case scConstant:
  return cast<SCEVConstant>(V)->getValue();
case scUnknown:
  return dyn_cast<Constant>(cast<SCEVUnknown>(V)->getValue());
case scSignExtend: {
  const SCEVSignExtendExpr *SS = cast<SCEVSignExtendExpr>(V);
  if (Constant *CastOp = BuildConstantFromSCEV(SS->getOperand()))
    return ConstantExpr::getSExt(CastOp, SS->getType());
  return nullptr;
}
case scZeroExtend: {
  const SCEVZeroExtendExpr *SZ = cast<SCEVZeroExtendExpr>(V);
  if (Constant *CastOp = BuildConstantFromSCEV(SZ->getOperand()))
    return ConstantExpr::getZExt(CastOp, SZ->getType());
  return nullptr;
}
case scPtrToInt: {
  const SCEVPtrToIntExpr *P2I = cast<SCEVPtrToIntExpr>(V);
  if (Constant *CastOp = BuildConstantFromSCEV(P2I->getOperand()))
    return ConstantExpr::getPtrToInt(CastOp, P2I->getType());

  return nullptr;
}
case scTruncate: {
  const SCEVTruncateExpr *ST = cast<SCEVTruncateExpr>(V);
  if (Constant *CastOp = BuildConstantFromSCEV(ST->getOperand()))
    return ConstantExpr::getTrunc(CastOp, ST->getType());
  return nullptr;
}
case scAddExpr: {
  const SCEVAddExpr *SA = cast<SCEVAddExpr>(V);
  if (Constant *C = BuildConstantFromSCEV(SA->getOperand(0))) {
    if (PointerType *PTy = dyn_cast<PointerType>(C->getType())) {
      unsigned AS = PTy->getAddressSpace();
      Type *DestPtrTy = Type::getInt8PtrTy(C->getContext(), AS);
      C = ConstantExpr::getBitCast(C, DestPtrTy);
    }
    for (unsigned i = 1, e = SA->getNumOperands(); i != e; ++i) {
      Constant *C2 = BuildConstantFromSCEV(SA->getOperand(i));
      if (!C2)
        return nullptr;

      // First pointer!
      if (!C->getType()->isPointerTy() && C2->getType()->isPointerTy()) {
        unsigned AS = C2->getType()->getPointerAddressSpace();
        std::swap(C, C2);
        Type *DestPtrTy = Type::getInt8PtrTy(C->getContext(), AS);
        // The offsets have been converted to bytes.  We can add bytes to an
        // i8* by GEP with the byte count in the first index.
        C = ConstantExpr::getBitCast(C, DestPtrTy);
      }

      // Don't bother trying to sum two pointers. We probably can't
      // statically compute a load that results from it anyway.
      if (C2->getType()->isPointerTy())
        return nullptr;

      if (PointerType *PTy = dyn_cast<PointerType>(C->getType())) {
        if (PTy->getElementType()->isStructTy())
          C2 = ConstantExpr::getIntegerCast(
              C2, Type::getInt32Ty(C->getContext()), true);
        C = ConstantExpr::getGetElementPtr(PTy->getElementType(), C, C2);
      } else
        C = ConstantExpr::getAdd(C, C2);
    }
    return C;
  }
  return nullptr;
}
case scMulExpr: {
  const SCEVMulExpr *SM = cast<SCEVMulExpr>(V);
  if (Constant *C = BuildConstantFromSCEV(SM->getOperand(0))) {
    // Don't bother with pointers at all.
    if (C->getType()->isPointerTy())
      return nullptr;
    for (unsigned i = 1, e = SM->getNumOperands(); i != e; ++i) {
      Constant *C2 = BuildConstantFromSCEV(SM->getOperand(i));
      if (!C2 || C2->getType()->isPointerTy())
        return nullptr;
      C = ConstantExpr::getMul(C, C2);
    }
    return C;
  }
  return nullptr;
}
case scUDivExpr: {
  const SCEVUDivExpr *SU = cast<SCEVUDivExpr>(V);
  if (Constant *LHS = BuildConstantFromSCEV(SU->getLHS()))
    if (Constant *RHS = BuildConstantFromSCEV(SU->getRHS()))
      if (LHS->getType() == RHS->getType())
        return ConstantExpr::getUDiv(LHS, RHS);
  return nullptr;
}
case scSMaxExpr:
case scUMaxExpr:
case scSMinExpr:
case scUMinExpr:
  return nullptr; // TODO: smax, umax, smin, umax.
}
llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8428);
8429}

8431const SCEV *ScalarEvolution::computeSCEVAtScope(const SCEV *V, const Loop *L) {
if (isa<SCEVConstant>(V)) return V;

// If this instruction is evolved from a constant-evolving PHI, compute the
// exit value from the loop without using SCEVs.
if (const SCEVUnknown *SU = dyn_cast<SCEVUnknown>(V)) {
  if (Instruction *I = dyn_cast<Instruction>(SU->getValue())) {
    if (PHINode *PN = dyn_cast<PHINode>(I)) {
      const Loop *CurrLoop = this->LI[I->getParent()];
      // Looking for loop exit value.
      if (CurrLoop && CurrLoop->getParentLoop() == L &&
          PN->getParent() == CurrLoop->getHeader()) {
        // Okay, there is no closed form solution for the PHI node.  Check
        // to see if the loop that contains it has a known backedge-taken
        // count.  If so, we may be able to force computation of the exit
        // value.
        const SCEV *BackedgeTakenCount = getBackedgeTakenCount(CurrLoop);
        // This trivial case can show up in some degenerate cases where
        // the incoming IR has not yet been fully simplified.
        if (BackedgeTakenCount->isZero()) {
          Value *InitValue = nullptr;
          bool MultipleInitValues = false;
          for (unsigned i = 0; i < PN->getNumIncomingValues(); i++) {
            if (!CurrLoop->contains(PN->getIncomingBlock(i))) {
              if (!InitValue)
                InitValue = PN->getIncomingValue(i);
              else if (InitValue != PN->getIncomingValue(i)) {
                MultipleInitValues = true;
                break;
              }
            }
          }
          if (!MultipleInitValues && InitValue)
            return getSCEV(InitValue);
        }
        // Do we have a loop invariant value flowing around the backedge
        // for a loop which must execute the backedge?
        if (!isa<SCEVCouldNotCompute>(BackedgeTakenCount) &&
            isKnownPositive(BackedgeTakenCount) &&
            PN->getNumIncomingValues() == 2) {

          unsigned InLoopPred =
              CurrLoop->contains(PN->getIncomingBlock(0)) ? 0 : 1;
          Value *BackedgeVal = PN->getIncomingValue(InLoopPred);
          if (CurrLoop->isLoopInvariant(BackedgeVal))
            return getSCEV(BackedgeVal);
        }
        if (auto *BTCC = dyn_cast<SCEVConstant>(BackedgeTakenCount)) {
          // Okay, we know how many times the containing loop executes.  If
          // this is a constant evolving PHI node, get the final value at
          // the specified iteration number.
          Constant *RV = getConstantEvolutionLoopExitValue(
              PN, BTCC->getAPInt(), CurrLoop);
          if (RV) return getSCEV(RV);
        }
      }

      // If there is a single-input Phi, evaluate it at our scope. If we can
      // prove that this replacement does not break LCSSA form, use new value.
      if (PN->getNumOperands() == 1) {
        const SCEV *Input = getSCEV(PN->getOperand(0));
        const SCEV *InputAtScope = getSCEVAtScope(Input, L);
        // TODO: We can generalize it using LI.replacementPreservesLCSSAForm,
        // for the simplest case just support constants.
        if (isa<SCEVConstant>(InputAtScope)) return InputAtScope;
      }
    }

    // Okay, this is an expression that we cannot symbolically evaluate
    // into a SCEV.  Check to see if it's possible to symbolically evaluate
    // the arguments into constants, and if so, try to constant propagate the
    // result.  This is particularly useful for computing loop exit values.
    if (CanConstantFold(I)) {
      SmallVector<Constant *, 4> Operands;
      bool MadeImprovement = false;
      for (Value *Op : I->operands()) {
        if (Constant *C = dyn_cast<Constant>(Op)) {
          Operands.push_back(C);
          continue;
        }

        // If any of the operands is non-constant and if they are
        // non-integer and non-pointer, don't even try to analyze them
        // with scev techniques.
        if (!isSCEVable(Op->getType()))
          return V;

        const SCEV *OrigV = getSCEV(Op);
        const SCEV *OpV = getSCEVAtScope(OrigV, L);
        MadeImprovement |= OrigV != OpV;

        Constant *C = BuildConstantFromSCEV(OpV);
        if (!C) return V;
        if (C->getType() != Op->getType())
          C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
                                                            Op->getType(),
                                                            false),
                                    C, Op->getType());
        Operands.push_back(C);
      }

      // Check to see if getSCEVAtScope actually made an improvement.
      if (MadeImprovement) {
        Constant *C = nullptr;
        const DataLayout &DL = getDataLayout();
        if (const CmpInst *CI = dyn_cast<CmpInst>(I))
          C = ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0],
                                              Operands[1], DL, &TLI);
        else if (const LoadInst *Load = dyn_cast<LoadInst>(I)) {
          if (!Load->isVolatile())
            C = ConstantFoldLoadFromConstPtr(Operands[0], Load->getType(),
                                             DL);
        } else
          C = ConstantFoldInstOperands(I, Operands, DL, &TLI);
        if (!C) return V;
        return getSCEV(C);
      }
    }
  }

  // This is some other type of SCEVUnknown, just return it.
  return V;
}

if (const SCEVCommutativeExpr *Comm = dyn_cast<SCEVCommutativeExpr>(V)) {
  // Avoid performing the look-up in the common case where the specified
  // expression has no loop-variant portions.
  for (unsigned i = 0, e = Comm->getNumOperands(); i != e; ++i) {
    const SCEV *OpAtScope = getSCEVAtScope(Comm->getOperand(i), L);
    if (OpAtScope != Comm->getOperand(i)) {
      // Okay, at least one of these operands is loop variant but might be
      // foldable.  Build a new instance of the folded commutative expression.
      SmallVector<const SCEV *, 8> NewOps(Comm->op_begin(),
                                          Comm->op_begin()+i);
      NewOps.push_back(OpAtScope);

      for (++i; i != e; ++i) {
        OpAtScope = getSCEVAtScope(Comm->getOperand(i), L);
        NewOps.push_back(OpAtScope);
      }
      if (isa<SCEVAddExpr>(Comm))
        return getAddExpr(NewOps, Comm->getNoWrapFlags());
      if (isa<SCEVMulExpr>(Comm))
        return getMulExpr(NewOps, Comm->getNoWrapFlags());
      if (isa<SCEVMinMaxExpr>(Comm))
        return getMinMaxExpr(Comm->getSCEVType(), NewOps);
      llvm_unreachable("Unknown commutative SCEV type!")::llvm::llvm_unreachable_internal("Unknown commutative SCEV type!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8577);
    }
  }
  // If we got here, all operands are loop invariant.
  return Comm;
}

if (const SCEVUDivExpr *Div = dyn_cast<SCEVUDivExpr>(V)) {
  const SCEV *LHS = getSCEVAtScope(Div->getLHS(), L);
  const SCEV *RHS = getSCEVAtScope(Div->getRHS(), L);
  if (LHS == Div->getLHS() && RHS == Div->getRHS())
    return Div;   // must be loop invariant
  return getUDivExpr(LHS, RHS);
}

// If this is a loop recurrence for a loop that does not contain L, then we
// are dealing with the final value computed by the loop.
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V)) {
  // First, attempt to evaluate each operand.
  // Avoid performing the look-up in the common case where the specified
  // expression has no loop-variant portions.
  for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) {
    const SCEV *OpAtScope = getSCEVAtScope(AddRec->getOperand(i), L);
    if (OpAtScope == AddRec->getOperand(i))
      continue;

    // Okay, at least one of these operands is loop variant but might be
    // foldable.  Build a new instance of the folded commutative expression.
    SmallVector<const SCEV *, 8> NewOps(AddRec->op_begin(),
                                        AddRec->op_begin()+i);
    NewOps.push_back(OpAtScope);
    for (++i; i != e; ++i)
      NewOps.push_back(getSCEVAtScope(AddRec->getOperand(i), L));

    const SCEV *FoldedRec =
      getAddRecExpr(NewOps, AddRec->getLoop(),
                    AddRec->getNoWrapFlags(SCEV::FlagNW));
    AddRec = dyn_cast<SCEVAddRecExpr>(FoldedRec);
    // The addrec may be folded to a nonrecurrence, for example, if the
    // induction variable is multiplied by zero after constant folding. Go
    // ahead and return the folded value.
    if (!AddRec)
      return FoldedRec;
    break;
  }

  // If the scope is outside the addrec's loop, evaluate it by using the
  // loop exit value of the addrec.
  if (!AddRec->getLoop()->contains(L)) {
    // To evaluate this recurrence, we need to know how many times the AddRec
    // loop iterates.  Compute this now.
    const SCEV *BackedgeTakenCount = getBackedgeTakenCount(AddRec->getLoop());
    if (BackedgeTakenCount == getCouldNotCompute()) return AddRec;

    // Then, evaluate the AddRec.
    return AddRec->evaluateAtIteration(BackedgeTakenCount, *this);
  }

  return AddRec;
}

if (const SCEVZeroExtendExpr *Cast = dyn_cast<SCEVZeroExtendExpr>(V)) {
  const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L);
  if (Op == Cast->getOperand())
    return Cast;  // must be loop invariant
  return getZeroExtendExpr(Op, Cast->getType());
}

if (const SCEVSignExtendExpr *Cast = dyn_cast<SCEVSignExtendExpr>(V)) {
  const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L);
  if (Op == Cast->getOperand())
    return Cast;  // must be loop invariant
  return getSignExtendExpr(Op, Cast->getType());
}

if (const SCEVTruncateExpr *Cast = dyn_cast<SCEVTruncateExpr>(V)) {
  const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L);
  if (Op == Cast->getOperand())
    return Cast;  // must be loop invariant
  return getTruncateExpr(Op, Cast->getType());
}

if (const SCEVPtrToIntExpr *Cast = dyn_cast<SCEVPtrToIntExpr>(V)) {
  const SCEV *Op = getSCEVAtScope(Cast->getOperand(), L);
  if (Op == Cast->getOperand())
    return Cast; // must be loop invariant
  return getPtrToIntExpr(Op, Cast->getType());
}

llvm_unreachable("Unknown SCEV type!")::llvm::llvm_unreachable_internal("Unknown SCEV type!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8666);
8667}

8669const SCEV *ScalarEvolution::getSCEVAtScope(Value *V, const Loop *L) {
return getSCEVAtScope(getSCEV(V), L);
8671}

8673const SCEV *ScalarEvolution::stripInjectiveFunctions(const SCEV *S) const {
if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S))
  return stripInjectiveFunctions(ZExt->getOperand());
if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S))
  return stripInjectiveFunctions(SExt->getOperand());
return S;
8679}

8681/// Finds the minimum unsigned root of the following equation:
8682///
8683///     A * X = B (mod N)
8684///
8685/// where N = 2^BW and BW is the common bit width of A and B. The signedness of
8686/// A and B isn't important.
8687///
8688/// If the equation does not have a solution, SCEVCouldNotCompute is returned.
8689static const SCEV *SolveLinEquationWithOverflow(const APInt &A, const SCEV *B,
                                             ScalarEvolution &SE) {
uint32_t BW = A.getBitWidth();
assert(BW == SE.getTypeSizeInBits(B->getType()))((BW == SE.getTypeSizeInBits(B->getType())) ? static_cast<
void> (0) : __assert_fail ("BW == SE.getTypeSizeInBits(B->getType())"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8692, __PRETTY_FUNCTION__));
assert(A != 0 && "A must be non-zero.")((A != 0 && "A must be non-zero.") ? static_cast<void
> (0) : __assert_fail ("A != 0 && \"A must be non-zero.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8693, __PRETTY_FUNCTION__));

// 1. D = gcd(A, N)
//
// The gcd of A and N may have only one prime factor: 2. The number of
// trailing zeros in A is its multiplicity
uint32_t Mult2 = A.countTrailingZeros();
// D = 2^Mult2

// 2. Check if B is divisible by D.
//
// B is divisible by D if and only if the multiplicity of prime factor 2 for B
// is not less than multiplicity of this prime factor for D.
if (SE.GetMinTrailingZeros(B) < Mult2)
  return SE.getCouldNotCompute();

// 3. Compute I: the multiplicative inverse of (A / D) in arithmetic
// modulo (N / D).
//
// If D == 1, (N / D) == N == 2^BW, so we need one extra bit to represent
// (N / D) in general. The inverse itself always fits into BW bits, though,
// so we immediately truncate it.
APInt AD = A.lshr(Mult2).zext(BW + 1);  // AD = A / D
APInt Mod(BW + 1, 0);
Mod.setBit(BW - Mult2);  // Mod = N / D
APInt I = AD.multiplicativeInverse(Mod).trunc(BW);

// 4. Compute the minimum unsigned root of the equation:
// I * (B / D) mod (N / D)
// To simplify the computation, we factor out the divide by D:
// (I * B mod N) / D
const SCEV *D = SE.getConstant(APInt::getOneBitSet(BW, Mult2));
return SE.getUDivExactExpr(SE.getMulExpr(B, SE.getConstant(I)), D);
8726}

8728/// For a given quadratic addrec, generate coefficients of the corresponding
8729/// quadratic equation, multiplied by a common value to ensure that they are
8730/// integers.
8731/// The returned value is a tuple { A, B, C, M, BitWidth }, where
8732/// Ax^2 + Bx + C is the quadratic function, M is the value that A, B and C
8733/// were multiplied by, and BitWidth is the bit width of the original addrec
8734/// coefficients.
8735/// This function returns None if the addrec coefficients are not compile-
8736/// time constants.
8737static Optional<std::tuple<APInt, APInt, APInt, APInt, unsigned>>
8738GetQuadraticEquation(const SCEVAddRecExpr *AddRec) {
assert(AddRec->getNumOperands() == 3 && "This is not a quadratic chrec!")((AddRec->getNumOperands() == 3 && "This is not a quadratic chrec!"
) ? static_cast<void> (0) : __assert_fail ("AddRec->getNumOperands() == 3 && \"This is not a quadratic chrec!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8739, __PRETTY_FUNCTION__));
const SCEVConstant *LC = dyn_cast<SCEVConstant>(AddRec->getOperand(0));
const SCEVConstant *MC = dyn_cast<SCEVConstant>(AddRec->getOperand(1));
const SCEVConstant *NC = dyn_cast<SCEVConstant>(AddRec->getOperand(2));
LLVM_DEBUG(dbgs() << __func__ << ": analyzing quadratic addrec: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": analyzing quadratic addrec: "
 << *AddRec << '\n'; } } while (false)
                  << *AddRec << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": analyzing quadratic addrec: "
 << *AddRec << '\n'; } } while (false);

// We currently can only solve this if the coefficients are constants.
if (!LC || !MC || !NC) {
  LLVM_DEBUG(dbgs() << __func__ << ": coefficients are not constant\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": coefficients are not constant\n"
; } } while (false);
  return None;
}

APInt L = LC->getAPInt();
APInt M = MC->getAPInt();
APInt N = NC->getAPInt();
assert(!N.isNullValue() && "This is not a quadratic addrec")((!N.isNullValue() && "This is not a quadratic addrec"
) ? static_cast<void> (0) : __assert_fail ("!N.isNullValue() && \"This is not a quadratic addrec\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8755, __PRETTY_FUNCTION__));

unsigned BitWidth = LC->getAPInt().getBitWidth();
unsigned NewWidth = BitWidth + 1;
LLVM_DEBUG(dbgs() << __func__ << ": addrec coeff bw: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": addrec coeff bw: "
 << BitWidth << '\n'; } } while (false)
                  << BitWidth << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": addrec coeff bw: "
 << BitWidth << '\n'; } } while (false);
// The sign-extension (as opposed to a zero-extension) here matches the
// extension used in SolveQuadraticEquationWrap (with the same motivation).
N = N.sext(NewWidth);
M = M.sext(NewWidth);
L = L.sext(NewWidth);

// The increments are M, M+N, M+2N, ..., so the accumulated values are
//   L+M, (L+M)+(M+N), (L+M)+(M+N)+(M+2N), ..., that is,
//   L+M, L+2M+N, L+3M+3N, ...
// After n iterations the accumulated value Acc is L + nM + n(n-1)/2 N.
//
// The equation Acc = 0 is then
//   L + nM + n(n-1)/2 N = 0,  or  2L + 2M n + n(n-1) N = 0.
// In a quadratic form it becomes:
//   N n^2 + (2M-N) n + 2L = 0.

APInt A = N;
APInt B = 2 * M - A;
APInt C = 2 * L;
APInt T = APInt(NewWidth, 2);
LLVM_DEBUG(dbgs() << __func__ << ": equation " << A << "x^2 + " << Bdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": equation "
 << A << "x^2 + " << B << "x + " <<
 C << ", coeff bw: " << NewWidth << ", multiplied by "
 << T << '\n'; } } while (false)
                  << "x + " << C << ", coeff bw: " << NewWidthdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": equation "
 << A << "x^2 + " << B << "x + " <<
 C << ", coeff bw: " << NewWidth << ", multiplied by "
 << T << '\n'; } } while (false)
                  << ", multiplied by " << T << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": equation "
 << A << "x^2 + " << B << "x + " <<
 C << ", coeff bw: " << NewWidth << ", multiplied by "
 << T << '\n'; } } while (false);
return std::make_tuple(A, B, C, T, BitWidth);
8785}

8787/// Helper function to compare optional APInts:
8788/// (a) if X and Y both exist, return min(X, Y),
8789/// (b) if neither X nor Y exist, return None,
8790/// (c) if exactly one of X and Y exists, return that value.
8791static Optional<APInt> MinOptional(Optional<APInt> X, Optional<APInt> Y) {
if (X.hasValue() && Y.hasValue()) {
  unsigned W = std::max(X->getBitWidth(), Y->getBitWidth());
  APInt XW = X->sextOrSelf(W);
  APInt YW = Y->sextOrSelf(W);
  return XW.slt(YW) ? *X : *Y;
}
if (!X.hasValue() && !Y.hasValue())
  return None;
return X.hasValue() ? *X : *Y;
8801}

8803/// Helper function to truncate an optional APInt to a given BitWidth.
8804/// When solving addrec-related equations, it is preferable to return a value
8805/// that has the same bit width as the original addrec's coefficients. If the
8806/// solution fits in the original bit width, truncate it (except for i1).
8807/// Returning a value of a different bit width may inhibit some optimizations.
8808///
8809/// In general, a solution to a quadratic equation generated from an addrec
8810/// may require BW+1 bits, where BW is the bit width of the addrec's
8811/// coefficients. The reason is that the coefficients of the quadratic
8812/// equation are BW+1 bits wide (to avoid truncation when converting from
8813/// the addrec to the equation).
8814static Optional<APInt> TruncIfPossible(Optional<APInt> X, unsigned BitWidth) {
if (!X.hasValue())
  return None;
unsigned W = X->getBitWidth();
if (BitWidth > 1 && BitWidth < W && X->isIntN(BitWidth))
  return X->trunc(BitWidth);
return X;
8821}

8823/// Let c(n) be the value of the quadratic chrec {L,+,M,+,N} after n
8824/// iterations. The values L, M, N are assumed to be signed, and they
8825/// should all have the same bit widths.
8826/// Find the least n >= 0 such that c(n) = 0 in the arithmetic modulo 2^BW,
8827/// where BW is the bit width of the addrec's coefficients.
8828/// If the calculated value is a BW-bit integer (for BW > 1), it will be
8829/// returned as such, otherwise the bit width of the returned value may
8830/// be greater than BW.
8831///
8832/// This function returns None if
8833/// (a) the addrec coefficients are not constant, or
8834/// (b) SolveQuadraticEquationWrap was unable to find a solution. For cases
8835///     like x^2 = 5, no integer solutions exist, in other cases an integer
8836///     solution may exist, but SolveQuadraticEquationWrap may fail to find it.
8837static Optional<APInt>
8838SolveQuadraticAddRecExact(const SCEVAddRecExpr *AddRec, ScalarEvolution &SE) {
APInt A, B, C, M;
unsigned BitWidth;
auto T = GetQuadraticEquation(AddRec);
if (!T.hasValue())
  return None;

std::tie(A, B, C, M, BitWidth) = *T;
LLVM_DEBUG(dbgs() << __func__ << ": solving for unsigned overflow\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": solving for unsigned overflow\n"
; } } while (false);
Optional<APInt> X = APIntOps::SolveQuadraticEquationWrap(A, B, C, BitWidth+1);
if (!X.hasValue())
  return None;

ConstantInt *CX = ConstantInt::get(SE.getContext(), *X);
ConstantInt *V = EvaluateConstantChrecAtConstant(AddRec, CX, SE);
if (!V->isZero())
  return None;

return TruncIfPossible(X, BitWidth);
8857}

8859/// Let c(n) be the value of the quadratic chrec {0,+,M,+,N} after n
8860/// iterations. The values M, N are assumed to be signed, and they
8861/// should all have the same bit widths.
8862/// Find the least n such that c(n) does not belong to the given range,
8863/// while c(n-1) does.
8864///
8865/// This function returns None if
8866/// (a) the addrec coefficients are not constant, or
8867/// (b) SolveQuadraticEquationWrap was unable to find a solution for the
8868///     bounds of the range.
8869static Optional<APInt>
8870SolveQuadraticAddRecRange(const SCEVAddRecExpr *AddRec,
                        const ConstantRange &Range, ScalarEvolution &SE) {
assert(AddRec->getOperand(0)->isZero() &&((AddRec->getOperand(0)->isZero() && "Starting value of addrec should be 0"
) ? static_cast<void> (0) : __assert_fail ("AddRec->getOperand(0)->isZero() && \"Starting value of addrec should be 0\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8873, __PRETTY_FUNCTION__))
       "Starting value of addrec should be 0")((AddRec->getOperand(0)->isZero() && "Starting value of addrec should be 0"
) ? static_cast<void> (0) : __assert_fail ("AddRec->getOperand(0)->isZero() && \"Starting value of addrec should be 0\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8873, __PRETTY_FUNCTION__));
LLVM_DEBUG(dbgs() << __func__ << ": solving boundary crossing for range "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": solving boundary crossing for range "
 << Range << ", addrec " << *AddRec <<
 '\n'; } } while (false)
                  << Range << ", addrec " << *AddRec << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << __func__ << ": solving boundary crossing for range "
 << Range << ", addrec " << *AddRec <<
 '\n'; } } while (false);
// This case is handled in getNumIterationsInRange. Here we can assume that
// we start in the range.
assert(Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType()), 0)) &&((Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType
()), 0)) && "Addrec's initial value should be in range"
) ? static_cast<void> (0) : __assert_fail ("Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType()), 0)) && \"Addrec's initial value should be in range\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8879, __PRETTY_FUNCTION__))
       "Addrec's initial value should be in range")((Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType
()), 0)) && "Addrec's initial value should be in range"
) ? static_cast<void> (0) : __assert_fail ("Range.contains(APInt(SE.getTypeSizeInBits(AddRec->getType()), 0)) && \"Addrec's initial value should be in range\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 8879, __PRETTY_FUNCTION__));

APInt A, B, C, M;
unsigned BitWidth;
auto T = GetQuadraticEquation(AddRec);
if (!T.hasValue())
  return None;

// Be careful about the return value: there can be two reasons for not
// returning an actual number. First, if no solutions to the equations
// were found, and second, if the solutions don't leave the given range.
// The first case means that the actual solution is "unknown", the second
// means that it's known, but not valid. If the solution is unknown, we
// cannot make any conclusions.
// Return a pair: the optional solution and a flag indicating if the
// solution was found.
auto SolveForBoundary = [&](APInt Bound) -> std::pair<Optional<APInt>,bool> {
  // Solve for signed overflow and unsigned overflow, pick the lower
  // solution.
  LLVM_DEBUG(dbgs() << "SolveQuadraticAddRecRange: checking boundary "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: checking boundary "
 << Bound << " (before multiplying by " << M
 << ")\n"; } } while (false)
                    << Bound << " (before multiplying by " << M << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: checking boundary "
 << Bound << " (before multiplying by " << M
 << ")\n"; } } while (false);
  Bound *= M; // The quadratic equation multiplier.

  Optional<APInt> SO = None;
  if (BitWidth > 1) {
    LLVM_DEBUG(dbgs() << "SolveQuadraticAddRecRange: solving for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: solving for "
 "signed overflow\n"; } } while (false)
                         "signed overflow\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: solving for "
 "signed overflow\n"; } } while (false);
    SO = APIntOps::SolveQuadraticEquationWrap(A, B, -Bound, BitWidth);
  }
  LLVM_DEBUG(dbgs() << "SolveQuadraticAddRecRange: solving for "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: solving for "
 "unsigned overflow\n"; } } while (false)
                       "unsigned overflow\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { dbgs() << "SolveQuadraticAddRecRange: solving for "
 "unsigned overflow\n"; } } while (false);
  Optional<APInt> UO = APIntOps::SolveQuadraticEquationWrap(A, B, -Bound,
                                                            BitWidth+1);

  auto LeavesRange = [&] (const APInt &X) {
    ConstantInt *C0 = ConstantInt::get(SE.getContext(), X);
    ConstantInt *V0 = EvaluateConstantChrecAtConstant(AddRec, C0, SE);
    if (Range.contains(V0->getValue()))
      return false;
    // X should be at least 1, so X-1 is non-negative.
    ConstantInt *C1 = ConstantInt::get(SE.getContext(), X-1);
    ConstantInt *V1 = EvaluateConstantChrecAtConstant(AddRec, C1, SE);
    if (Range.contains(V1->getValue()))
      return true;
    return false;
  };

  // If SolveQuadraticEquationWrap returns None, it means that there can
  // be a solution, but the function failed to find it. We cannot treat it
  // as "no solution".
  if (!SO.hasValue() || !UO.hasValue())
    return { None, false };

  // Check the smaller value first to see if it leaves the range.
  // At this point, both SO and UO must have values.
  Optional<APInt> Min = MinOptional(SO, UO);
  if (LeavesRange(*Min))
    return { Min, true };
  Optional<APInt> Max = Min == SO ? UO : SO;
  if (LeavesRange(*Max))
    return { Max, true };

  // Solutions were found, but were eliminated, hence the "true".
  return { None, true };
};

std::tie(A, B, C, M, BitWidth) = *T;
// Lower bound is inclusive, subtract 1 to represent the exiting value.
APInt Lower = Range.getLower().sextOrSelf(A.getBitWidth()) - 1;
APInt Upper = Range.getUpper().sextOrSelf(A.getBitWidth());
auto SL = SolveForBoundary(Lower);
auto SU = SolveForBoundary(Upper);
// If any of the solutions was unknown, no meaninigful conclusions can
// be made.
if (!SL.second || !SU.second)
  return None;

// Claim: The correct solution is not some value between Min and Max.
//
// Justification: Assuming that Min and Max are different values, one of
// them is when the first signed overflow happens, the other is when the
// first unsigned overflow happens. Crossing the range boundary is only
// possible via an overflow (treating 0 as a special case of it, modeling
// an overflow as crossing k*2^W for some k).
//
// The interesting case here is when Min was eliminated as an invalid
// solution, but Max was not. The argument is that if there was another
// overflow between Min and Max, it would also have been eliminated if
// it was considered.
//
// For a given boundary, it is possible to have two overflows of the same
// type (signed/unsigned) without having the other type in between: this
// can happen when the vertex of the parabola is between the iterations
// corresponding to the overflows. This is only possible when the two
// overflows cross k*2^W for the same k. In such case, if the second one
// left the range (and was the first one to do so), the first overflow
// would have to enter the range, which would mean that either we had left
// the range before or that we started outside of it. Both of these cases
// are contradictions.
//
// Claim: In the case where SolveForBoundary returns None, the correct
// solution is not some value between the Max for this boundary and the
// Min of the other boundary.
//
// Justification: Assume that we had such Max_A and Min_B corresponding
// to range boundaries A and B and such that Max_A < Min_B. If there was
// a solution between Max_A and Min_B, it would have to be caused by an
// overflow corresponding to either A or B. It cannot correspond to B,
// since Min_B is the first occurrence of such an overflow. If it
// corresponded to A, it would have to be either a signed or an unsigned
// overflow that is larger than both eliminated overflows for A. But
// between the eliminated overflows and this overflow, the values would
// cover the entire value space, thus crossing the other boundary, which
// is a contradiction.

return TruncIfPossible(MinOptional(SL.first, SU.first), BitWidth);
8995}

8997ScalarEvolution::ExitLimit
8998ScalarEvolution::howFarToZero(const SCEV *V, const Loop *L, bool ControlsExit,
                            bool AllowPredicates) {

// This is only used for loops with a "x != y" exit test. The exit condition
// is now expressed as a single expression, V = x-y. So the exit test is
// effectively V != 0.  We know and take advantage of the fact that this
// expression only being used in a comparison by zero context.

SmallPtrSet<const SCEVPredicate *, 4> Predicates;
// If the value is a constant
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
  // If the value is already zero, the branch will execute zero times.
  if (C->getValue()->isZero()) return C;
  return getCouldNotCompute();  // Otherwise it will loop infinitely.
}

const SCEVAddRecExpr *AddRec =
    dyn_cast<SCEVAddRecExpr>(stripInjectiveFunctions(V));

if (!AddRec && AllowPredicates)
  // Try to make this an AddRec using runtime tests, in the first X
  // iterations of this loop, where X is the SCEV expression found by the
  // algorithm below.
  AddRec = convertSCEVToAddRecWithPredicates(V, L, Predicates);

if (!AddRec || AddRec->getLoop() != L)
  return getCouldNotCompute();

// If this is a quadratic (3-term) AddRec {L,+,M,+,N}, find the roots of
// the quadratic equation to solve it.
if (AddRec->isQuadratic() && AddRec->getType()->isIntegerTy()) {
  // We can only use this value if the chrec ends up with an exact zero
  // value at this index.  When solving for "X*X != 5", for example, we
  // should not accept a root of 2.
  if (auto S = SolveQuadraticAddRecExact(AddRec, *this)) {
    const auto *R = cast<SCEVConstant>(getConstant(S.getValue()));
    return ExitLimit(R, R, false, Predicates);
  }
  return getCouldNotCompute();
}

// Otherwise we can only handle this if it is affine.
if (!AddRec->isAffine())
  return getCouldNotCompute();

// If this is an affine expression, the execution count of this branch is
// the minimum unsigned root of the following equation:
//
//     Start + Step*N = 0 (mod 2^BW)
//
// equivalent to:
//
//             Step*N = -Start (mod 2^BW)
//
// where BW is the common bit width of Start and Step.

// Get the initial value for the loop.
const SCEV *Start = getSCEVAtScope(AddRec->getStart(), L->getParentLoop());
const SCEV *Step = getSCEVAtScope(AddRec->getOperand(1), L->getParentLoop());

// For now we handle only constant steps.
//
// TODO: Handle a nonconstant Step given AddRec<NUW>. If the
// AddRec is NUW, then (in an unsigned sense) it cannot be counting up to wrap
// to 0, it must be counting down to equal 0. Consequently, N = Start / -Step.
// We have not yet seen any such cases.
const SCEVConstant *StepC = dyn_cast<SCEVConstant>(Step);
if (!StepC || StepC->getValue()->isZero())
  return getCouldNotCompute();

// For positive steps (counting up until unsigned overflow):
//   N = -Start/Step (as unsigned)
// For negative steps (counting down to zero):
//   N = Start/-Step
// First compute the unsigned distance from zero in the direction of Step.
bool CountDown = StepC->getAPInt().isNegative();
const SCEV *Distance = CountDown ? Start : getNegativeSCEV(Start);

// Handle unitary steps, which cannot wraparound.
// 1*N = -Start; -1*N = Start (mod 2^BW), so:
//   N = Distance (as unsigned)
if (StepC->getValue()->isOne() || StepC->getValue()->isMinusOne()) {
  APInt MaxBECount = getUnsignedRangeMax(applyLoopGuards(Distance, L));
  APInt MaxBECountBase = getUnsignedRangeMax(Distance);
  if (MaxBECountBase.ult(MaxBECount))
    MaxBECount = MaxBECountBase;

  // When a loop like "for (int i = 0; i != n; ++i) { /* body */ }" is rotated,
  // we end up with a loop whose backedge-taken count is n - 1.  Detect this
  // case, and see if we can improve the bound.
  //
  // Explicitly handling this here is necessary because getUnsignedRange
  // isn't context-sensitive; it doesn't know that we only care about the
  // range inside the loop.
  const SCEV *Zero = getZero(Distance->getType());
  const SCEV *One = getOne(Distance->getType());
  const SCEV *DistancePlusOne = getAddExpr(Distance, One);
  if (isLoopEntryGuardedByCond(L, ICmpInst::ICMP_NE, DistancePlusOne, Zero)) {
    // If Distance + 1 doesn't overflow, we can compute the maximum distance
    // as "unsigned_max(Distance + 1) - 1".
    ConstantRange CR = getUnsignedRange(DistancePlusOne);
    MaxBECount = APIntOps::umin(MaxBECount, CR.getUnsignedMax() - 1);
  }
  return ExitLimit(Distance, getConstant(MaxBECount), false, Predicates);
}

// If the condition controls loop exit (the loop exits only if the expression
// is true) and the addition is no-wrap we can use unsigned divide to
// compute the backedge count.  In this case, the step may not divide the
// distance, but we don't care because if the condition is "missed" the loop
// will have undefined behavior due to wrapping.
if (ControlsExit && AddRec->hasNoSelfWrap() &&
    loopHasNoAbnormalExits(AddRec->getLoop())) {
  const SCEV *Exact =
      getUDivExpr(Distance, CountDown ? getNegativeSCEV(Step) : Step);
  const SCEV *Max =
      Exact == getCouldNotCompute()
          ? Exact
          : getConstant(getUnsignedRangeMax(Exact));
  return ExitLimit(Exact, Max, false, Predicates);
}

// Solve the general equation.
const SCEV *E = SolveLinEquationWithOverflow(StepC->getAPInt(),
                                             getNegativeSCEV(Start), *this);
const SCEV *M = E == getCouldNotCompute()
                    ? E
                    : getConstant(getUnsignedRangeMax(E));
return ExitLimit(E, M, false, Predicates);
9127}

9129ScalarEvolution::ExitLimit
9130ScalarEvolution::howFarToNonZero(const SCEV *V, const Loop *L) {
// Loops that look like: while (X == 0) are very strange indeed.  We don't
// handle them yet except for the trivial case.  This could be expanded in the
// future as needed.

// If the value is a constant, check to see if it is known to be non-zero
// already.  If so, the backedge will execute zero times.
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(V)) {
  if (!C->getValue()->isZero())
    return getZero(C->getType());
  return getCouldNotCompute();  // Otherwise it will loop infinitely.
}

// We could implement others, but I really doubt anyone writes loops like
// this, and if they did, they would already be constant folded.
return getCouldNotCompute();
9146}

9148std::pair<const BasicBlock *, const BasicBlock *>
9149ScalarEvolution::getPredecessorWithUniqueSuccessorForBB(const BasicBlock *BB)
  const {
// If the block has a unique predecessor, then there is no path from the
// predecessor to the block that does not go through the direct edge
// from the predecessor to the block.
if (const BasicBlock *Pred = BB->getSinglePredecessor())
  return {Pred, BB};

// A loop's header is defined to be a block that dominates the loop.
// If the header has a unique predecessor outside the loop, it must be
// a block that has exactly one successor that can reach the loop.
if (const Loop *L = LI.getLoopFor(BB))
  return {L->getLoopPredecessor(), L->getHeader()};

return {nullptr, nullptr};
9164}

9166/// SCEV structural equivalence is usually sufficient for testing whether two
9167/// expressions are equal, however for the purposes of looking for a condition
9168/// guarding a loop, it can be useful to be a little more general, since a
9169/// front-end may have replicated the controlling expression.
9170static bool HasSameValue(const SCEV *A, const SCEV *B) {
// Quick check to see if they are the same SCEV.
if (A == B) return true;

auto ComputesEqualValues = [](const Instruction *A, const Instruction *B) {
  // Not all instructions that are "identical" compute the same value.  For
  // instance, two distinct alloca instructions allocating the same type are
  // identical and do not read memory; but compute distinct values.
  return A->isIdenticalTo(B) && (isa<BinaryOperator>(A) || isa<GetElementPtrInst>(A));
};

// Otherwise, if they're both SCEVUnknown, it's possible that they hold
// two different instructions with the same value. Check for this case.
if (const SCEVUnknown *AU = dyn_cast<SCEVUnknown>(A))
  if (const SCEVUnknown *BU = dyn_cast<SCEVUnknown>(B))
    if (const Instruction *AI = dyn_cast<Instruction>(AU->getValue()))
      if (const Instruction *BI = dyn_cast<Instruction>(BU->getValue()))
        if (ComputesEqualValues(AI, BI))
          return true;

// Otherwise assume they may have a different value.
return false;
9192}

9194bool ScalarEvolution::SimplifyICmpOperands(ICmpInst::Predicate &Pred,
                                         const SCEV *&LHS, const SCEV *&RHS,
                                         unsigned Depth) {
bool Changed = false;
// Simplifies ICMP to trivial true or false by turning it into '0 == 0' or
// '0 != 0'.
auto TrivialCase = [&](bool TriviallyTrue) {
  LHS = RHS = getConstant(ConstantInt::getFalse(getContext()));
  Pred = TriviallyTrue ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE;
  return true;
};
// If we hit the max recursion limit bail out.
if (Depth >= 3)
  return false;

// Canonicalize a constant to the right side.
if (const SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
  // Check for both operands constant.
  if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
    if (ConstantExpr::getICmp(Pred,
                              LHSC->getValue(),
                              RHSC->getValue())->isNullValue())
      return TrivialCase(false);
    else
      return TrivialCase(true);
  }
  // Otherwise swap the operands to put the constant on the right.
  std::swap(LHS, RHS);
  Pred = ICmpInst::getSwappedPredicate(Pred);
  Changed = true;
}

// If we're comparing an addrec with a value which is loop-invariant in the
// addrec's loop, put the addrec on the left. Also make a dominance check,
// as both operands could be addrecs loop-invariant in each other's loop.
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(RHS)) {
  const Loop *L = AR->getLoop();
  if (isLoopInvariant(LHS, L) && properlyDominates(LHS, L->getHeader())) {
    std::swap(LHS, RHS);
    Pred = ICmpInst::getSwappedPredicate(Pred);
    Changed = true;
  }
}

// If there's a constant operand, canonicalize comparisons with boundary
// cases, and canonicalize *-or-equal comparisons to regular comparisons.
if (const SCEVConstant *RC = dyn_cast<SCEVConstant>(RHS)) {
  const APInt &RA = RC->getAPInt();

  bool SimplifiedByConstantRange = false;

  if (!ICmpInst::isEquality(Pred)) {
    ConstantRange ExactCR = ConstantRange::makeExactICmpRegion(Pred, RA);
    if (ExactCR.isFullSet())
      return TrivialCase(true);
    else if (ExactCR.isEmptySet())
      return TrivialCase(false);

    APInt NewRHS;
    CmpInst::Predicate NewPred;
    if (ExactCR.getEquivalentICmp(NewPred, NewRHS) &&
        ICmpInst::isEquality(NewPred)) {
      // We were able to convert an inequality to an equality.
      Pred = NewPred;
      RHS = getConstant(NewRHS);
      Changed = SimplifiedByConstantRange = true;
    }
  }

  if (!SimplifiedByConstantRange) {
    switch (Pred) {
    default:
      break;
    case ICmpInst::ICMP_EQ:
    case ICmpInst::ICMP_NE:
      // Fold ((-1) * %a) + %b == 0 (equivalent to %b-%a == 0) into %a == %b.
      if (!RA)
        if (const SCEVAddExpr *AE = dyn_cast<SCEVAddExpr>(LHS))
          if (const SCEVMulExpr *ME =
                  dyn_cast<SCEVMulExpr>(AE->getOperand(0)))
            if (AE->getNumOperands() == 2 && ME->getNumOperands() == 2 &&
                ME->getOperand(0)->isAllOnesValue()) {
              RHS = AE->getOperand(1);
              LHS = ME->getOperand(1);
              Changed = true;
            }
      break;


      // The "Should have been caught earlier!" messages refer to the fact
      // that the ExactCR.isFullSet() or ExactCR.isEmptySet() check above
      // should have fired on the corresponding cases, and canonicalized the
      // check to trivial case.

    case ICmpInst::ICMP_UGE:
      assert(!RA.isMinValue() && "Should have been caught earlier!")((!RA.isMinValue() && "Should have been caught earlier!"
) ? static_cast<void> (0) : __assert_fail ("!RA.isMinValue() && \"Should have been caught earlier!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9289, __PRETTY_FUNCTION__));
      Pred = ICmpInst::ICMP_UGT;
      RHS = getConstant(RA - 1);
      Changed = true;
      break;
    case ICmpInst::ICMP_ULE:
      assert(!RA.isMaxValue() && "Should have been caught earlier!")((!RA.isMaxValue() && "Should have been caught earlier!"
) ? static_cast<void> (0) : __assert_fail ("!RA.isMaxValue() && \"Should have been caught earlier!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9295, __PRETTY_FUNCTION__));
      Pred = ICmpInst::ICMP_ULT;
      RHS = getConstant(RA + 1);
      Changed = true;
      break;
    case ICmpInst::ICMP_SGE:
      assert(!RA.isMinSignedValue() && "Should have been caught earlier!")((!RA.isMinSignedValue() && "Should have been caught earlier!"
) ? static_cast<void> (0) : __assert_fail ("!RA.isMinSignedValue() && \"Should have been caught earlier!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9301, __PRETTY_FUNCTION__));
      Pred = ICmpInst::ICMP_SGT;
      RHS = getConstant(RA - 1);
      Changed = true;
      break;
    case ICmpInst::ICMP_SLE:
      assert(!RA.isMaxSignedValue() && "Should have been caught earlier!")((!RA.isMaxSignedValue() && "Should have been caught earlier!"
) ? static_cast<void> (0) : __assert_fail ("!RA.isMaxSignedValue() && \"Should have been caught earlier!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9307, __PRETTY_FUNCTION__));
      Pred = ICmpInst::ICMP_SLT;
      RHS = getConstant(RA + 1);
      Changed = true;
      break;
    }
  }
}

// Check for obvious equality.
if (HasSameValue(LHS, RHS)) {
  if (ICmpInst::isTrueWhenEqual(Pred))
    return TrivialCase(true);
  if (ICmpInst::isFalseWhenEqual(Pred))
    return TrivialCase(false);
}

// If possible, canonicalize GE/LE comparisons to GT/LT comparisons, by
// adding or subtracting 1 from one of the operands.
switch (Pred) {
case ICmpInst::ICMP_SLE:
  if (!getSignedRangeMax(RHS).isMaxSignedValue()) {
    RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS,
                     SCEV::FlagNSW);
    Pred = ICmpInst::ICMP_SLT;
    Changed = true;
  } else if (!getSignedRangeMin(LHS).isMinSignedValue()) {
    LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS,
                     SCEV::FlagNSW);
    Pred = ICmpInst::ICMP_SLT;
    Changed = true;
  }
  break;
case ICmpInst::ICMP_SGE:
  if (!getSignedRangeMin(RHS).isMinSignedValue()) {
    RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS,
                     SCEV::FlagNSW);
    Pred = ICmpInst::ICMP_SGT;
    Changed = true;
  } else if (!getSignedRangeMax(LHS).isMaxSignedValue()) {
    LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS,
                     SCEV::FlagNSW);
    Pred = ICmpInst::ICMP_SGT;
    Changed = true;
  }
  break;
case ICmpInst::ICMP_ULE:
  if (!getUnsignedRangeMax(RHS).isMaxValue()) {
    RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS,
                     SCEV::FlagNUW);
    Pred = ICmpInst::ICMP_ULT;
    Changed = true;
  } else if (!getUnsignedRangeMin(LHS).isMinValue()) {
    LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS);
    Pred = ICmpInst::ICMP_ULT;
    Changed = true;
  }
  break;
case ICmpInst::ICMP_UGE:
  if (!getUnsignedRangeMin(RHS).isMinValue()) {
    RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS);
    Pred = ICmpInst::ICMP_UGT;
    Changed = true;
  } else if (!getUnsignedRangeMax(LHS).isMaxValue()) {
    LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS,
                     SCEV::FlagNUW);
    Pred = ICmpInst::ICMP_UGT;
    Changed = true;
  }
  break;
default:
  break;
}

// TODO: More simplifications are possible here.

// Recursively simplify until we either hit a recursion limit or nothing
// changes.
if (Changed)
  return SimplifyICmpOperands(Pred, LHS, RHS, Depth+1);

return Changed;
9389}

9391bool ScalarEvolution::isKnownNegative(const SCEV *S) {
return getSignedRangeMax(S).isNegative();
9393}

9395bool ScalarEvolution::isKnownPositive(const SCEV *S) {
return getSignedRangeMin(S).isStrictlyPositive();
9397}

9399bool ScalarEvolution::isKnownNonNegative(const SCEV *S) {
return !getSignedRangeMin(S).isNegative();
9401}

9403bool ScalarEvolution::isKnownNonPositive(const SCEV *S) {
return !getSignedRangeMax(S).isStrictlyPositive();
9405}

9407bool ScalarEvolution::isKnownNonZero(const SCEV *S) {
return isKnownNegative(S) || isKnownPositive(S);
9409}

9411std::pair<const SCEV *, const SCEV *>
9412ScalarEvolution::SplitIntoInitAndPostInc(const Loop *L, const SCEV *S) {
// Compute SCEV on entry of loop L.
const SCEV *Start = SCEVInitRewriter::rewrite(S, L, *this);
if (Start == getCouldNotCompute())
  return { Start, Start };
// Compute post increment SCEV for loop L.
const SCEV *PostInc = SCEVPostIncRewriter::rewrite(S, L, *this);
assert(PostInc != getCouldNotCompute() && "Unexpected could not compute")((PostInc != getCouldNotCompute() && "Unexpected could not compute"
) ? static_cast<void> (0) : __assert_fail ("PostInc != getCouldNotCompute() && \"Unexpected could not compute\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9419, __PRETTY_FUNCTION__));
return { Start, PostInc };
9421}

9423bool ScalarEvolution::isKnownViaInduction(ICmpInst::Predicate Pred,
                                        const SCEV *LHS, const SCEV *RHS) {
// First collect all loops.
SmallPtrSet<const Loop *, 8> LoopsUsed;
getUsedLoops(LHS, LoopsUsed);
getUsedLoops(RHS, LoopsUsed);

if (LoopsUsed.empty())
  return false;

// Domination relationship must be a linear order on collected loops.
9434#ifndef NDEBUG
for (auto *L1 : LoopsUsed)
  for (auto *L2 : LoopsUsed)
    assert((DT.dominates(L1->getHeader(), L2->getHeader()) ||(((DT.dominates(L1->getHeader(), L2->getHeader()) || DT
.dominates(L2->getHeader(), L1->getHeader())) &&
 "Domination relationship is not a linear order") ? static_cast
<void> (0) : __assert_fail ("(DT.dominates(L1->getHeader(), L2->getHeader()) || DT.dominates(L2->getHeader(), L1->getHeader())) && \"Domination relationship is not a linear order\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9439, __PRETTY_FUNCTION__))
            DT.dominates(L2->getHeader(), L1->getHeader())) &&(((DT.dominates(L1->getHeader(), L2->getHeader()) || DT
.dominates(L2->getHeader(), L1->getHeader())) &&
 "Domination relationship is not a linear order") ? static_cast
<void> (0) : __assert_fail ("(DT.dominates(L1->getHeader(), L2->getHeader()) || DT.dominates(L2->getHeader(), L1->getHeader())) && \"Domination relationship is not a linear order\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9439, __PRETTY_FUNCTION__))
           "Domination relationship is not a linear order")(((DT.dominates(L1->getHeader(), L2->getHeader()) || DT
.dominates(L2->getHeader(), L1->getHeader())) &&
 "Domination relationship is not a linear order") ? static_cast
<void> (0) : __assert_fail ("(DT.dominates(L1->getHeader(), L2->getHeader()) || DT.dominates(L2->getHeader(), L1->getHeader())) && \"Domination relationship is not a linear order\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9439, __PRETTY_FUNCTION__));
9440#endif

const Loop *MDL =
    *std::max_element(LoopsUsed.begin(), LoopsUsed.end(),
                      [&](const Loop *L1, const Loop *L2) {
       return DT.properlyDominates(L1->getHeader(), L2->getHeader());
     });

// Get init and post increment value for LHS.
auto SplitLHS = SplitIntoInitAndPostInc(MDL, LHS);
// if LHS contains unknown non-invariant SCEV then bail out.
if (SplitLHS.first == getCouldNotCompute())
  return false;
assert (SplitLHS.second != getCouldNotCompute() && "Unexpected CNC")((SplitLHS.second != getCouldNotCompute() && "Unexpected CNC"
) ? static_cast<void> (0) : __assert_fail ("SplitLHS.second != getCouldNotCompute() && \"Unexpected CNC\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9453, __PRETTY_FUNCTION__));
// Get init and post increment value for RHS.
auto SplitRHS = SplitIntoInitAndPostInc(MDL, RHS);
// if RHS contains unknown non-invariant SCEV then bail out.
if (SplitRHS.first == getCouldNotCompute())
  return false;
assert (SplitRHS.second != getCouldNotCompute() && "Unexpected CNC")((SplitRHS.second != getCouldNotCompute() && "Unexpected CNC"
) ? static_cast<void> (0) : __assert_fail ("SplitRHS.second != getCouldNotCompute() && \"Unexpected CNC\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9459, __PRETTY_FUNCTION__));
// It is possible that init SCEV contains an invariant load but it does
// not dominate MDL and is not available at MDL loop entry, so we should
// check it here.
if (!isAvailableAtLoopEntry(SplitLHS.first, MDL) ||
    !isAvailableAtLoopEntry(SplitRHS.first, MDL))
  return false;

// It seems backedge guard check is faster than entry one so in some cases
// it can speed up whole estimation by short circuit
return isLoopBackedgeGuardedByCond(MDL, Pred, SplitLHS.second,
                                   SplitRHS.second) &&
       isLoopEntryGuardedByCond(MDL, Pred, SplitLHS.first, SplitRHS.first);
9472}

9474bool ScalarEvolution::isKnownPredicate(ICmpInst::Predicate Pred,
                                     const SCEV *LHS, const SCEV *RHS) {
// Canonicalize the inputs first.
(void)SimplifyICmpOperands(Pred, LHS, RHS);

if (isKnownViaInduction(Pred, LHS, RHS))
  return true;

if (isKnownPredicateViaSplitting(Pred, LHS, RHS))
  return true;

// Otherwise see what can be done with some simple reasoning.
return isKnownViaNonRecursiveReasoning(Pred, LHS, RHS);
9487}

9489bool ScalarEvolution::isKnownPredicateAt(ICmpInst::Predicate Pred,
                                       const SCEV *LHS, const SCEV *RHS,
                                       const Instruction *Context) {
// TODO: Analyze guards and assumes from Context's block.
return isKnownPredicate(Pred, LHS, RHS) ||
54
←
Assuming the condition is false→
       isBasicBlockEntryGuardedByCond(Context->getParent(), Pred, LHS, RHS);
55
←
Called C++ object pointer is null
9495}

9497bool ScalarEvolution::isKnownOnEveryIteration(ICmpInst::Predicate Pred,
                                            const SCEVAddRecExpr *LHS,
                                            const SCEV *RHS) {
const Loop *L = LHS->getLoop();
return isLoopEntryGuardedByCond(L, Pred, LHS->getStart(), RHS) &&
       isLoopBackedgeGuardedByCond(L, Pred, LHS->getPostIncExpr(*this), RHS);
9503}

9505Optional<ScalarEvolution::MonotonicPredicateType>
9506ScalarEvolution::getMonotonicPredicateType(const SCEVAddRecExpr *LHS,
                                         ICmpInst::Predicate Pred,
                                         Optional<const SCEV *> NumIter,
                                         const Instruction *Context) {
assert((!NumIter || !isa<SCEVCouldNotCompute>(*NumIter)) &&(((!NumIter || !isa<SCEVCouldNotCompute>(*NumIter)) &&
 "provided number of iterations must be computable!") ? static_cast
<void> (0) : __assert_fail ("(!NumIter || !isa<SCEVCouldNotCompute>(*NumIter)) && \"provided number of iterations must be computable!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9511, __PRETTY_FUNCTION__))
16
←
Assuming the condition is false→
17
←
Assuming the object is not a 'SCEVCouldNotCompute'→
18
←
'?' condition is true→
       "provided number of iterations must be computable!")(((!NumIter || !isa<SCEVCouldNotCompute>(*NumIter)) &&
 "provided number of iterations must be computable!") ? static_cast
<void> (0) : __assert_fail ("(!NumIter || !isa<SCEVCouldNotCompute>(*NumIter)) && \"provided number of iterations must be computable!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9511, __PRETTY_FUNCTION__));
auto Result = getMonotonicPredicateTypeImpl(LHS, Pred, NumIter, Context);
19
←
Passing null pointer value via 4th parameter 'Context'→
20
←
Calling 'ScalarEvolution::getMonotonicPredicateTypeImpl'→

9514#ifndef NDEBUG
// Verify an invariant: inverting the predicate should turn a monotonically
// increasing change to a monotonically decreasing one, and vice versa.
if (Result) {
  auto ResultSwapped = getMonotonicPredicateTypeImpl(
      LHS, ICmpInst::getSwappedPredicate(Pred), NumIter, Context);

  assert(ResultSwapped.hasValue() && "should be able to analyze both!")((ResultSwapped.hasValue() && "should be able to analyze both!"
) ? static_cast<void> (0) : __assert_fail ("ResultSwapped.hasValue() && \"should be able to analyze both!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9521, __PRETTY_FUNCTION__));
  assert(ResultSwapped.getValue() != Result.getValue() &&((ResultSwapped.getValue() != Result.getValue() && "monotonicity should flip as we flip the predicate"
) ? static_cast<void> (0) : __assert_fail ("ResultSwapped.getValue() != Result.getValue() && \"monotonicity should flip as we flip the predicate\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9523, __PRETTY_FUNCTION__))
         "monotonicity should flip as we flip the predicate")((ResultSwapped.getValue() != Result.getValue() && "monotonicity should flip as we flip the predicate"
) ? static_cast<void> (0) : __assert_fail ("ResultSwapped.getValue() != Result.getValue() && \"monotonicity should flip as we flip the predicate\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9523, __PRETTY_FUNCTION__));
}
9525#endif

return Result;
9528}

9530Optional<ScalarEvolution::MonotonicPredicateType>
9531ScalarEvolution::getMonotonicPredicateTypeImpl(const SCEVAddRecExpr *LHS,
                                             ICmpInst::Predicate Pred,
                                             Optional<const SCEV *> NumIter,
                                             const Instruction *Context) {
// A zero step value for LHS means the induction variable is essentially a
// loop invariant value. We don't really depend on the predicate actually
// flipping from false to true (for increasing predicates, and the other way
// around for decreasing predicates), all we care about is that *if* the
// predicate changes then it only changes from false to true.
//
// A zero step value in itself is not very useful, but there may be places
// where SCEV can prove X >= 0 but not prove X > 0, so it is helpful to be
// as general as possible.

// Only handle LE/LT/GE/GT predicates.
if (!ICmpInst::isRelational(Pred))
21
←
Taking false branch→
  return None;

bool IsGreater = ICmpInst::isGE(Pred) || ICmpInst::isGT(Pred);
assert((IsGreater || ICmpInst::isLE(Pred) || ICmpInst::isLT(Pred)) &&(((IsGreater || ICmpInst::isLE(Pred) || ICmpInst::isLT(Pred))
 && "Should be greater or less!") ? static_cast<void
> (0) : __assert_fail ("(IsGreater || ICmpInst::isLE(Pred) || ICmpInst::isLT(Pred)) && \"Should be greater or less!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9551, __PRETTY_FUNCTION__))
22
←
'?' condition is true→
       "Should be greater or less!")(((IsGreater || ICmpInst::isLE(Pred) || ICmpInst::isLT(Pred))
 && "Should be greater or less!") ? static_cast<void
> (0) : __assert_fail ("(IsGreater || ICmpInst::isLE(Pred) || ICmpInst::isLT(Pred)) && \"Should be greater or less!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9551, __PRETTY_FUNCTION__));

bool IsUnsigned = ICmpInst::isUnsigned(Pred);
assert((IsUnsigned || ICmpInst::isSigned(Pred)) &&(((IsUnsigned || ICmpInst::isSigned(Pred)) && "Should be either signed or unsigned!"
) ? static_cast<void> (0) : __assert_fail ("(IsUnsigned || ICmpInst::isSigned(Pred)) && \"Should be either signed or unsigned!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9555, __PRETTY_FUNCTION__))
23
←
Assuming 'IsUnsigned' is false→
24
←
Assuming the condition is true→
25
←
'?' condition is true→
       "Should be either signed or unsigned!")(((IsUnsigned || ICmpInst::isSigned(Pred)) && "Should be either signed or unsigned!"
) ? static_cast<void> (0) : __assert_fail ("(IsUnsigned || ICmpInst::isSigned(Pred)) && \"Should be either signed or unsigned!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9555, __PRETTY_FUNCTION__));
// Check if we can prove no-wrap in the relevant range.

const SCEV *Step = LHS->getStepRecurrence(*this);
bool IsStepNonNegative = isKnownNonNegative(Step);
bool IsStepNonPositive = isKnownNonPositive(Step);
// We need to know which direction the iteration is going.
if (!IsStepNonNegative && !IsStepNonPositive)
26
←
Assuming 'IsStepNonNegative' is true→
  return None;

auto ProvedNoWrap = [&]() {
  // If the AddRec already has the flag, we are done.
  if (IsUnsigned27.1
'IsUnsigned' is false
1
'IsUnsigned' is false
1
'IsUnsigned' is false
 ? LHS->hasNoUnsignedWrap() : LHS->hasNoSignedWrap())
28
←
'?' condition is false→
29
←
Calling 'SCEVNAryExpr::hasNoSignedWrap'→
32
←
Returning from 'SCEVNAryExpr::hasNoSignedWrap'→
33
←
Taking false branch→
    return true;

  if (!NumIter)
34
←
Calling 'Optional::operator bool'→
42
←
Returning from 'Optional::operator bool'→
43
←
Taking false branch→
    return false;
  // We could not prove no-wrap on all iteration space. Can we prove it for
  // first iterations? In order to achieve it, check that:
  // 1. The addrec does not self-wrap;
  // 2. start <= end for non-negative step and start >= end for non-positive
  // step.
  bool HasNoSelfWrap = LHS->hasNoSelfWrap();
44
←
Calling 'SCEVNAryExpr::hasNoSelfWrap'→
47
←
Returning from 'SCEVNAryExpr::hasNoSelfWrap'→
  if (!HasNoSelfWrap47.1
'HasNoSelfWrap' is true
1
'HasNoSelfWrap' is true
1
'HasNoSelfWrap' is true
)
48
←
Taking false branch→
    // If num iter has same type as the AddRec, and step is +/- 1, even max
    // possible number of iterations is not enough to self-wrap.
    if (NumIter.getValue()->getType() == LHS->getType())
      if (Step == getOne(LHS->getType()) ||
          Step == getMinusOne(LHS->getType()))
        HasNoSelfWrap = true;
  if (!HasNoSelfWrap48.1
'HasNoSelfWrap' is true
1
'HasNoSelfWrap' is true
1
'HasNoSelfWrap' is true
)
49
←
Taking false branch→
    return false;
  const SCEV *Start = LHS->getStart();
  const SCEV *End = LHS->evaluateAtIteration(*NumIter, *this);
  ICmpInst::Predicate NoOverflowPred =
      IsStepNonNegative49.1
'IsStepNonNegative' is true
1
'IsStepNonNegative' is true
1
'IsStepNonNegative' is true
 ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_SGE;
50
←
'?' condition is true→
  if (IsUnsigned50.1
'IsUnsigned' is false
1
'IsUnsigned' is false
1
'IsUnsigned' is false
)
51
←
Taking false branch→
    NoOverflowPred = ICmpInst::getUnsignedPredicate(NoOverflowPred);
  return isKnownPredicateAt(NoOverflowPred, Start, End, Context);
52
←
Passing null pointer value via 4th parameter 'Context'→
53
←
Calling 'ScalarEvolution::isKnownPredicateAt'→
};

// If nothing worked, bail.
if (!ProvedNoWrap())
27
←
Calling 'operator()'→
  return None;

if (IsUnsigned)
  return IsGreater ? MonotonicallyIncreasing : MonotonicallyDecreasing;
else {
  if (IsStepNonNegative)
    return IsGreater ? MonotonicallyIncreasing : MonotonicallyDecreasing;

  if (IsStepNonPositive)
    return !IsGreater ? MonotonicallyIncreasing : MonotonicallyDecreasing;

  return None;
}
9611}

9613Optional<ScalarEvolution::LoopInvariantPredicate>
9614ScalarEvolution::getLoopInvariantPredicate(ICmpInst::Predicate Pred,
                                         const SCEV *LHS, const SCEV *RHS,
                                         const Loop *L) {

// If there is a loop-invariant, force it into the RHS, otherwise bail out.
if (!isLoopInvariant(RHS, L)) {
1
Calling 'ScalarEvolution::isLoopInvariant'→
4
←
Returning from 'ScalarEvolution::isLoopInvariant'→
5
←
Taking true branch→
  if (!isLoopInvariant(LHS, L))
6
←
Calling 'ScalarEvolution::isLoopInvariant'→
9
←
Returning from 'ScalarEvolution::isLoopInvariant'→
10
←
Taking false branch→
    return None;

  std::swap(LHS, RHS);
  Pred = ICmpInst::getSwappedPredicate(Pred);
}

const SCEVAddRecExpr *ArLHS = dyn_cast<SCEVAddRecExpr>(LHS);
11
←
Assuming 'LHS' is a 'SCEVAddRecExpr'→
if (!ArLHS11.1
'ArLHS' is non-null
1
'ArLHS' is non-null
1
'ArLHS' is non-null
 || ArLHS->getLoop() != L)
12
←
Assuming the condition is false→
13
←
Taking false branch→
  return None;

auto MonotonicType = getMonotonicPredicateType(ArLHS, Pred);
14
←
Passing null pointer value via 4th parameter 'Context'→
15
←
Calling 'ScalarEvolution::getMonotonicPredicateType'→
if (!MonotonicType)
  return None;
// If the predicate "ArLHS `Pred` RHS" monotonically increases from false to
// true as the loop iterates, and the backedge is control dependent on
// "ArLHS `Pred` RHS" == true then we can reason as follows:
//
//   * if the predicate was false in the first iteration then the predicate
//     is never evaluated again, since the loop exits without taking the
//     backedge.
//   * if the predicate was true in the first iteration then it will
//     continue to be true for all future iterations since it is
//     monotonically increasing.
//
// For both the above possibilities, we can replace the loop varying
// predicate with its value on the first iteration of the loop (which is
// loop invariant).
//
// A similar reasoning applies for a monotonically decreasing predicate, by
// replacing true with false and false with true in the above two bullets.
bool Increasing = *MonotonicType == ScalarEvolution::MonotonicallyIncreasing;
auto P = Increasing ? Pred : ICmpInst::getInversePredicate(Pred);

if (!isLoopBackedgeGuardedByCond(L, P, LHS, RHS))
  return None;

return ScalarEvolution::LoopInvariantPredicate(Pred, ArLHS->getStart(), RHS);
9658}

9660Optional<ScalarEvolution::LoopInvariantPredicate>
9661ScalarEvolution::getLoopInvariantExitCondDuringFirstIterations(
  ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS, const Loop *L,
  const Instruction *Context, const SCEV *MaxIter) {
// Try to prove the following set of facts:
// - The predicate is monotonic in the iteration space.
// - If the check does not fail on the 1st iteration:
//   - It will not fail on the MaxIter'th iteration.
// If the check does fail on the 1st iteration, we leave the loop and no
// other checks matter.

// If there is a loop-invariant, force it into the RHS, otherwise bail out.
if (!isLoopInvariant(RHS, L)) {
  if (!isLoopInvariant(LHS, L))
    return None;

  std::swap(LHS, RHS);
  Pred = ICmpInst::getSwappedPredicate(Pred);
}

auto *AR = dyn_cast<SCEVAddRecExpr>(LHS);
if (!AR || AR->getLoop() != L)
  return None;

if (!getMonotonicPredicateType(AR, Pred, MaxIter, Context))
  return None;

// Value of IV on suggested last iteration.
const SCEV *Last = AR->evaluateAtIteration(MaxIter, *this);
// Does it still meet the requirement?
if (!isKnownPredicateAt(Pred, Last, RHS, Context))
  return None;

// Everything is fine.
return ScalarEvolution::LoopInvariantPredicate(Pred, AR->getStart(), RHS);
9695}

9697bool ScalarEvolution::isKnownPredicateViaConstantRanges(
  ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS) {
if (HasSameValue(LHS, RHS))
  return ICmpInst::isTrueWhenEqual(Pred);

// This code is split out from isKnownPredicate because it is called from
// within isLoopEntryGuardedByCond.

auto CheckRanges =
    [&](const ConstantRange &RangeLHS, const ConstantRange &RangeRHS) {
  return ConstantRange::makeSatisfyingICmpRegion(Pred, RangeRHS)
      .contains(RangeLHS);
};

// The check at the top of the function catches the case where the values are
// known to be equal.
if (Pred == CmpInst::ICMP_EQ)
  return false;

if (Pred == CmpInst::ICMP_NE)
  return CheckRanges(getSignedRange(LHS), getSignedRange(RHS)) ||
         CheckRanges(getUnsignedRange(LHS), getUnsignedRange(RHS)) ||
         isKnownNonZero(getMinusSCEV(LHS, RHS));

if (CmpInst::isSigned(Pred))
  return CheckRanges(getSignedRange(LHS), getSignedRange(RHS));

return CheckRanges(getUnsignedRange(LHS), getUnsignedRange(RHS));
9725}

9727bool ScalarEvolution::isKnownPredicateViaNoOverflow(ICmpInst::Predicate Pred,
                                                  const SCEV *LHS,
                                                  const SCEV *RHS) {
// Match Result to (X + Y)<ExpectedFlags> where Y is a constant integer.
// Return Y via OutY.
auto MatchBinaryAddToConst =
    [this](const SCEV *Result, const SCEV *X, APInt &OutY,
           SCEV::NoWrapFlags ExpectedFlags) {
  const SCEV *NonConstOp, *ConstOp;
  SCEV::NoWrapFlags FlagsPresent;

  if (!splitBinaryAdd(Result, ConstOp, NonConstOp, FlagsPresent) ||
      !isa<SCEVConstant>(ConstOp) || NonConstOp != X)
    return false;

  OutY = cast<SCEVConstant>(ConstOp)->getAPInt();
  return (FlagsPresent & ExpectedFlags) == ExpectedFlags;
};

APInt C;

switch (Pred) {
default:
  break;

case ICmpInst::ICMP_SGE:
  std::swap(LHS, RHS);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_SLE:
  // X s<= (X + C)<nsw> if C >= 0
  if (MatchBinaryAddToConst(RHS, LHS, C, SCEV::FlagNSW) && C.isNonNegative())
    return true;

  // (X + C)<nsw> s<= X if C <= 0
  if (MatchBinaryAddToConst(LHS, RHS, C, SCEV::FlagNSW) &&
      !C.isStrictlyPositive())
    return true;
  break;

case ICmpInst::ICMP_SGT:
  std::swap(LHS, RHS);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_SLT:
  // X s< (X + C)<nsw> if C > 0
  if (MatchBinaryAddToConst(RHS, LHS, C, SCEV::FlagNSW) &&
      C.isStrictlyPositive())
    return true;

  // (X + C)<nsw> s< X if C < 0
  if (MatchBinaryAddToConst(LHS, RHS, C, SCEV::FlagNSW) && C.isNegative())
    return true;
  break;

case ICmpInst::ICMP_UGE:
  std::swap(LHS, RHS);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_ULE:
  // X u<= (X + C)<nuw> for any C
  if (MatchBinaryAddToConst(RHS, LHS, C, SCEV::FlagNUW))
    return true;
  break;

case ICmpInst::ICMP_UGT:
  std::swap(LHS, RHS);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_ULT:
  // X u< (X + C)<nuw> if C != 0
  if (MatchBinaryAddToConst(RHS, LHS, C, SCEV::FlagNUW) && !C.isNullValue())
    return true;
  break;
}

return false;
9800}

9802bool ScalarEvolution::isKnownPredicateViaSplitting(ICmpInst::Predicate Pred,
                                                 const SCEV *LHS,
                                                 const SCEV *RHS) {
if (Pred != ICmpInst::ICMP_ULT || ProvingSplitPredicate)
  return false;

// Allowing arbitrary number of activations of isKnownPredicateViaSplitting on
// the stack can result in exponential time complexity.
SaveAndRestore<bool> Restore(ProvingSplitPredicate, true);

// If L >= 0 then I `ult` L <=> I >= 0 && I `slt` L
//
// To prove L >= 0 we use isKnownNonNegative whereas to prove I >= 0 we use
// isKnownPredicate.  isKnownPredicate is more powerful, but also more
// expensive; and using isKnownNonNegative(RHS) is sufficient for most of the
// interesting cases seen in practice.  We can consider "upgrading" L >= 0 to
// use isKnownPredicate later if needed.
return isKnownNonNegative(RHS) &&
       isKnownPredicate(CmpInst::ICMP_SGE, LHS, getZero(LHS->getType())) &&
       isKnownPredicate(CmpInst::ICMP_SLT, LHS, RHS);
9822}

9824bool ScalarEvolution::isImpliedViaGuard(const BasicBlock *BB,
                                      ICmpInst::Predicate Pred,
                                      const SCEV *LHS, const SCEV *RHS) {
// No need to even try if we know the module has no guards.
if (!HasGuards)
  return false;

return any_of(*BB, [&](const Instruction &I) {
  using namespace llvm::PatternMatch;

  Value *Condition;
  return match(&I, m_Intrinsic<Intrinsic::experimental_guard>(
                       m_Value(Condition))) &&
         isImpliedCond(Pred, LHS, RHS, Condition, false);
});
9839}

9841/// isLoopBackedgeGuardedByCond - Test whether the backedge of the loop is
9842/// protected by a conditional between LHS and RHS.  This is used to
9843/// to eliminate casts.
9844bool
9845ScalarEvolution::isLoopBackedgeGuardedByCond(const Loop *L,
                                           ICmpInst::Predicate Pred,
                                           const SCEV *LHS, const SCEV *RHS) {
// Interpret a null as meaning no loop, where there is obviously no guard
// (interprocedural conditions notwithstanding).
if (!L) return true;

if (VerifyIR)
  assert(!verifyFunction(*L->getHeader()->getParent(), &dbgs()) &&((!verifyFunction(*L->getHeader()->getParent(), &dbgs
()) && "This cannot be done on broken IR!") ? static_cast
<void> (0) : __assert_fail ("!verifyFunction(*L->getHeader()->getParent(), &dbgs()) && \"This cannot be done on broken IR!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9854, __PRETTY_FUNCTION__))
         "This cannot be done on broken IR!")((!verifyFunction(*L->getHeader()->getParent(), &dbgs
()) && "This cannot be done on broken IR!") ? static_cast
<void> (0) : __assert_fail ("!verifyFunction(*L->getHeader()->getParent(), &dbgs()) && \"This cannot be done on broken IR!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9854, __PRETTY_FUNCTION__));


if (isKnownViaNonRecursiveReasoning(Pred, LHS, RHS))
  return true;

BasicBlock *Latch = L->getLoopLatch();
if (!Latch)
  return false;

BranchInst *LoopContinuePredicate =
  dyn_cast<BranchInst>(Latch->getTerminator());
if (LoopContinuePredicate && LoopContinuePredicate->isConditional() &&
    isImpliedCond(Pred, LHS, RHS,
                  LoopContinuePredicate->getCondition(),
                  LoopContinuePredicate->getSuccessor(0) != L->getHeader()))
  return true;

// We don't want more than one activation of the following loops on the stack
// -- that can lead to O(n!) time complexity.
if (WalkingBEDominatingConds)
  return false;

SaveAndRestore<bool> ClearOnExit(WalkingBEDominatingConds, true);

// See if we can exploit a trip count to prove the predicate.
const auto &BETakenInfo = getBackedgeTakenInfo(L);
const SCEV *LatchBECount = BETakenInfo.getExact(Latch, this);
if (LatchBECount != getCouldNotCompute()) {
  // We know that Latch branches back to the loop header exactly
  // LatchBECount times.  This means the backdege condition at Latch is
  // equivalent to  "{0,+,1} u< LatchBECount".
  Type *Ty = LatchBECount->getType();
  auto NoWrapFlags = SCEV::NoWrapFlags(SCEV::FlagNUW | SCEV::FlagNW);
  const SCEV *LoopCounter =
    getAddRecExpr(getZero(Ty), getOne(Ty), L, NoWrapFlags);
  if (isImpliedCond(Pred, LHS, RHS, ICmpInst::ICMP_ULT, LoopCounter,
                    LatchBECount))
    return true;
}

// Check conditions due to any @llvm.assume intrinsics.
for (auto &AssumeVH : AC.assumptions()) {
  if (!AssumeVH)
    continue;
  auto *CI = cast<CallInst>(AssumeVH);
  if (!DT.dominates(CI, Latch->getTerminator()))
    continue;

  if (isImpliedCond(Pred, LHS, RHS, CI->getArgOperand(0), false))
    return true;
}

// If the loop is not reachable from the entry block, we risk running into an
// infinite loop as we walk up into the dom tree.  These loops do not matter
// anyway, so we just return a conservative answer when we see them.
if (!DT.isReachableFromEntry(L->getHeader()))
  return false;

if (isImpliedViaGuard(Latch, Pred, LHS, RHS))
  return true;

for (DomTreeNode *DTN = DT[Latch], *HeaderDTN = DT[L->getHeader()];
     DTN != HeaderDTN; DTN = DTN->getIDom()) {
  assert(DTN && "should reach the loop header before reaching the root!")((DTN && "should reach the loop header before reaching the root!"
) ? static_cast<void> (0) : __assert_fail ("DTN && \"should reach the loop header before reaching the root!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9918, __PRETTY_FUNCTION__));

  BasicBlock *BB = DTN->getBlock();
  if (isImpliedViaGuard(BB, Pred, LHS, RHS))
    return true;

  BasicBlock *PBB = BB->getSinglePredecessor();
  if (!PBB)
    continue;

  BranchInst *ContinuePredicate = dyn_cast<BranchInst>(PBB->getTerminator());
  if (!ContinuePredicate || !ContinuePredicate->isConditional())
    continue;

  Value *Condition = ContinuePredicate->getCondition();

  // If we have an edge `E` within the loop body that dominates the only
  // latch, the condition guarding `E` also guards the backedge.  This
  // reasoning works only for loops with a single latch.

  BasicBlockEdge DominatingEdge(PBB, BB);
  if (DominatingEdge.isSingleEdge()) {
    // We're constructively (and conservatively) enumerating edges within the
    // loop body that dominate the latch.  The dominator tree better agree
    // with us on this:
    assert(DT.dominates(DominatingEdge, Latch) && "should be!")((DT.dominates(DominatingEdge, Latch) && "should be!"
) ? static_cast<void> (0) : __assert_fail ("DT.dominates(DominatingEdge, Latch) && \"should be!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9943, __PRETTY_FUNCTION__));

    if (isImpliedCond(Pred, LHS, RHS, Condition,
                      BB != ContinuePredicate->getSuccessor(0)))
      return true;
  }
}

return false;
9952}

9954bool ScalarEvolution::isBasicBlockEntryGuardedByCond(const BasicBlock *BB,
                                                   ICmpInst::Predicate Pred,
                                                   const SCEV *LHS,
                                                   const SCEV *RHS) {
if (VerifyIR)
  assert(!verifyFunction(*BB->getParent(), &dbgs()) &&((!verifyFunction(*BB->getParent(), &dbgs()) &&
 "This cannot be done on broken IR!") ? static_cast<void>
 (0) : __assert_fail ("!verifyFunction(*BB->getParent(), &dbgs()) && \"This cannot be done on broken IR!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9960, __PRETTY_FUNCTION__))
         "This cannot be done on broken IR!")((!verifyFunction(*BB->getParent(), &dbgs()) &&
 "This cannot be done on broken IR!") ? static_cast<void>
 (0) : __assert_fail ("!verifyFunction(*BB->getParent(), &dbgs()) && \"This cannot be done on broken IR!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 9960, __PRETTY_FUNCTION__));

if (isKnownViaNonRecursiveReasoning(Pred, LHS, RHS))
  return true;

// If we cannot prove strict comparison (e.g. a > b), maybe we can prove
// the facts (a >= b && a != b) separately. A typical situation is when the
// non-strict comparison is known from ranges and non-equality is known from
// dominating predicates. If we are proving strict comparison, we always try
// to prove non-equality and non-strict comparison separately.
auto NonStrictPredicate = ICmpInst::getNonStrictPredicate(Pred);
const bool ProvingStrictComparison = (Pred != NonStrictPredicate);
bool ProvedNonStrictComparison = false;
bool ProvedNonEquality = false;

if (ProvingStrictComparison) {
  ProvedNonStrictComparison =
      isKnownViaNonRecursiveReasoning(NonStrictPredicate, LHS, RHS);
  ProvedNonEquality =
      isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_NE, LHS, RHS);
  if (ProvedNonStrictComparison && ProvedNonEquality)
    return true;
}

// Try to prove (Pred, LHS, RHS) using isImpliedViaGuard.
auto ProveViaGuard = [&](const BasicBlock *Block) {
  if (isImpliedViaGuard(Block, Pred, LHS, RHS))
    return true;
  if (ProvingStrictComparison) {
    if (!ProvedNonStrictComparison)
      ProvedNonStrictComparison =
          isImpliedViaGuard(Block, NonStrictPredicate, LHS, RHS);
    if (!ProvedNonEquality)
      ProvedNonEquality =
          isImpliedViaGuard(Block, ICmpInst::ICMP_NE, LHS, RHS);
    if (ProvedNonStrictComparison && ProvedNonEquality)
      return true;
  }
  return false;
};

// Try to prove (Pred, LHS, RHS) using isImpliedCond.
auto ProveViaCond = [&](const Value *Condition, bool Inverse) {
  const Instruction *Context = &BB->front();
  if (isImpliedCond(Pred, LHS, RHS, Condition, Inverse, Context))
    return true;
  if (ProvingStrictComparison) {
    if (!ProvedNonStrictComparison)
      ProvedNonStrictComparison = isImpliedCond(NonStrictPredicate, LHS, RHS,
                                                Condition, Inverse, Context);
    if (!ProvedNonEquality)
      ProvedNonEquality = isImpliedCond(ICmpInst::ICMP_NE, LHS, RHS,
                                        Condition, Inverse, Context);
    if (ProvedNonStrictComparison && ProvedNonEquality)
      return true;
  }
  return false;
};

// Starting at the block's predecessor, climb up the predecessor chain, as long
// as there are predecessors that can be found that have unique successors
// leading to the original block.
const Loop *ContainingLoop = LI.getLoopFor(BB);
const BasicBlock *PredBB;
if (ContainingLoop && ContainingLoop->getHeader() == BB)
  PredBB = ContainingLoop->getLoopPredecessor();
else
  PredBB = BB->getSinglePredecessor();
for (std::pair<const BasicBlock *, const BasicBlock *> Pair(PredBB, BB);
     Pair.first; Pair = getPredecessorWithUniqueSuccessorForBB(Pair.first)) {
  if (ProveViaGuard(Pair.first))
    return true;

  const BranchInst *LoopEntryPredicate =
      dyn_cast<BranchInst>(Pair.first->getTerminator());
  if (!LoopEntryPredicate ||
      LoopEntryPredicate->isUnconditional())
    continue;

  if (ProveViaCond(LoopEntryPredicate->getCondition(),
                   LoopEntryPredicate->getSuccessor(0) != Pair.second))
    return true;
}

// Check conditions due to any @llvm.assume intrinsics.
for (auto &AssumeVH : AC.assumptions()) {
  if (!AssumeVH)
    continue;
  auto *CI = cast<CallInst>(AssumeVH);
  if (!DT.dominates(CI, BB))
    continue;

  if (ProveViaCond(CI->getArgOperand(0), false))
    return true;
}

return false;
10057}

10059bool ScalarEvolution::isLoopEntryGuardedByCond(const Loop *L,
                                             ICmpInst::Predicate Pred,
                                             const SCEV *LHS,
                                             const SCEV *RHS) {
// Interpret a null as meaning no loop, where there is obviously no guard
// (interprocedural conditions notwithstanding).
if (!L)
  return false;

// Both LHS and RHS must be available at loop entry.
assert(isAvailableAtLoopEntry(LHS, L) &&((isAvailableAtLoopEntry(LHS, L) && "LHS is not available at Loop Entry"
) ? static_cast<void> (0) : __assert_fail ("isAvailableAtLoopEntry(LHS, L) && \"LHS is not available at Loop Entry\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10070, __PRETTY_FUNCTION__))
       "LHS is not available at Loop Entry")((isAvailableAtLoopEntry(LHS, L) && "LHS is not available at Loop Entry"
) ? static_cast<void> (0) : __assert_fail ("isAvailableAtLoopEntry(LHS, L) && \"LHS is not available at Loop Entry\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10070, __PRETTY_FUNCTION__));
assert(isAvailableAtLoopEntry(RHS, L) &&((isAvailableAtLoopEntry(RHS, L) && "RHS is not available at Loop Entry"
) ? static_cast<void> (0) : __assert_fail ("isAvailableAtLoopEntry(RHS, L) && \"RHS is not available at Loop Entry\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10072, __PRETTY_FUNCTION__))
       "RHS is not available at Loop Entry")((isAvailableAtLoopEntry(RHS, L) && "RHS is not available at Loop Entry"
) ? static_cast<void> (0) : __assert_fail ("isAvailableAtLoopEntry(RHS, L) && \"RHS is not available at Loop Entry\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10072, __PRETTY_FUNCTION__));
return isBasicBlockEntryGuardedByCond(L->getHeader(), Pred, LHS, RHS);
10074}

10076bool ScalarEvolution::isImpliedCond(ICmpInst::Predicate Pred, const SCEV *LHS,
                                  const SCEV *RHS,
                                  const Value *FoundCondValue, bool Inverse,
                                  const Instruction *Context) {
if (!PendingLoopPredicates.insert(FoundCondValue).second)
  return false;

auto ClearOnExit =
    make_scope_exit([&]() { PendingLoopPredicates.erase(FoundCondValue); });

// Recursively handle And and Or conditions.
if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(FoundCondValue)) {
  if (BO->getOpcode() == Instruction::And) {
    if (!Inverse)
      return isImpliedCond(Pred, LHS, RHS, BO->getOperand(0), Inverse,
                           Context) ||
             isImpliedCond(Pred, LHS, RHS, BO->getOperand(1), Inverse,
                           Context);
  } else if (BO->getOpcode() == Instruction::Or) {
    if (Inverse)
      return isImpliedCond(Pred, LHS, RHS, BO->getOperand(0), Inverse,
                           Context) ||
             isImpliedCond(Pred, LHS, RHS, BO->getOperand(1), Inverse,
                           Context);
  }
}

const ICmpInst *ICI = dyn_cast<ICmpInst>(FoundCondValue);
if (!ICI) return false;

// Now that we found a conditional branch that dominates the loop or controls
// the loop latch. Check to see if it is the comparison we are looking for.
ICmpInst::Predicate FoundPred;
if (Inverse)
  FoundPred = ICI->getInversePredicate();
else
  FoundPred = ICI->getPredicate();

const SCEV *FoundLHS = getSCEV(ICI->getOperand(0));
const SCEV *FoundRHS = getSCEV(ICI->getOperand(1));

return isImpliedCond(Pred, LHS, RHS, FoundPred, FoundLHS, FoundRHS, Context);
10118}

10120bool ScalarEvolution::isImpliedCond(ICmpInst::Predicate Pred, const SCEV *LHS,
                                  const SCEV *RHS,
                                  ICmpInst::Predicate FoundPred,
                                  const SCEV *FoundLHS, const SCEV *FoundRHS,
                                  const Instruction *Context) {
// Balance the types.
if (getTypeSizeInBits(LHS->getType()) <
    getTypeSizeInBits(FoundLHS->getType())) {
  // For unsigned and equality predicates, try to prove that both found
  // operands fit into narrow unsigned range. If so, try to prove facts in
  // narrow types.
  if (!CmpInst::isSigned(FoundPred)) {
    auto *NarrowType = LHS->getType();
    auto *WideType = FoundLHS->getType();
    auto BitWidth = getTypeSizeInBits(NarrowType);
    const SCEV *MaxValue = getZeroExtendExpr(
        getConstant(APInt::getMaxValue(BitWidth)), WideType);
    if (isKnownPredicate(ICmpInst::ICMP_ULE, FoundLHS, MaxValue) &&
        isKnownPredicate(ICmpInst::ICMP_ULE, FoundRHS, MaxValue)) {
      const SCEV *TruncFoundLHS = getTruncateExpr(FoundLHS, NarrowType);
      const SCEV *TruncFoundRHS = getTruncateExpr(FoundRHS, NarrowType);
      if (isImpliedCondBalancedTypes(Pred, LHS, RHS, FoundPred, TruncFoundLHS,
                                     TruncFoundRHS, Context))
        return true;
    }
  }

  if (CmpInst::isSigned(Pred)) {
    LHS = getSignExtendExpr(LHS, FoundLHS->getType());
    RHS = getSignExtendExpr(RHS, FoundLHS->getType());
  } else {
    LHS = getZeroExtendExpr(LHS, FoundLHS->getType());
    RHS = getZeroExtendExpr(RHS, FoundLHS->getType());
  }
} else if (getTypeSizeInBits(LHS->getType()) >
    getTypeSizeInBits(FoundLHS->getType())) {
  if (CmpInst::isSigned(FoundPred)) {
    FoundLHS = getSignExtendExpr(FoundLHS, LHS->getType());
    FoundRHS = getSignExtendExpr(FoundRHS, LHS->getType());
  } else {
    FoundLHS = getZeroExtendExpr(FoundLHS, LHS->getType());
    FoundRHS = getZeroExtendExpr(FoundRHS, LHS->getType());
  }
}
return isImpliedCondBalancedTypes(Pred, LHS, RHS, FoundPred, FoundLHS,
                                  FoundRHS, Context);
10166}

10168bool ScalarEvolution::isImpliedCondBalancedTypes(
  ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS,
  ICmpInst::Predicate FoundPred, const SCEV *FoundLHS, const SCEV *FoundRHS,
  const Instruction *Context) {
assert(getTypeSizeInBits(LHS->getType()) ==((getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(FoundLHS
->getType()) && "Types should be balanced!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(FoundLHS->getType()) && \"Types should be balanced!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10174, __PRETTY_FUNCTION__))
           getTypeSizeInBits(FoundLHS->getType()) &&((getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(FoundLHS
->getType()) && "Types should be balanced!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(FoundLHS->getType()) && \"Types should be balanced!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10174, __PRETTY_FUNCTION__))
       "Types should be balanced!")((getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(FoundLHS
->getType()) && "Types should be balanced!") ? static_cast
<void> (0) : __assert_fail ("getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(FoundLHS->getType()) && \"Types should be balanced!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10174, __PRETTY_FUNCTION__));
// Canonicalize the query to match the way instcombine will have
// canonicalized the comparison.
if (SimplifyICmpOperands(Pred, LHS, RHS))
  if (LHS == RHS)
    return CmpInst::isTrueWhenEqual(Pred);
if (SimplifyICmpOperands(FoundPred, FoundLHS, FoundRHS))
  if (FoundLHS == FoundRHS)
    return CmpInst::isFalseWhenEqual(FoundPred);

// Check to see if we can make the LHS or RHS match.
if (LHS == FoundRHS || RHS == FoundLHS) {
  if (isa<SCEVConstant>(RHS)) {
    std::swap(FoundLHS, FoundRHS);
    FoundPred = ICmpInst::getSwappedPredicate(FoundPred);
  } else {
    std::swap(LHS, RHS);
    Pred = ICmpInst::getSwappedPredicate(Pred);
  }
}

// Check whether the found predicate is the same as the desired predicate.
if (FoundPred == Pred)
  return isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS, Context);

// Check whether swapping the found predicate makes it the same as the
// desired predicate.
if (ICmpInst::getSwappedPredicate(FoundPred) == Pred) {
  if (isa<SCEVConstant>(RHS))
    return isImpliedCondOperands(Pred, LHS, RHS, FoundRHS, FoundLHS, Context);
  else
    return isImpliedCondOperands(ICmpInst::getSwappedPredicate(Pred), RHS,
                                 LHS, FoundLHS, FoundRHS, Context);
}

// Unsigned comparison is the same as signed comparison when both the operands
// are non-negative.
if (CmpInst::isUnsigned(FoundPred) &&
    CmpInst::getSignedPredicate(FoundPred) == Pred &&
    isKnownNonNegative(FoundLHS) && isKnownNonNegative(FoundRHS))
  return isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS, Context);

// Check if we can make progress by sharpening ranges.
if (FoundPred == ICmpInst::ICMP_NE &&
    (isa<SCEVConstant>(FoundLHS) || isa<SCEVConstant>(FoundRHS))) {

  const SCEVConstant *C = nullptr;
  const SCEV *V = nullptr;

  if (isa<SCEVConstant>(FoundLHS)) {
    C = cast<SCEVConstant>(FoundLHS);
    V = FoundRHS;
  } else {
    C = cast<SCEVConstant>(FoundRHS);
    V = FoundLHS;
  }

  // The guarding predicate tells us that C != V. If the known range
  // of V is [C, t), we can sharpen the range to [C + 1, t).  The
  // range we consider has to correspond to same signedness as the
  // predicate we're interested in folding.

  APInt Min = ICmpInst::isSigned(Pred) ?
      getSignedRangeMin(V) : getUnsignedRangeMin(V);

  if (Min == C->getAPInt()) {
    // Given (V >= Min && V != Min) we conclude V >= (Min + 1).
    // This is true even if (Min + 1) wraps around -- in case of
    // wraparound, (Min + 1) < Min, so (V >= Min => V >= (Min + 1)).

    APInt SharperMin = Min + 1;

    switch (Pred) {
      case ICmpInst::ICMP_SGE:
      case ICmpInst::ICMP_UGE:
        // We know V `Pred` SharperMin.  If this implies LHS `Pred`
        // RHS, we're done.
        if (isImpliedCondOperands(Pred, LHS, RHS, V, getConstant(SharperMin),
                                  Context))
          return true;
        LLVM_FALLTHROUGH[[gnu::fallthrough]];

      case ICmpInst::ICMP_SGT:
      case ICmpInst::ICMP_UGT:
        // We know from the range information that (V `Pred` Min ||
        // V == Min).  We know from the guarding condition that !(V
        // == Min).  This gives us
        //
        //       V `Pred` Min || V == Min && !(V == Min)
        //   =>  V `Pred` Min
        //
        // If V `Pred` Min implies LHS `Pred` RHS, we're done.

        if (isImpliedCondOperands(Pred, LHS, RHS, V, getConstant(Min),
                                  Context))
          return true;
        break;

      // `LHS < RHS` and `LHS <= RHS` are handled in the same way as `RHS > LHS` and `RHS >= LHS` respectively.
      case ICmpInst::ICMP_SLE:
      case ICmpInst::ICMP_ULE:
        if (isImpliedCondOperands(CmpInst::getSwappedPredicate(Pred), RHS,
                                  LHS, V, getConstant(SharperMin), Context))
          return true;
        LLVM_FALLTHROUGH[[gnu::fallthrough]];

      case ICmpInst::ICMP_SLT:
      case ICmpInst::ICMP_ULT:
        if (isImpliedCondOperands(CmpInst::getSwappedPredicate(Pred), RHS,
                                  LHS, V, getConstant(Min), Context))
          return true;
        break;

      default:
        // No change
        break;
    }
  }
}

// Check whether the actual condition is beyond sufficient.
if (FoundPred == ICmpInst::ICMP_EQ)
  if (ICmpInst::isTrueWhenEqual(Pred))
    if (isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, FoundRHS, Context))
      return true;
if (Pred == ICmpInst::ICMP_NE)
  if (!ICmpInst::isTrueWhenEqual(FoundPred))
    if (isImpliedCondOperands(FoundPred, LHS, RHS, FoundLHS, FoundRHS,
                              Context))
      return true;

// Otherwise assume the worst.
return false;
10307}

10309bool ScalarEvolution::splitBinaryAdd(const SCEV *Expr,
                                   const SCEV *&L, const SCEV *&R,
                                   SCEV::NoWrapFlags &Flags) {
const auto *AE = dyn_cast<SCEVAddExpr>(Expr);
if (!AE || AE->getNumOperands() != 2)
  return false;

L = AE->getOperand(0);
R = AE->getOperand(1);
Flags = AE->getNoWrapFlags();
return true;
10320}

10322Optional<APInt> ScalarEvolution::computeConstantDifference(const SCEV *More,
                                                         const SCEV *Less) {
// We avoid subtracting expressions here because this function is usually
// fairly deep in the call stack (i.e. is called many times).

// X - X = 0.
if (More == Less)
  return APInt(getTypeSizeInBits(More->getType()), 0);

if (isa<SCEVAddRecExpr>(Less) && isa<SCEVAddRecExpr>(More)) {
  const auto *LAR = cast<SCEVAddRecExpr>(Less);
  const auto *MAR = cast<SCEVAddRecExpr>(More);

  if (LAR->getLoop() != MAR->getLoop())
    return None;

  // We look at affine expressions only; not for correctness but to keep
  // getStepRecurrence cheap.
  if (!LAR->isAffine() || !MAR->isAffine())
    return None;

  if (LAR->getStepRecurrence(*this) != MAR->getStepRecurrence(*this))
    return None;

  Less = LAR->getStart();
  More = MAR->getStart();

  // fall through
}

if (isa<SCEVConstant>(Less) && isa<SCEVConstant>(More)) {
  const auto &M = cast<SCEVConstant>(More)->getAPInt();
  const auto &L = cast<SCEVConstant>(Less)->getAPInt();
  return M - L;
}

SCEV::NoWrapFlags Flags;
const SCEV *LLess = nullptr, *RLess = nullptr;
const SCEV *LMore = nullptr, *RMore = nullptr;
const SCEVConstant *C1 = nullptr, *C2 = nullptr;
// Compare (X + C1) vs X.
if (splitBinaryAdd(Less, LLess, RLess, Flags))
  if ((C1 = dyn_cast<SCEVConstant>(LLess)))
    if (RLess == More)
      return -(C1->getAPInt());

// Compare X vs (X + C2).
if (splitBinaryAdd(More, LMore, RMore, Flags))
  if ((C2 = dyn_cast<SCEVConstant>(LMore)))
    if (RMore == Less)
      return C2->getAPInt();

// Compare (X + C1) vs (X + C2).
if (C1 && C2 && RLess == RMore)
  return C2->getAPInt() - C1->getAPInt();

return None;
10379}

10381bool ScalarEvolution::isImpliedCondOperandsViaAddRecStart(
  ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS,
  const SCEV *FoundLHS, const SCEV *FoundRHS, const Instruction *Context) {
// Try to recognize the following pattern:
//
//   FoundRHS = ...
// ...
// loop:
//   FoundLHS = {Start,+,W}
// context_bb: // Basic block from the same loop
//   known(Pred, FoundLHS, FoundRHS)
//
// If some predicate is known in the context of a loop, it is also known on
// each iteration of this loop, including the first iteration. Therefore, in
// this case, `FoundLHS Pred FoundRHS` implies `Start Pred FoundRHS`. Try to
// prove the original pred using this fact.
if (!Context)
  return false;
const BasicBlock *ContextBB = Context->getParent();
// Make sure AR varies in the context block.
if (auto *AR = dyn_cast<SCEVAddRecExpr>(FoundLHS)) {
  const Loop *L = AR->getLoop();
  // Make sure that context belongs to the loop and executes on 1st iteration
  // (if it ever executes at all).
  if (!L->contains(ContextBB) || !DT.dominates(ContextBB, L->getLoopLatch()))
    return false;
  if (!isAvailableAtLoopEntry(FoundRHS, AR->getLoop()))
    return false;
  return isImpliedCondOperands(Pred, LHS, RHS, AR->getStart(), FoundRHS);
}

if (auto *AR = dyn_cast<SCEVAddRecExpr>(FoundRHS)) {
  const Loop *L = AR->getLoop();
  // Make sure that context belongs to the loop and executes on 1st iteration
  // (if it ever executes at all).
  if (!L->contains(ContextBB) || !DT.dominates(ContextBB, L->getLoopLatch()))
    return false;
  if (!isAvailableAtLoopEntry(FoundLHS, AR->getLoop()))
    return false;
  return isImpliedCondOperands(Pred, LHS, RHS, FoundLHS, AR->getStart());
}

return false;
10424}

10426bool ScalarEvolution::isImpliedCondOperandsViaNoOverflow(
  ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS,
  const SCEV *FoundLHS, const SCEV *FoundRHS) {
if (Pred != CmpInst::ICMP_SLT && Pred != CmpInst::ICMP_ULT)
  return false;

const auto *AddRecLHS = dyn_cast<SCEVAddRecExpr>(LHS);
if (!AddRecLHS)
  return false;

const auto *AddRecFoundLHS = dyn_cast<SCEVAddRecExpr>(FoundLHS);
if (!AddRecFoundLHS)
  return false;

// We'd like to let SCEV reason about control dependencies, so we constrain
// both the inequalities to be about add recurrences on the same loop.  This
// way we can use isLoopEntryGuardedByCond later.

const Loop *L = AddRecFoundLHS->getLoop();
if (L != AddRecLHS->getLoop())
  return false;

//  FoundLHS u< FoundRHS u< -C =>  (FoundLHS + C) u< (FoundRHS + C) ... (1)
//
//  FoundLHS s< FoundRHS s< INT_MIN - C => (FoundLHS + C) s< (FoundRHS + C)
//                                                                  ... (2)
//
// Informal proof for (2), assuming (1) [*]:
//
// We'll also assume (A s< B) <=> ((A + INT_MIN) u< (B + INT_MIN)) ... (3)[**]
//
// Then
//
//       FoundLHS s< FoundRHS s< INT_MIN - C
// <=>  (FoundLHS + INT_MIN) u< (FoundRHS + INT_MIN) u< -C   [ using (3) ]
// <=>  (FoundLHS + INT_MIN + C) u< (FoundRHS + INT_MIN + C) [ using (1) ]
// <=>  (FoundLHS + INT_MIN + C + INT_MIN) s<
//                        (FoundRHS + INT_MIN + C + INT_MIN) [ using (3) ]
// <=>  FoundLHS + C s< FoundRHS + C
//
// [*]: (1) can be proved by ruling out overflow.
//
// [**]: This can be proved by analyzing all the four possibilities:
//    (A s< 0, B s< 0), (A s< 0, B s>= 0), (A s>= 0, B s< 0) and
//    (A s>= 0, B s>= 0).
//
// Note:
// Despite (2), "FoundRHS s< INT_MIN - C" does not mean that "FoundRHS + C"
// will not sign underflow.  For instance, say FoundLHS = (i8 -128), FoundRHS
// = (i8 -127) and C = (i8 -100).  Then INT_MIN - C = (i8 -28), and FoundRHS
// s< (INT_MIN - C).  Lack of sign overflow / underflow in "FoundRHS + C" is
// neither necessary nor sufficient to prove "(FoundLHS + C) s< (FoundRHS +
// C)".

Optional<APInt> LDiff = computeConstantDifference(LHS, FoundLHS);
Optional<APInt> RDiff = computeConstantDifference(RHS, FoundRHS);
if (!LDiff || !RDiff || *LDiff != *RDiff)
  return false;

if (LDiff->isMinValue())
  return true;

APInt FoundRHSLimit;

if (Pred == CmpInst::ICMP_ULT) {
  FoundRHSLimit = -(*RDiff);
} else {
  assert(Pred == CmpInst::ICMP_SLT && "Checked above!")((Pred == CmpInst::ICMP_SLT && "Checked above!") ? static_cast
<void> (0) : __assert_fail ("Pred == CmpInst::ICMP_SLT && \"Checked above!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10493, __PRETTY_FUNCTION__));
  FoundRHSLimit = APInt::getSignedMinValue(getTypeSizeInBits(RHS->getType())) - *RDiff;
}

// Try to prove (1) or (2), as needed.
return isAvailableAtLoopEntry(FoundRHS, L) &&
       isLoopEntryGuardedByCond(L, Pred, FoundRHS,
                                getConstant(FoundRHSLimit));
10501}

10503bool ScalarEvolution::isImpliedViaMerge(ICmpInst::Predicate Pred,
                                      const SCEV *LHS, const SCEV *RHS,
                                      const SCEV *FoundLHS,
                                      const SCEV *FoundRHS, unsigned Depth) {
const PHINode *LPhi = nullptr, *RPhi = nullptr;

auto ClearOnExit = make_scope_exit([&]() {
  if (LPhi) {
    bool Erased = PendingMerges.erase(LPhi);
    assert(Erased && "Failed to erase LPhi!")((Erased && "Failed to erase LPhi!") ? static_cast<
void> (0) : __assert_fail ("Erased && \"Failed to erase LPhi!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10512, __PRETTY_FUNCTION__));
    (void)Erased;
  }
  if (RPhi) {
    bool Erased = PendingMerges.erase(RPhi);
    assert(Erased && "Failed to erase RPhi!")((Erased && "Failed to erase RPhi!") ? static_cast<
void> (0) : __assert_fail ("Erased && \"Failed to erase RPhi!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10517, __PRETTY_FUNCTION__));
    (void)Erased;
  }
});

// Find respective Phis and check that they are not being pending.
if (const SCEVUnknown *LU = dyn_cast<SCEVUnknown>(LHS))
  if (auto *Phi = dyn_cast<PHINode>(LU->getValue())) {
    if (!PendingMerges.insert(Phi).second)
      return false;
    LPhi = Phi;
  }
if (const SCEVUnknown *RU = dyn_cast<SCEVUnknown>(RHS))
  if (auto *Phi = dyn_cast<PHINode>(RU->getValue())) {
    // If we detect a loop of Phi nodes being processed by this method, for
    // example:
    //
    //   %a = phi i32 [ %some1, %preheader ], [ %b, %latch ]
    //   %b = phi i32 [ %some2, %preheader ], [ %a, %latch ]
    //
    // we don't want to deal with a case that complex, so return conservative
    // answer false.
    if (!PendingMerges.insert(Phi).second)
      return false;
    RPhi = Phi;
  }

// If none of LHS, RHS is a Phi, nothing to do here.
if (!LPhi && !RPhi)
  return false;

// If there is a SCEVUnknown Phi we are interested in, make it left.
if (!LPhi) {
  std::swap(LHS, RHS);
  std::swap(FoundLHS, FoundRHS);
  std::swap(LPhi, RPhi);
  Pred = ICmpInst::getSwappedPredicate(Pred);
}

assert(LPhi && "LPhi should definitely be a SCEVUnknown Phi!")((LPhi && "LPhi should definitely be a SCEVUnknown Phi!"
) ? static_cast<void> (0) : __assert_fail ("LPhi && \"LPhi should definitely be a SCEVUnknown Phi!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10556, __PRETTY_FUNCTION__));
const BasicBlock *LBB = LPhi->getParent();
const SCEVAddRecExpr *RAR = dyn_cast<SCEVAddRecExpr>(RHS);

auto ProvedEasily = [&](const SCEV *S1, const SCEV *S2) {
  return isKnownViaNonRecursiveReasoning(Pred, S1, S2) ||
         isImpliedCondOperandsViaRanges(Pred, S1, S2, FoundLHS, FoundRHS) ||
         isImpliedViaOperations(Pred, S1, S2, FoundLHS, FoundRHS, Depth);
};

if (RPhi && RPhi->getParent() == LBB) {
  // Case one: RHS is also a SCEVUnknown Phi from the same basic block.
  // If we compare two Phis from the same block, and for each entry block
  // the predicate is true for incoming values from this block, then the
  // predicate is also true for the Phis.
  for (const BasicBlock *IncBB : predecessors(LBB)) {
    const SCEV *L = getSCEV(LPhi->getIncomingValueForBlock(IncBB));
    const SCEV *R = getSCEV(RPhi->getIncomingValueForBlock(IncBB));
    if (!ProvedEasily(L, R))
      return false;
  }
} else if (RAR && RAR->getLoop()->getHeader() == LBB) {
  // Case two: RHS is also a Phi from the same basic block, and it is an
  // AddRec. It means that there is a loop which has both AddRec and Unknown
  // PHIs, for it we can compare incoming values of AddRec from above the loop
  // and latch with their respective incoming values of LPhi.
  // TODO: Generalize to handle loops with many inputs in a header.
  if (LPhi->getNumIncomingValues() != 2) return false;

  auto *RLoop = RAR->getLoop();
  auto *Predecessor = RLoop->getLoopPredecessor();
  assert(Predecessor && "Loop with AddRec with no predecessor?")((Predecessor && "Loop with AddRec with no predecessor?"
) ? static_cast<void> (0) : __assert_fail ("Predecessor && \"Loop with AddRec with no predecessor?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10587, __PRETTY_FUNCTION__));
  const SCEV *L1 = getSCEV(LPhi->getIncomingValueForBlock(Predecessor));
  if (!ProvedEasily(L1, RAR->getStart()))
    return false;
  auto *Latch = RLoop->getLoopLatch();
  assert(Latch && "Loop with AddRec with no latch?")((Latch && "Loop with AddRec with no latch?") ? static_cast
<void> (0) : __assert_fail ("Latch && \"Loop with AddRec with no latch?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10592, __PRETTY_FUNCTION__));
  const SCEV *L2 = getSCEV(LPhi->getIncomingValueForBlock(Latch));
  if (!ProvedEasily(L2, RAR->getPostIncExpr(*this)))
    return false;
} else {
  // In all other cases go over inputs of LHS and compare each of them to RHS,
  // the predicate is true for (LHS, RHS) if it is true for all such pairs.
  // At this point RHS is either a non-Phi, or it is a Phi from some block
  // different from LBB.
  for (const BasicBlock *IncBB : predecessors(LBB)) {
    // Check that RHS is available in this block.
    if (!dominates(RHS, IncBB))
      return false;
    const SCEV *L = getSCEV(LPhi->getIncomingValueForBlock(IncBB));
    if (!ProvedEasily(L, RHS))
      return false;
  }
}
return true;
10611}

10613bool ScalarEvolution::isImpliedCondOperands(ICmpInst::Predicate Pred,
                                          const SCEV *LHS, const SCEV *RHS,
                                          const SCEV *FoundLHS,
                                          const SCEV *FoundRHS,
                                          const Instruction *Context) {
if (isImpliedCondOperandsViaRanges(Pred, LHS, RHS, FoundLHS, FoundRHS))
  return true;

if (isImpliedCondOperandsViaNoOverflow(Pred, LHS, RHS, FoundLHS, FoundRHS))
  return true;

if (isImpliedCondOperandsViaAddRecStart(Pred, LHS, RHS, FoundLHS, FoundRHS,
                                        Context))
  return true;

return isImpliedCondOperandsHelper(Pred, LHS, RHS,
                                   FoundLHS, FoundRHS) ||
       // ~x < ~y --> x > y
       isImpliedCondOperandsHelper(Pred, LHS, RHS,
                                   getNotSCEV(FoundRHS),
                                   getNotSCEV(FoundLHS));
10634}

10636/// Is MaybeMinMaxExpr an (U|S)(Min|Max) of Candidate and some other values?
10637template <typename MinMaxExprType>
10638static bool IsMinMaxConsistingOf(const SCEV *MaybeMinMaxExpr,
                               const SCEV *Candidate) {
const MinMaxExprType *MinMaxExpr = dyn_cast<MinMaxExprType>(MaybeMinMaxExpr);
if (!MinMaxExpr)
  return false;

return find(MinMaxExpr->operands(), Candidate) != MinMaxExpr->op_end();
10645}

10647static bool IsKnownPredicateViaAddRecStart(ScalarEvolution &SE,
                                         ICmpInst::Predicate Pred,
                                         const SCEV *LHS, const SCEV *RHS) {
// If both sides are affine addrecs for the same loop, with equal
// steps, and we know the recurrences don't wrap, then we only
// need to check the predicate on the starting values.

if (!ICmpInst::isRelational(Pred))
  return false;

const SCEVAddRecExpr *LAR = dyn_cast<SCEVAddRecExpr>(LHS);
if (!LAR)
  return false;
const SCEVAddRecExpr *RAR = dyn_cast<SCEVAddRecExpr>(RHS);
if (!RAR)
  return false;
if (LAR->getLoop() != RAR->getLoop())
  return false;
if (!LAR->isAffine() || !RAR->isAffine())
  return false;

if (LAR->getStepRecurrence(SE) != RAR->getStepRecurrence(SE))
  return false;

SCEV::NoWrapFlags NW = ICmpInst::isSigned(Pred) ?
                       SCEV::FlagNSW : SCEV::FlagNUW;
if (!LAR->getNoWrapFlags(NW) || !RAR->getNoWrapFlags(NW))
  return false;

return SE.isKnownPredicate(Pred, LAR->getStart(), RAR->getStart());
10677}

10679/// Is LHS `Pred` RHS true on the virtue of LHS or RHS being a Min or Max
10680/// expression?
10681static bool IsKnownPredicateViaMinOrMax(ScalarEvolution &SE,
                                      ICmpInst::Predicate Pred,
                                      const SCEV *LHS, const SCEV *RHS) {
switch (Pred) {
default:
  return false;

case ICmpInst::ICMP_SGE:
  std::swap(LHS, RHS);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_SLE:
  return
      // min(A, ...) <= A
      IsMinMaxConsistingOf<SCEVSMinExpr>(LHS, RHS) ||
      // A <= max(A, ...)
      IsMinMaxConsistingOf<SCEVSMaxExpr>(RHS, LHS);

case ICmpInst::ICMP_UGE:
  std::swap(LHS, RHS);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_ULE:
  return
      // min(A, ...) <= A
      IsMinMaxConsistingOf<SCEVUMinExpr>(LHS, RHS) ||
      // A <= max(A, ...)
      IsMinMaxConsistingOf<SCEVUMaxExpr>(RHS, LHS);
}

llvm_unreachable("covered switch fell through?!")::llvm::llvm_unreachable_internal("covered switch fell through?!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10709);
10710}

10712bool ScalarEvolution::isImpliedViaOperations(ICmpInst::Predicate Pred,
                                           const SCEV *LHS, const SCEV *RHS,
                                           const SCEV *FoundLHS,
                                           const SCEV *FoundRHS,
                                           unsigned Depth) {
assert(getTypeSizeInBits(LHS->getType()) ==((getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS
->getType()) && "LHS and RHS have different sizes?"
) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS->getType()) && \"LHS and RHS have different sizes?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10719, __PRETTY_FUNCTION__))
           getTypeSizeInBits(RHS->getType()) &&((getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS
->getType()) && "LHS and RHS have different sizes?"
) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS->getType()) && \"LHS and RHS have different sizes?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10719, __PRETTY_FUNCTION__))
       "LHS and RHS have different sizes?")((getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS
->getType()) && "LHS and RHS have different sizes?"
) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(LHS->getType()) == getTypeSizeInBits(RHS->getType()) && \"LHS and RHS have different sizes?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10719, __PRETTY_FUNCTION__));
assert(getTypeSizeInBits(FoundLHS->getType()) ==((getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits
(FoundRHS->getType()) && "FoundLHS and FoundRHS have different sizes?"
) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits(FoundRHS->getType()) && \"FoundLHS and FoundRHS have different sizes?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10722, __PRETTY_FUNCTION__))
           getTypeSizeInBits(FoundRHS->getType()) &&((getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits
(FoundRHS->getType()) && "FoundLHS and FoundRHS have different sizes?"
) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits(FoundRHS->getType()) && \"FoundLHS and FoundRHS have different sizes?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10722, __PRETTY_FUNCTION__))
       "FoundLHS and FoundRHS have different sizes?")((getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits
(FoundRHS->getType()) && "FoundLHS and FoundRHS have different sizes?"
) ? static_cast<void> (0) : __assert_fail ("getTypeSizeInBits(FoundLHS->getType()) == getTypeSizeInBits(FoundRHS->getType()) && \"FoundLHS and FoundRHS have different sizes?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10722, __PRETTY_FUNCTION__));
// We want to avoid hurting the compile time with analysis of too big trees.
if (Depth > MaxSCEVOperationsImplicationDepth)
  return false;

// We only want to work with GT comparison so far.
if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_SLT) {
  Pred = CmpInst::getSwappedPredicate(Pred);
  std::swap(LHS, RHS);
  std::swap(FoundLHS, FoundRHS);
}

// For unsigned, try to reduce it to corresponding signed comparison.
if (Pred == ICmpInst::ICMP_UGT)
  // We can replace unsigned predicate with its signed counterpart if all
  // involved values are non-negative.
  // TODO: We could have better support for unsigned.
  if (isKnownNonNegative(FoundLHS) && isKnownNonNegative(FoundRHS)) {
    // Knowing that both FoundLHS and FoundRHS are non-negative, and knowing
    // FoundLHS >u FoundRHS, we also know that FoundLHS >s FoundRHS. Let us
    // use this fact to prove that LHS and RHS are non-negative.
    const SCEV *MinusOne = getMinusOne(LHS->getType());
    if (isImpliedCondOperands(ICmpInst::ICMP_SGT, LHS, MinusOne, FoundLHS,
                              FoundRHS) &&
        isImpliedCondOperands(ICmpInst::ICMP_SGT, RHS, MinusOne, FoundLHS,
                              FoundRHS))
      Pred = ICmpInst::ICMP_SGT;
  }

if (Pred != ICmpInst::ICMP_SGT)
  return false;

auto GetOpFromSExt = [&](const SCEV *S) {
  if (auto *Ext = dyn_cast<SCEVSignExtendExpr>(S))
    return Ext->getOperand();
  // TODO: If S is a SCEVConstant then you can cheaply "strip" the sext off
  // the constant in some cases.
  return S;
};

// Acquire values from extensions.
auto *OrigLHS = LHS;
auto *OrigFoundLHS = FoundLHS;
LHS = GetOpFromSExt(LHS);
FoundLHS = GetOpFromSExt(FoundLHS);

// Is the SGT predicate can be proved trivially or using the found context.
auto IsSGTViaContext = [&](const SCEV *S1, const SCEV *S2) {
  return isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SGT, S1, S2) ||
         isImpliedViaOperations(ICmpInst::ICMP_SGT, S1, S2, OrigFoundLHS,
                                FoundRHS, Depth + 1);
};

if (auto *LHSAddExpr = dyn_cast<SCEVAddExpr>(LHS)) {
  // We want to avoid creation of any new non-constant SCEV. Since we are
  // going to compare the operands to RHS, we should be certain that we don't
  // need any size extensions for this. So let's decline all cases when the
  // sizes of types of LHS and RHS do not match.
  // TODO: Maybe try to get RHS from sext to catch more cases?
  if (getTypeSizeInBits(LHS->getType()) != getTypeSizeInBits(RHS->getType()))
    return false;

  // Should not overflow.
  if (!LHSAddExpr->hasNoSignedWrap())
    return false;

  auto *LL = LHSAddExpr->getOperand(0);
  auto *LR = LHSAddExpr->getOperand(1);
  auto *MinusOne = getMinusOne(RHS->getType());

  // Checks that S1 >= 0 && S2 > RHS, trivially or using the found context.
  auto IsSumGreaterThanRHS = [&](const SCEV *S1, const SCEV *S2) {
    return IsSGTViaContext(S1, MinusOne) && IsSGTViaContext(S2, RHS);
  };
  // Try to prove the following rule:
  // (LHS = LL + LR) && (LL >= 0) && (LR > RHS) => (LHS > RHS).
  // (LHS = LL + LR) && (LR >= 0) && (LL > RHS) => (LHS > RHS).
  if (IsSumGreaterThanRHS(LL, LR) || IsSumGreaterThanRHS(LR, LL))
    return true;
} else if (auto *LHSUnknownExpr = dyn_cast<SCEVUnknown>(LHS)) {
  Value *LL, *LR;
  // FIXME: Once we have SDiv implemented, we can get rid of this matching.

  using namespace llvm::PatternMatch;

  if (match(LHSUnknownExpr->getValue(), m_SDiv(m_Value(LL), m_Value(LR)))) {
    // Rules for division.
    // We are going to perform some comparisons with Denominator and its
    // derivative expressions. In general case, creating a SCEV for it may
    // lead to a complex analysis of the entire graph, and in particular it
    // can request trip count recalculation for the same loop. This would
    // cache as SCEVCouldNotCompute to avoid the infinite recursion. To avoid
    // this, we only want to create SCEVs that are constants in this section.
    // So we bail if Denominator is not a constant.
    if (!isa<ConstantInt>(LR))
      return false;

    auto *Denominator = cast<SCEVConstant>(getSCEV(LR));

    // We want to make sure that LHS = FoundLHS / Denominator. If it is so,
    // then a SCEV for the numerator already exists and matches with FoundLHS.
    auto *Numerator = getExistingSCEV(LL);
    if (!Numerator || Numerator->getType() != FoundLHS->getType())
      return false;

    // Make sure that the numerator matches with FoundLHS and the denominator
    // is positive.
    if (!HasSameValue(Numerator, FoundLHS) || !isKnownPositive(Denominator))
      return false;

    auto *DTy = Denominator->getType();
    auto *FRHSTy = FoundRHS->getType();
    if (DTy->isPointerTy() != FRHSTy->isPointerTy())
      // One of types is a pointer and another one is not. We cannot extend
      // them properly to a wider type, so let us just reject this case.
      // TODO: Usage of getEffectiveSCEVType for DTy, FRHSTy etc should help
      // to avoid this check.
      return false;

    // Given that:
    // FoundLHS > FoundRHS, LHS = FoundLHS / Denominator, Denominator > 0.
    auto *WTy = getWiderType(DTy, FRHSTy);
    auto *DenominatorExt = getNoopOrSignExtend(Denominator, WTy);
    auto *FoundRHSExt = getNoopOrSignExtend(FoundRHS, WTy);

    // Try to prove the following rule:
    // (FoundRHS > Denominator - 2) && (RHS <= 0) => (LHS > RHS).
    // For example, given that FoundLHS > 2. It means that FoundLHS is at
    // least 3. If we divide it by Denominator < 4, we will have at least 1.
    auto *DenomMinusTwo = getMinusSCEV(DenominatorExt, getConstant(WTy, 2));
    if (isKnownNonPositive(RHS) &&
        IsSGTViaContext(FoundRHSExt, DenomMinusTwo))
      return true;

    // Try to prove the following rule:
    // (FoundRHS > -1 - Denominator) && (RHS < 0) => (LHS > RHS).
    // For example, given that FoundLHS > -3. Then FoundLHS is at least -2.
    // If we divide it by Denominator > 2, then:
    // 1. If FoundLHS is negative, then the result is 0.
    // 2. If FoundLHS is non-negative, then the result is non-negative.
    // Anyways, the result is non-negative.
    auto *MinusOne = getMinusOne(WTy);
    auto *NegDenomMinusOne = getMinusSCEV(MinusOne, DenominatorExt);
    if (isKnownNegative(RHS) &&
        IsSGTViaContext(FoundRHSExt, NegDenomMinusOne))
      return true;
  }
}

// If our expression contained SCEVUnknown Phis, and we split it down and now
// need to prove something for them, try to prove the predicate for every
// possible incoming values of those Phis.
if (isImpliedViaMerge(Pred, OrigLHS, RHS, OrigFoundLHS, FoundRHS, Depth + 1))
  return true;

return false;
10878}

10880static bool isKnownPredicateExtendIdiom(ICmpInst::Predicate Pred,
                                      const SCEV *LHS, const SCEV *RHS) {
// zext x u<= sext x, sext x s<= zext x
switch (Pred) {
case ICmpInst::ICMP_SGE:
  std::swap(LHS, RHS);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_SLE: {
  // If operand >=s 0 then ZExt == SExt.  If operand <s 0 then SExt <s ZExt.
  const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(LHS);
  const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(RHS);
  if (SExt && ZExt && SExt->getOperand() == ZExt->getOperand())
    return true;
  break;
}
case ICmpInst::ICMP_UGE:
  std::swap(LHS, RHS);
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
case ICmpInst::ICMP_ULE: {
  // If operand >=s 0 then ZExt == SExt.  If operand <s 0 then ZExt <u SExt.
  const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(LHS);
  const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(RHS);
  if (SExt && ZExt && SExt->getOperand() == ZExt->getOperand())
    return true;
  break;
}
default:
  break;
};
return false;
10910}

10912bool
10913ScalarEvolution::isKnownViaNonRecursiveReasoning(ICmpInst::Predicate Pred,
                                         const SCEV *LHS, const SCEV *RHS) {
return isKnownPredicateExtendIdiom(Pred, LHS, RHS) ||
       isKnownPredicateViaConstantRanges(Pred, LHS, RHS) ||
       IsKnownPredicateViaMinOrMax(*this, Pred, LHS, RHS) ||
       IsKnownPredicateViaAddRecStart(*this, Pred, LHS, RHS) ||
       isKnownPredicateViaNoOverflow(Pred, LHS, RHS);
10920}

10922bool
10923ScalarEvolution::isImpliedCondOperandsHelper(ICmpInst::Predicate Pred,
                                           const SCEV *LHS, const SCEV *RHS,
                                           const SCEV *FoundLHS,
                                           const SCEV *FoundRHS) {
switch (Pred) {
default: llvm_unreachable("Unexpected ICmpInst::Predicate value!")::llvm::llvm_unreachable_internal("Unexpected ICmpInst::Predicate value!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 10928);
case ICmpInst::ICMP_EQ:
case ICmpInst::ICMP_NE:
  if (HasSameValue(LHS, FoundLHS) && HasSameValue(RHS, FoundRHS))
    return true;
  break;
case ICmpInst::ICMP_SLT:
case ICmpInst::ICMP_SLE:
  if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SLE, LHS, FoundLHS) &&
      isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SGE, RHS, FoundRHS))
    return true;
  break;
case ICmpInst::ICMP_SGT:
case ICmpInst::ICMP_SGE:
  if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SGE, LHS, FoundLHS) &&
      isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_SLE, RHS, FoundRHS))
    return true;
  break;
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_ULE:
  if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_ULE, LHS, FoundLHS) &&
      isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_UGE, RHS, FoundRHS))
    return true;
  break;
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_UGE:
  if (isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_UGE, LHS, FoundLHS) &&
      isKnownViaNonRecursiveReasoning(ICmpInst::ICMP_ULE, RHS, FoundRHS))
    return true;
  break;
}

// Maybe it can be proved via operations?
if (isImpliedViaOperations(Pred, LHS, RHS, FoundLHS, FoundRHS))
  return true;

return false;
10965}

10967bool ScalarEvolution::isImpliedCondOperandsViaRanges(ICmpInst::Predicate Pred,
                                                   const SCEV *LHS,
                                                   const SCEV *RHS,
                                                   const SCEV *FoundLHS,
                                                   const SCEV *FoundRHS) {
if (!isa<SCEVConstant>(RHS) || !isa<SCEVConstant>(FoundRHS))
  // The restriction on `FoundRHS` be lifted easily -- it exists only to
  // reduce the compile time impact of this optimization.
  return false;

Optional<APInt> Addend = computeConstantDifference(LHS, FoundLHS);
if (!Addend)
  return false;

const APInt &ConstFoundRHS = cast<SCEVConstant>(FoundRHS)->getAPInt();

// `FoundLHSRange` is the range we know `FoundLHS` to be in by virtue of the
// antecedent "`FoundLHS` `Pred` `FoundRHS`".
ConstantRange FoundLHSRange =
    ConstantRange::makeAllowedICmpRegion(Pred, ConstFoundRHS);

// Since `LHS` is `FoundLHS` + `Addend`, we can compute a range for `LHS`:
ConstantRange LHSRange = FoundLHSRange.add(ConstantRange(*Addend));

// We can also compute the range of values for `LHS` that satisfy the
// consequent, "`LHS` `Pred` `RHS`":
const APInt &ConstRHS = cast<SCEVConstant>(RHS)->getAPInt();
ConstantRange SatisfyingLHSRange =
    ConstantRange::makeSatisfyingICmpRegion(Pred, ConstRHS);

// The antecedent implies the consequent if every value of `LHS` that
// satisfies the antecedent also satisfies the consequent.
return SatisfyingLHSRange.contains(LHSRange);
11000}

11002bool ScalarEvolution::doesIVOverflowOnLT(const SCEV *RHS, const SCEV *Stride,
                                       bool IsSigned, bool NoWrap) {
assert(isKnownPositive(Stride) && "Positive stride expected!")((isKnownPositive(Stride) && "Positive stride expected!"
) ? static_cast<void> (0) : __assert_fail ("isKnownPositive(Stride) && \"Positive stride expected!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11004, __PRETTY_FUNCTION__));

if (NoWrap) return false;

unsigned BitWidth = getTypeSizeInBits(RHS->getType());
const SCEV *One = getOne(Stride->getType());

if (IsSigned) {
  APInt MaxRHS = getSignedRangeMax(RHS);
  APInt MaxValue = APInt::getSignedMaxValue(BitWidth);
  APInt MaxStrideMinusOne = getSignedRangeMax(getMinusSCEV(Stride, One));

  // SMaxRHS + SMaxStrideMinusOne > SMaxValue => overflow!
  return (std::move(MaxValue) - MaxStrideMinusOne).slt(MaxRHS);
}

APInt MaxRHS = getUnsignedRangeMax(RHS);
APInt MaxValue = APInt::getMaxValue(BitWidth);
APInt MaxStrideMinusOne = getUnsignedRangeMax(getMinusSCEV(Stride, One));

// UMaxRHS + UMaxStrideMinusOne > UMaxValue => overflow!
return (std::move(MaxValue) - MaxStrideMinusOne).ult(MaxRHS);
11026}

11028bool ScalarEvolution::doesIVOverflowOnGT(const SCEV *RHS, const SCEV *Stride,
                                       bool IsSigned, bool NoWrap) {
if (NoWrap) return false;

unsigned BitWidth = getTypeSizeInBits(RHS->getType());
const SCEV *One = getOne(Stride->getType());

if (IsSigned) {
  APInt MinRHS = getSignedRangeMin(RHS);
  APInt MinValue = APInt::getSignedMinValue(BitWidth);
  APInt MaxStrideMinusOne = getSignedRangeMax(getMinusSCEV(Stride, One));

  // SMinRHS - SMaxStrideMinusOne < SMinValue => overflow!
  return (std::move(MinValue) + MaxStrideMinusOne).sgt(MinRHS);
}

APInt MinRHS = getUnsignedRangeMin(RHS);
APInt MinValue = APInt::getMinValue(BitWidth);
APInt MaxStrideMinusOne = getUnsignedRangeMax(getMinusSCEV(Stride, One));

// UMinRHS - UMaxStrideMinusOne < UMinValue => overflow!
return (std::move(MinValue) + MaxStrideMinusOne).ugt(MinRHS);
11050}

11052const SCEV *ScalarEvolution::computeBECount(const SCEV *Delta, const SCEV *Step,
                                          bool Equality) {
const SCEV *One = getOne(Step->getType());
Delta = Equality ? getAddExpr(Delta, Step)
                 : getAddExpr(Delta, getMinusSCEV(Step, One));
return getUDivExpr(Delta, Step);
11058}

11060const SCEV *ScalarEvolution::computeMaxBECountForLT(const SCEV *Start,
                                                  const SCEV *Stride,
                                                  const SCEV *End,
                                                  unsigned BitWidth,
                                                  bool IsSigned) {

assert(!isKnownNonPositive(Stride) &&((!isKnownNonPositive(Stride) && "Stride is expected strictly positive!"
) ? static_cast<void> (0) : __assert_fail ("!isKnownNonPositive(Stride) && \"Stride is expected strictly positive!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11067, __PRETTY_FUNCTION__))
       "Stride is expected strictly positive!")((!isKnownNonPositive(Stride) && "Stride is expected strictly positive!"
) ? static_cast<void> (0) : __assert_fail ("!isKnownNonPositive(Stride) && \"Stride is expected strictly positive!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11067, __PRETTY_FUNCTION__));
// Calculate the maximum backedge count based on the range of values
// permitted by Start, End, and Stride.
const SCEV *MaxBECount;
APInt MinStart =
    IsSigned ? getSignedRangeMin(Start) : getUnsignedRangeMin(Start);

APInt StrideForMaxBECount =
    IsSigned ? getSignedRangeMin(Stride) : getUnsignedRangeMin(Stride);

// We already know that the stride is positive, so we paper over conservatism
// in our range computation by forcing StrideForMaxBECount to be at least one.
// In theory this is unnecessary, but we expect MaxBECount to be a
// SCEVConstant, and (udiv <constant> 0) is not constant folded by SCEV (there
// is nothing to constant fold it to).
APInt One(BitWidth, 1, IsSigned);
StrideForMaxBECount = APIntOps::smax(One, StrideForMaxBECount);

APInt MaxValue = IsSigned ? APInt::getSignedMaxValue(BitWidth)
                          : APInt::getMaxValue(BitWidth);
APInt Limit = MaxValue - (StrideForMaxBECount - 1);

// Although End can be a MAX expression we estimate MaxEnd considering only
// the case End = RHS of the loop termination condition. This is safe because
// in the other case (End - Start) is zero, leading to a zero maximum backedge
// taken count.
APInt MaxEnd = IsSigned ? APIntOps::smin(getSignedRangeMax(End), Limit)
                        : APIntOps::umin(getUnsignedRangeMax(End), Limit);

MaxBECount = computeBECount(getConstant(MaxEnd - MinStart) /* Delta */,
                            getConstant(StrideForMaxBECount) /* Step */,
                            false /* Equality */);

return MaxBECount;
11101}

11103ScalarEvolution::ExitLimit
11104ScalarEvolution::howManyLessThans(const SCEV *LHS, const SCEV *RHS,
                                const Loop *L, bool IsSigned,
                                bool ControlsExit, bool AllowPredicates) {
SmallPtrSet<const SCEVPredicate *, 4> Predicates;

const SCEVAddRecExpr *IV = dyn_cast<SCEVAddRecExpr>(LHS);
bool PredicatedIV = false;

if (!IV && AllowPredicates) {
  // Try to make this an AddRec using runtime tests, in the first X
  // iterations of this loop, where X is the SCEV expression found by the
  // algorithm below.
  IV = convertSCEVToAddRecWithPredicates(LHS, L, Predicates);
  PredicatedIV = true;
}

// Avoid weird loops
if (!IV || IV->getLoop() != L || !IV->isAffine())
  return getCouldNotCompute();

bool NoWrap = ControlsExit &&
              IV->getNoWrapFlags(IsSigned ? SCEV::FlagNSW : SCEV::FlagNUW);

const SCEV *Stride = IV->getStepRecurrence(*this);

bool PositiveStride = isKnownPositive(Stride);

// Avoid negative or zero stride values.
if (!PositiveStride) {
  // We can compute the correct backedge taken count for loops with unknown
  // strides if we can prove that the loop is not an infinite loop with side
  // effects. Here's the loop structure we are trying to handle -
  //
  // i = start
  // do {
  //   A[i] = i;
  //   i += s;
  // } while (i < end);
  //
  // The backedge taken count for such loops is evaluated as -
  // (max(end, start + stride) - start - 1) /u stride
  //
  // The additional preconditions that we need to check to prove correctness
  // of the above formula is as follows -
  //
  // a) IV is either nuw or nsw depending upon signedness (indicated by the
  //    NoWrap flag).
  // b) loop is single exit with no side effects.
  //
  //
  // Precondition a) implies that if the stride is negative, this is a single
  // trip loop. The backedge taken count formula reduces to zero in this case.
  //
  // Precondition b) implies that the unknown stride cannot be zero otherwise
  // we have UB.
  //
  // The positive stride case is the same as isKnownPositive(Stride) returning
  // true (original behavior of the function).
  //
  // We want to make sure that the stride is truly unknown as there are edge
  // cases where ScalarEvolution propagates no wrap flags to the
  // post-increment/decrement IV even though the increment/decrement operation
  // itself is wrapping. The computed backedge taken count may be wrong in
  // such cases. This is prevented by checking that the stride is not known to
  // be either positive or non-positive. For example, no wrap flags are
  // propagated to the post-increment IV of this loop with a trip count of 2 -
  //
  // unsigned char i;
  // for(i=127; i<128; i+=129)
  //   A[i] = i;
  //
  if (PredicatedIV || !NoWrap || isKnownNonPositive(Stride) ||
      !loopHasNoSideEffects(L))
    return getCouldNotCompute();
} else if (!Stride->isOne() &&
           doesIVOverflowOnLT(RHS, Stride, IsSigned, NoWrap))
  // Avoid proven overflow cases: this will ensure that the backedge taken
  // count will not generate any unsigned overflow. Relaxed no-overflow
  // conditions exploit NoWrapFlags, allowing to optimize in presence of
  // undefined behaviors like the case of C language.
  return getCouldNotCompute();

ICmpInst::Predicate Cond = IsSigned ? ICmpInst::ICMP_SLT
                                    : ICmpInst::ICMP_ULT;
const SCEV *Start = IV->getStart();
const SCEV *End = RHS;
// When the RHS is not invariant, we do not know the end bound of the loop and
// cannot calculate the ExactBECount needed by ExitLimit. However, we can
// calculate the MaxBECount, given the start, stride and max value for the end
// bound of the loop (RHS), and the fact that IV does not overflow (which is
// checked above).
if (!isLoopInvariant(RHS, L)) {
  const SCEV *MaxBECount = computeMaxBECountForLT(
      Start, Stride, RHS, getTypeSizeInBits(LHS->getType()), IsSigned);
  return ExitLimit(getCouldNotCompute() /* ExactNotTaken */, MaxBECount,
                   false /*MaxOrZero*/, Predicates);
}
// If the backedge is taken at least once, then it will be taken
// (End-Start)/Stride times (rounded up to a multiple of Stride), where Start
// is the LHS value of the less-than comparison the first time it is evaluated
// and End is the RHS.
const SCEV *BECountIfBackedgeTaken =
  computeBECount(getMinusSCEV(End, Start), Stride, false);
// If the loop entry is guarded by the result of the backedge test of the
// first loop iteration, then we know the backedge will be taken at least
// once and so the backedge taken count is as above. If not then we use the
// expression (max(End,Start)-Start)/Stride to describe the backedge count,
// as if the backedge is taken at least once max(End,Start) is End and so the
// result is as above, and if not max(End,Start) is Start so we get a backedge
// count of zero.
const SCEV *BECount;
if (isLoopEntryGuardedByCond(L, Cond, getMinusSCEV(Start, Stride), RHS))
  BECount = BECountIfBackedgeTaken;
else {
  // If we know that RHS >= Start in the context of loop, then we know that
  // max(RHS, Start) = RHS at this point.
  if (isLoopEntryGuardedByCond(
          L, IsSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE, RHS, Start))
    End = RHS;
  else
    End = IsSigned ? getSMaxExpr(RHS, Start) : getUMaxExpr(RHS, Start);
  BECount = computeBECount(getMinusSCEV(End, Start), Stride, false);
}

const SCEV *MaxBECount;
bool MaxOrZero = false;
if (isa<SCEVConstant>(BECount))
  MaxBECount = BECount;
else if (isa<SCEVConstant>(BECountIfBackedgeTaken)) {
  // If we know exactly how many times the backedge will be taken if it's
  // taken at least once, then the backedge count will either be that or
  // zero.
  MaxBECount = BECountIfBackedgeTaken;
  MaxOrZero = true;
} else {
  MaxBECount = computeMaxBECountForLT(
      Start, Stride, RHS, getTypeSizeInBits(LHS->getType()), IsSigned);
}

if (isa<SCEVCouldNotCompute>(MaxBECount) &&
    !isa<SCEVCouldNotCompute>(BECount))
  MaxBECount = getConstant(getUnsignedRangeMax(BECount));

return ExitLimit(BECount, MaxBECount, MaxOrZero, Predicates);
11248}

11250ScalarEvolution::ExitLimit
11251ScalarEvolution::howManyGreaterThans(const SCEV *LHS, const SCEV *RHS,
                                   const Loop *L, bool IsSigned,
                                   bool ControlsExit, bool AllowPredicates) {
SmallPtrSet<const SCEVPredicate *, 4> Predicates;
// We handle only IV > Invariant
if (!isLoopInvariant(RHS, L))
  return getCouldNotCompute();

const SCEVAddRecExpr *IV = dyn_cast<SCEVAddRecExpr>(LHS);
if (!IV && AllowPredicates)
  // Try to make this an AddRec using runtime tests, in the first X
  // iterations of this loop, where X is the SCEV expression found by the
  // algorithm below.
  IV = convertSCEVToAddRecWithPredicates(LHS, L, Predicates);

// Avoid weird loops
if (!IV || IV->getLoop() != L || !IV->isAffine())
  return getCouldNotCompute();

bool NoWrap = ControlsExit &&
              IV->getNoWrapFlags(IsSigned ? SCEV::FlagNSW : SCEV::FlagNUW);

const SCEV *Stride = getNegativeSCEV(IV->getStepRecurrence(*this));

// Avoid negative or zero stride values
if (!isKnownPositive(Stride))
  return getCouldNotCompute();

// Avoid proven overflow cases: this will ensure that the backedge taken count
// will not generate any unsigned overflow. Relaxed no-overflow conditions
// exploit NoWrapFlags, allowing to optimize in presence of undefined
// behaviors like the case of C language.
if (!Stride->isOne() && doesIVOverflowOnGT(RHS, Stride, IsSigned, NoWrap))
  return getCouldNotCompute();

ICmpInst::Predicate Cond = IsSigned ? ICmpInst::ICMP_SGT
                                    : ICmpInst::ICMP_UGT;

const SCEV *Start = IV->getStart();
const SCEV *End = RHS;
if (!isLoopEntryGuardedByCond(L, Cond, getAddExpr(Start, Stride), RHS)) {
  // If we know that Start >= RHS in the context of loop, then we know that
  // min(RHS, Start) = RHS at this point.
  if (isLoopEntryGuardedByCond(
          L, IsSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE, Start, RHS))
    End = RHS;
  else
    End = IsSigned ? getSMinExpr(RHS, Start) : getUMinExpr(RHS, Start);
}

const SCEV *BECount = computeBECount(getMinusSCEV(Start, End), Stride, false);

APInt MaxStart = IsSigned ? getSignedRangeMax(Start)
                          : getUnsignedRangeMax(Start);

APInt MinStride = IsSigned ? getSignedRangeMin(Stride)
                           : getUnsignedRangeMin(Stride);

unsigned BitWidth = getTypeSizeInBits(LHS->getType());
APInt Limit = IsSigned ? APInt::getSignedMinValue(BitWidth) + (MinStride - 1)
                       : APInt::getMinValue(BitWidth) + (MinStride - 1);

// Although End can be a MIN expression we estimate MinEnd considering only
// the case End = RHS. This is safe because in the other case (Start - End)
// is zero, leading to a zero maximum backedge taken count.
APInt MinEnd =
  IsSigned ? APIntOps::smax(getSignedRangeMin(RHS), Limit)
           : APIntOps::umax(getUnsignedRangeMin(RHS), Limit);

const SCEV *MaxBECount = isa<SCEVConstant>(BECount)
                             ? BECount
                             : computeBECount(getConstant(MaxStart - MinEnd),
                                              getConstant(MinStride), false);

if (isa<SCEVCouldNotCompute>(MaxBECount))
  MaxBECount = BECount;

return ExitLimit(BECount, MaxBECount, false, Predicates);
11329}

11331const SCEV *SCEVAddRecExpr::getNumIterationsInRange(const ConstantRange &Range,
                                                  ScalarEvolution &SE) const {
if (Range.isFullSet())  // Infinite loop.
  return SE.getCouldNotCompute();

// If the start is a non-zero constant, shift the range to simplify things.
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(getStart()))
  if (!SC->getValue()->isZero()) {
    SmallVector<const SCEV *, 4> Operands(op_begin(), op_end());
    Operands[0] = SE.getZero(SC->getType());
    const SCEV *Shifted = SE.getAddRecExpr(Operands, getLoop(),
                                           getNoWrapFlags(FlagNW));
    if (const auto *ShiftedAddRec = dyn_cast<SCEVAddRecExpr>(Shifted))
      return ShiftedAddRec->getNumIterationsInRange(
          Range.subtract(SC->getAPInt()), SE);
    // This is strange and shouldn't happen.
    return SE.getCouldNotCompute();
  }

// The only time we can solve this is when we have all constant indices.
// Otherwise, we cannot determine the overflow conditions.
if (any_of(operands(), [](const SCEV *Op) { return !isa<SCEVConstant>(Op); }))
  return SE.getCouldNotCompute();

// Okay at this point we know that all elements of the chrec are constants and
// that the start element is zero.

// First check to see if the range contains zero.  If not, the first
// iteration exits.
unsigned BitWidth = SE.getTypeSizeInBits(getType());
if (!Range.contains(APInt(BitWidth, 0)))
  return SE.getZero(getType());

if (isAffine()) {
  // If this is an affine expression then we have this situation:
  //   Solve {0,+,A} in Range  ===  Ax in Range

  // We know that zero is in the range.  If A is positive then we know that
  // the upper value of the range must be the first possible exit value.
  // If A is negative then the lower of the range is the last possible loop
  // value.  Also note that we already checked for a full range.
  APInt A = cast<SCEVConstant>(getOperand(1))->getAPInt();
  APInt End = A.sge(1) ? (Range.getUpper() - 1) : Range.getLower();

  // The exit value should be (End+A)/A.
  APInt ExitVal = (End + A).udiv(A);
  ConstantInt *ExitValue = ConstantInt::get(SE.getContext(), ExitVal);

  // Evaluate at the exit value.  If we really did fall out of the valid
  // range, then we computed our trip count, otherwise wrap around or other
  // things must have happened.
  ConstantInt *Val = EvaluateConstantChrecAtConstant(this, ExitValue, SE);
  if (Range.contains(Val->getValue()))
    return SE.getCouldNotCompute();  // Something strange happened

  // Ensure that the previous value is in the range.  This is a sanity check.
  assert(Range.contains(((Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt
::get(SE.getContext(), ExitVal - 1), SE)->getValue()) &&
 "Linear scev computation is off in a bad way!") ? static_cast
<void> (0) : __assert_fail ("Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && \"Linear scev computation is off in a bad way!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11390, __PRETTY_FUNCTION__))
         EvaluateConstantChrecAtConstant(this,((Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt
::get(SE.getContext(), ExitVal - 1), SE)->getValue()) &&
 "Linear scev computation is off in a bad way!") ? static_cast
<void> (0) : __assert_fail ("Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && \"Linear scev computation is off in a bad way!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11390, __PRETTY_FUNCTION__))
         ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) &&((Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt
::get(SE.getContext(), ExitVal - 1), SE)->getValue()) &&
 "Linear scev computation is off in a bad way!") ? static_cast
<void> (0) : __assert_fail ("Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && \"Linear scev computation is off in a bad way!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11390, __PRETTY_FUNCTION__))
         "Linear scev computation is off in a bad way!")((Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt
::get(SE.getContext(), ExitVal - 1), SE)->getValue()) &&
 "Linear scev computation is off in a bad way!") ? static_cast
<void> (0) : __assert_fail ("Range.contains( EvaluateConstantChrecAtConstant(this, ConstantInt::get(SE.getContext(), ExitVal - 1), SE)->getValue()) && \"Linear scev computation is off in a bad way!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11390, __PRETTY_FUNCTION__));
  return SE.getConstant(ExitValue);
}

if (isQuadratic()) {
  if (auto S = SolveQuadraticAddRecRange(this, Range, SE))
    return SE.getConstant(S.getValue());
}

return SE.getCouldNotCompute();
11400}

11402const SCEVAddRecExpr *
11403SCEVAddRecExpr::getPostIncExpr(ScalarEvolution &SE) const {
assert(getNumOperands() > 1 && "AddRec with zero step?")((getNumOperands() > 1 && "AddRec with zero step?"
) ? static_cast<void> (0) : __assert_fail ("getNumOperands() > 1 && \"AddRec with zero step?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11404, __PRETTY_FUNCTION__));
// There is a temptation to just call getAddExpr(this, getStepRecurrence(SE)),
// but in this case we cannot guarantee that the value returned will be an
// AddRec because SCEV does not have a fixed point where it stops
// simplification: it is legal to return ({rec1} + {rec2}). For example, it
// may happen if we reach arithmetic depth limit while simplifying. So we
// construct the returned value explicitly.
SmallVector<const SCEV *, 3> Ops;
// If this is {A,+,B,+,C,...,+,N}, then its step is {B,+,C,+,...,+,N}, and
// (this + Step) is {A+B,+,B+C,+...,+,N}.
for (unsigned i = 0, e = getNumOperands() - 1; i < e; ++i)
  Ops.push_back(SE.getAddExpr(getOperand(i), getOperand(i + 1)));
// We know that the last operand is not a constant zero (otherwise it would
// have been popped out earlier). This guarantees us that if the result has
// the same last operand, then it will also not be popped out, meaning that
// the returned value will be an AddRec.
const SCEV *Last = getOperand(getNumOperands() - 1);
assert(!Last->isZero() && "Recurrency with zero step?")((!Last->isZero() && "Recurrency with zero step?")
 ? static_cast<void> (0) : __assert_fail ("!Last->isZero() && \"Recurrency with zero step?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11421, __PRETTY_FUNCTION__));
Ops.push_back(Last);
return cast<SCEVAddRecExpr>(SE.getAddRecExpr(Ops, getLoop(),
                                             SCEV::FlagAnyWrap));
11425}

11427// Return true when S contains at least an undef value.
11428static inline bool containsUndefs(const SCEV *S) {
return SCEVExprContains(S, [](const SCEV *S) {
  if (const auto *SU = dyn_cast<SCEVUnknown>(S))
    return isa<UndefValue>(SU->getValue());
  return false;
});
11434}

11436namespace {

11438// Collect all steps of SCEV expressions.
11439struct SCEVCollectStrides {
ScalarEvolution &SE;
SmallVectorImpl<const SCEV *> &Strides;

SCEVCollectStrides(ScalarEvolution &SE, SmallVectorImpl<const SCEV *> &S)
    : SE(SE), Strides(S) {}

bool follow(const SCEV *S) {
  if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S))
    Strides.push_back(AR->getStepRecurrence(SE));
  return true;
}

bool isDone() const { return false; }
11453};

11455// Collect all SCEVUnknown and SCEVMulExpr expressions.
11456struct SCEVCollectTerms {
SmallVectorImpl<const SCEV *> &Terms;

SCEVCollectTerms(SmallVectorImpl<const SCEV *> &T) : Terms(T) {}

bool follow(const SCEV *S) {
  if (isa<SCEVUnknown>(S) || isa<SCEVMulExpr>(S) ||
      isa<SCEVSignExtendExpr>(S)) {
    if (!containsUndefs(S))
      Terms.push_back(S);

    // Stop recursion: once we collected a term, do not walk its operands.
    return false;
  }

  // Keep looking.
  return true;
}

bool isDone() const { return false; }
11476};

11478// Check if a SCEV contains an AddRecExpr.
11479struct SCEVHasAddRec {
bool &ContainsAddRec;

SCEVHasAddRec(bool &ContainsAddRec) : ContainsAddRec(ContainsAddRec) {
  ContainsAddRec = false;
}

bool follow(const SCEV *S) {
  if (isa<SCEVAddRecExpr>(S)) {
    ContainsAddRec = true;

    // Stop recursion: once we collected a term, do not walk its operands.
    return false;
  }

  // Keep looking.
  return true;
}

bool isDone() const { return false; }
11499};

11501// Find factors that are multiplied with an expression that (possibly as a
11502// subexpression) contains an AddRecExpr. In the expression:
11503//
11504//  8 * (100 +  %p * %q * (%a + {0, +, 1}_loop))
11505//
11506// "%p * %q" are factors multiplied by the expression "(%a + {0, +, 1}_loop)"
11507// that contains the AddRec {0, +, 1}_loop. %p * %q are likely to be array size
11508// parameters as they form a product with an induction variable.
11509//
11510// This collector expects all array size parameters to be in the same MulExpr.
11511// It might be necessary to later add support for collecting parameters that are
11512// spread over different nested MulExpr.
11513struct SCEVCollectAddRecMultiplies {
SmallVectorImpl<const SCEV *> &Terms;
ScalarEvolution &SE;

SCEVCollectAddRecMultiplies(SmallVectorImpl<const SCEV *> &T, ScalarEvolution &SE)
    : Terms(T), SE(SE) {}

bool follow(const SCEV *S) {
  if (auto *Mul = dyn_cast<SCEVMulExpr>(S)) {
    bool HasAddRec = false;
    SmallVector<const SCEV *, 0> Operands;
    for (auto Op : Mul->operands()) {
      const SCEVUnknown *Unknown = dyn_cast<SCEVUnknown>(Op);
      if (Unknown && !isa<CallInst>(Unknown->getValue())) {
        Operands.push_back(Op);
      } else if (Unknown) {
        HasAddRec = true;
      } else {
        bool ContainsAddRec = false;
        SCEVHasAddRec ContiansAddRec(ContainsAddRec);
        visitAll(Op, ContiansAddRec);
        HasAddRec |= ContainsAddRec;
      }
    }
    if (Operands.size() == 0)
      return true;

    if (!HasAddRec)
      return false;

    Terms.push_back(SE.getMulExpr(Operands));
    // Stop recursion: once we collected a term, do not walk its operands.
    return false;
  }

  // Keep looking.
  return true;
}

bool isDone() const { return false; }
11553};

11555} // end anonymous namespace

11557/// Find parametric terms in this SCEVAddRecExpr. We first for parameters in
11558/// two places:
11559///   1) The strides of AddRec expressions.
11560///   2) Unknowns that are multiplied with AddRec expressions.
11561void ScalarEvolution::collectParametricTerms(const SCEV *Expr,
  SmallVectorImpl<const SCEV *> &Terms) {
SmallVector<const SCEV *, 4> Strides;
SCEVCollectStrides StrideCollector(*this, Strides);
visitAll(Expr, StrideCollector);

LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Strides:\n"; for (
const SCEV *S : Strides) dbgs() << *S << "\n"; };
 } } while (false)
  dbgs() << "Strides:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Strides:\n"; for (
const SCEV *S : Strides) dbgs() << *S << "\n"; };
 } } while (false)
  for (const SCEV *S : Strides)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Strides:\n"; for (
const SCEV *S : Strides) dbgs() << *S << "\n"; };
 } } while (false)
    dbgs() << *S << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Strides:\n"; for (
const SCEV *S : Strides) dbgs() << *S << "\n"; };
 } } while (false)
})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Strides:\n"; for (
const SCEV *S : Strides) dbgs() << *S << "\n"; };
 } } while (false);

for (const SCEV *S : Strides) {
  SCEVCollectTerms TermCollector(Terms);
  visitAll(S, TermCollector);
}

LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const
 SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while
 (false)
  dbgs() << "Terms:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const
 SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while
 (false)
  for (const SCEV *T : Terms)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const
 SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while
 (false)
    dbgs() << *T << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const
 SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while
 (false)
})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const
 SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while
 (false);

SCEVCollectAddRecMultiplies MulCollector(Terms, *this);
visitAll(Expr, MulCollector);
11586}

11588static bool findArrayDimensionsRec(ScalarEvolution &SE,
                                 SmallVectorImpl<const SCEV *> &Terms,
                                 SmallVectorImpl<const SCEV *> &Sizes) {
int Last = Terms.size() - 1;
const SCEV *Step = Terms[Last];

// End of recursion.
if (Last == 0) {
  if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(Step)) {
    SmallVector<const SCEV *, 2> Qs;
    for (const SCEV *Op : M->operands())
      if (!isa<SCEVConstant>(Op))
        Qs.push_back(Op);

    Step = SE.getMulExpr(Qs);
  }

  Sizes.push_back(Step);
  return true;
}

for (const SCEV *&Term : Terms) {
  // Normalize the terms before the next call to findArrayDimensionsRec.
  const SCEV *Q, *R;
  SCEVDivision::divide(SE, Term, Step, &Q, &R);

  // Bail out when GCD does not evenly divide one of the terms.
  if (!R->isZero())
    return false;

  Term = Q;
}

// Remove all SCEVConstants.
Terms.erase(
    remove_if(Terms, [](const SCEV *E) { return isa<SCEVConstant>(E); }),
    Terms.end());

if (Terms.size() > 0)
  if (!findArrayDimensionsRec(SE, Terms, Sizes))
    return false;

Sizes.push_back(Step);
return true;
11632}

11634// Returns true when one of the SCEVs of Terms contains a SCEVUnknown parameter.
11635static inline bool containsParameters(SmallVectorImpl<const SCEV *> &Terms) {
for (const SCEV *T : Terms)
  if (SCEVExprContains(T, [](const SCEV *S) { return isa<SCEVUnknown>(S); }))
    return true;

return false;
11641}

11643// Return the number of product terms in S.
11644static inline int numberOfTerms(const SCEV *S) {
if (const SCEVMulExpr *Expr = dyn_cast<SCEVMulExpr>(S))
  return Expr->getNumOperands();
return 1;
11648}

11650static const SCEV *removeConstantFactors(ScalarEvolution &SE, const SCEV *T) {
if (isa<SCEVConstant>(T))
  return nullptr;

if (isa<SCEVUnknown>(T))
  return T;

if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(T)) {
  SmallVector<const SCEV *, 2> Factors;
  for (const SCEV *Op : M->operands())
    if (!isa<SCEVConstant>(Op))
      Factors.push_back(Op);

  return SE.getMulExpr(Factors);
}

return T;
11667}

11669/// Return the size of an element read or written by Inst.
11670const SCEV *ScalarEvolution::getElementSize(Instruction *Inst) {
Type *Ty;
if (StoreInst *Store = dyn_cast<StoreInst>(Inst))
  Ty = Store->getValueOperand()->getType();
else if (LoadInst *Load = dyn_cast<LoadInst>(Inst))
  Ty = Load->getType();
else
  return nullptr;

Type *ETy = getEffectiveSCEVType(PointerType::getUnqual(Ty));
return getSizeOfExpr(ETy, Ty);
11681}

11683void ScalarEvolution::findArrayDimensions(SmallVectorImpl<const SCEV *> &Terms,
                                        SmallVectorImpl<const SCEV *> &Sizes,
                                        const SCEV *ElementSize) {
if (Terms.size() < 1 || !ElementSize)
  return;

// Early return when Terms do not contain parameters: we do not delinearize
// non parametric SCEVs.
if (!containsParameters(Terms))
  return;

LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const
 SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while
 (false)
  dbgs() << "Terms:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const
 SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while
 (false)
  for (const SCEV *T : Terms)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const
 SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while
 (false)
    dbgs() << *T << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const
 SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while
 (false)
})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms:\n"; for (const
 SCEV *T : Terms) dbgs() << *T << "\n"; }; } } while
 (false);

// Remove duplicates.
array_pod_sort(Terms.begin(), Terms.end());
Terms.erase(std::unique(Terms.begin(), Terms.end()), Terms.end());

// Put larger terms first.
llvm::sort(Terms, [](const SCEV *LHS, const SCEV *RHS) {
  return numberOfTerms(LHS) > numberOfTerms(RHS);
});

// Try to divide all terms by the element size. If term is not divisible by
// element size, proceed with the original term.
for (const SCEV *&Term : Terms) {
  const SCEV *Q, *R;
  SCEVDivision::divide(*this, Term, ElementSize, &Q, &R);
  if (!Q->isZero())
    Term = Q;
}

SmallVector<const SCEV *, 4> NewTerms;

// Remove constant factors.
for (const SCEV *T : Terms)
  if (const SCEV *NewT = removeConstantFactors(*this, T))
    NewTerms.push_back(NewT);

LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms after sorting:\n"
; for (const SCEV *T : NewTerms) dbgs() << *T << "\n"
; }; } } while (false)
  dbgs() << "Terms after sorting:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms after sorting:\n"
; for (const SCEV *T : NewTerms) dbgs() << *T << "\n"
; }; } } while (false)
  for (const SCEV *T : NewTerms)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms after sorting:\n"
; for (const SCEV *T : NewTerms) dbgs() << *T << "\n"
; }; } } while (false)
    dbgs() << *T << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms after sorting:\n"
; for (const SCEV *T : NewTerms) dbgs() << *T << "\n"
; }; } } while (false)
})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Terms after sorting:\n"
; for (const SCEV *T : NewTerms) dbgs() << *T << "\n"
; }; } } while (false);

if (NewTerms.empty() || !findArrayDimensionsRec(*this, NewTerms, Sizes)) {
  Sizes.clear();
  return;
}

// The last element to be pushed into Sizes is the size of an element.
Sizes.push_back(ElementSize);

LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Sizes:\n"; for (const
 SCEV *S : Sizes) dbgs() << *S << "\n"; }; } } while
 (false)
  dbgs() << "Sizes:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Sizes:\n"; for (const
 SCEV *S : Sizes) dbgs() << *S << "\n"; }; } } while
 (false)
  for (const SCEV *S : Sizes)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Sizes:\n"; for (const
 SCEV *S : Sizes) dbgs() << *S << "\n"; }; } } while
 (false)
    dbgs() << *S << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Sizes:\n"; for (const
 SCEV *S : Sizes) dbgs() << *S << "\n"; }; } } while
 (false)
})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Sizes:\n"; for (const
 SCEV *S : Sizes) dbgs() << *S << "\n"; }; } } while
 (false);
11744}

11746void ScalarEvolution::computeAccessFunctions(
  const SCEV *Expr, SmallVectorImpl<const SCEV *> &Subscripts,
  SmallVectorImpl<const SCEV *> &Sizes) {
// Early exit in case this SCEV is not an affine multivariate function.
if (Sizes.empty())
  return;

if (auto *AR = dyn_cast<SCEVAddRecExpr>(Expr))
  if (!AR->isAffine())
    return;

const SCEV *Res = Expr;
int Last = Sizes.size() - 1;
for (int i = Last; i >= 0; i--) {
  const SCEV *Q, *R;
  SCEVDivision::divide(*this, Res, Sizes[i], &Q, &R);

  LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Res: " << *Res
 << "\n"; dbgs() << "Sizes[i]: " << *Sizes[
i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n"
; dbgs() << "Quotient: " << *Q << "\n"; dbgs
() << "Remainder: " << *R << "\n"; }; } } while
 (false)
    dbgs() << "Res: " << *Res << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Res: " << *Res
 << "\n"; dbgs() << "Sizes[i]: " << *Sizes[
i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n"
; dbgs() << "Quotient: " << *Q << "\n"; dbgs
() << "Remainder: " << *R << "\n"; }; } } while
 (false)
    dbgs() << "Sizes[i]: " << *Sizes[i] << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Res: " << *Res
 << "\n"; dbgs() << "Sizes[i]: " << *Sizes[
i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n"
; dbgs() << "Quotient: " << *Q << "\n"; dbgs
() << "Remainder: " << *R << "\n"; }; } } while
 (false)
    dbgs() << "Res divided by Sizes[i]:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Res: " << *Res
 << "\n"; dbgs() << "Sizes[i]: " << *Sizes[
i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n"
; dbgs() << "Quotient: " << *Q << "\n"; dbgs
() << "Remainder: " << *R << "\n"; }; } } while
 (false)
    dbgs() << "Quotient: " << *Q << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Res: " << *Res
 << "\n"; dbgs() << "Sizes[i]: " << *Sizes[
i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n"
; dbgs() << "Quotient: " << *Q << "\n"; dbgs
() << "Remainder: " << *R << "\n"; }; } } while
 (false)
    dbgs() << "Remainder: " << *R << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Res: " << *Res
 << "\n"; dbgs() << "Sizes[i]: " << *Sizes[
i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n"
; dbgs() << "Quotient: " << *Q << "\n"; dbgs
() << "Remainder: " << *R << "\n"; }; } } while
 (false)
  })do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Res: " << *Res
 << "\n"; dbgs() << "Sizes[i]: " << *Sizes[
i] << "\n"; dbgs() << "Res divided by Sizes[i]:\n"
; dbgs() << "Quotient: " << *Q << "\n"; dbgs
() << "Remainder: " << *R << "\n"; }; } } while
 (false);

  Res = Q;

  // Do not record the last subscript corresponding to the size of elements in
  // the array.
  if (i == Last) {

    // Bail out if the remainder is too complex.
    if (isa<SCEVAddRecExpr>(R)) {
      Subscripts.clear();
      Sizes.clear();
      return;
    }

    continue;
  }

  // Record the access function for the current subscript.
  Subscripts.push_back(R);
}

// Also push in last position the remainder of the last division: it will be
// the access function of the innermost dimension.
Subscripts.push_back(Res);

std::reverse(Subscripts.begin(), Subscripts.end());

LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Subscripts:\n"; for
 (const SCEV *S : Subscripts) dbgs() << *S << "\n"
; }; } } while (false)
  dbgs() << "Subscripts:\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Subscripts:\n"; for
 (const SCEV *S : Subscripts) dbgs() << *S << "\n"
; }; } } while (false)
  for (const SCEV *S : Subscripts)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Subscripts:\n"; for
 (const SCEV *S : Subscripts) dbgs() << *S << "\n"
; }; } } while (false)
    dbgs() << *S << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Subscripts:\n"; for
 (const SCEV *S : Subscripts) dbgs() << *S << "\n"
; }; } } while (false)
})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "Subscripts:\n"; for
 (const SCEV *S : Subscripts) dbgs() << *S << "\n"
; }; } } while (false);
11802}

11804/// Splits the SCEV into two vectors of SCEVs representing the subscripts and
11805/// sizes of an array access. Returns the remainder of the delinearization that
11806/// is the offset start of the array.  The SCEV->delinearize algorithm computes
11807/// the multiples of SCEV coefficients: that is a pattern matching of sub
11808/// expressions in the stride and base of a SCEV corresponding to the
11809/// computation of a GCD (greatest common divisor) of base and stride.  When
11810/// SCEV->delinearize fails, it returns the SCEV unchanged.
11811///
11812/// For example: when analyzing the memory access A[i][j][k] in this loop nest
11813///
11814///  void foo(long n, long m, long o, double A[n][m][o]) {
11815///
11816///    for (long i = 0; i < n; i++)
11817///      for (long j = 0; j < m; j++)
11818///        for (long k = 0; k < o; k++)
11819///          A[i][j][k] = 1.0;
11820///  }
11821///
11822/// the delinearization input is the following AddRec SCEV:
11823///
11824///  AddRec: {{{%A,+,(8 * %m * %o)}<%for.i>,+,(8 * %o)}<%for.j>,+,8}<%for.k>
11825///
11826/// From this SCEV, we are able to say that the base offset of the access is %A
11827/// because it appears as an offset that does not divide any of the strides in
11828/// the loops:
11829///
11830///  CHECK: Base offset: %A
11831///
11832/// and then SCEV->delinearize determines the size of some of the dimensions of
11833/// the array as these are the multiples by which the strides are happening:
11834///
11835///  CHECK: ArrayDecl[UnknownSize][%m][%o] with elements of sizeof(double) bytes.
11836///
11837/// Note that the outermost dimension remains of UnknownSize because there are
11838/// no strides that would help identifying the size of the last dimension: when
11839/// the array has been statically allocated, one could compute the size of that
11840/// dimension by dividing the overall size of the array by the size of the known
11841/// dimensions: %m * %o * 8.
11842///
11843/// Finally delinearize provides the access functions for the array reference
11844/// that does correspond to A[i][j][k] of the above C testcase:
11845///
11846///  CHECK: ArrayRef[{0,+,1}<%for.i>][{0,+,1}<%for.j>][{0,+,1}<%for.k>]
11847///
11848/// The testcases are checking the output of a function pass:
11849/// DelinearizationPass that walks through all loads and stores of a function
11850/// asking for the SCEV of the memory access with respect to all enclosing
11851/// loops, calling SCEV->delinearize on that and printing the results.
11852void ScalarEvolution::delinearize(const SCEV *Expr,
                               SmallVectorImpl<const SCEV *> &Subscripts,
                               SmallVectorImpl<const SCEV *> &Sizes,
                               const SCEV *ElementSize) {
// First step: collect parametric terms.
SmallVector<const SCEV *, 4> Terms;
collectParametricTerms(Expr, Terms);

if (Terms.empty())
  return;

// Second step: find subscript sizes.
findArrayDimensions(Terms, Sizes, ElementSize);

if (Sizes.empty())
  return;

// Third step: compute the access functions for each subscript.
computeAccessFunctions(Expr, Subscripts, Sizes);

if (Subscripts.empty())
  return;

LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "succeeded to delinearize "
 << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]"
; for (const SCEV *S : Sizes) dbgs() << "[" << *S
 << "]"; dbgs() << "\nArrayRef"; for (const SCEV *
S : Subscripts) dbgs() << "[" << *S << "]";
 dbgs() << "\n"; }; } } while (false)
  dbgs() << "succeeded to delinearize " << *Expr << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "succeeded to delinearize "
 << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]"
; for (const SCEV *S : Sizes) dbgs() << "[" << *S
 << "]"; dbgs() << "\nArrayRef"; for (const SCEV *
S : Subscripts) dbgs() << "[" << *S << "]";
 dbgs() << "\n"; }; } } while (false)
  dbgs() << "ArrayDecl[UnknownSize]";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "succeeded to delinearize "
 << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]"
; for (const SCEV *S : Sizes) dbgs() << "[" << *S
 << "]"; dbgs() << "\nArrayRef"; for (const SCEV *
S : Subscripts) dbgs() << "[" << *S << "]";
 dbgs() << "\n"; }; } } while (false)
  for (const SCEV *S : Sizes)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "succeeded to delinearize "
 << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]"
; for (const SCEV *S : Sizes) dbgs() << "[" << *S
 << "]"; dbgs() << "\nArrayRef"; for (const SCEV *
S : Subscripts) dbgs() << "[" << *S << "]";
 dbgs() << "\n"; }; } } while (false)
    dbgs() << "[" << *S << "]";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "succeeded to delinearize "
 << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]"
; for (const SCEV *S : Sizes) dbgs() << "[" << *S
 << "]"; dbgs() << "\nArrayRef"; for (const SCEV *
S : Subscripts) dbgs() << "[" << *S << "]";
 dbgs() << "\n"; }; } } while (false)

  dbgs() << "\nArrayRef";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "succeeded to delinearize "
 << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]"
; for (const SCEV *S : Sizes) dbgs() << "[" << *S
 << "]"; dbgs() << "\nArrayRef"; for (const SCEV *
S : Subscripts) dbgs() << "[" << *S << "]";
 dbgs() << "\n"; }; } } while (false)
  for (const SCEV *S : Subscripts)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "succeeded to delinearize "
 << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]"
; for (const SCEV *S : Sizes) dbgs() << "[" << *S
 << "]"; dbgs() << "\nArrayRef"; for (const SCEV *
S : Subscripts) dbgs() << "[" << *S << "]";
 dbgs() << "\n"; }; } } while (false)
    dbgs() << "[" << *S << "]";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "succeeded to delinearize "
 << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]"
; for (const SCEV *S : Sizes) dbgs() << "[" << *S
 << "]"; dbgs() << "\nArrayRef"; for (const SCEV *
S : Subscripts) dbgs() << "[" << *S << "]";
 dbgs() << "\n"; }; } } while (false)
  dbgs() << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "succeeded to delinearize "
 << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]"
; for (const SCEV *S : Sizes) dbgs() << "[" << *S
 << "]"; dbgs() << "\nArrayRef"; for (const SCEV *
S : Subscripts) dbgs() << "[" << *S << "]";
 dbgs() << "\n"; }; } } while (false)
})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("scalar-evolution")) { { dbgs() << "succeeded to delinearize "
 << *Expr << "\n"; dbgs() << "ArrayDecl[UnknownSize]"
; for (const SCEV *S : Sizes) dbgs() << "[" << *S
 << "]"; dbgs() << "\nArrayRef"; for (const SCEV *
S : Subscripts) dbgs() << "[" << *S << "]";
 dbgs() << "\n"; }; } } while (false);
11886}

11888bool ScalarEvolution::getIndexExpressionsFromGEP(
  const GetElementPtrInst *GEP, SmallVectorImpl<const SCEV *> &Subscripts,
  SmallVectorImpl<int> &Sizes) {
assert(Subscripts.empty() && Sizes.empty() &&((Subscripts.empty() && Sizes.empty() && "Expected output lists to be empty on entry to this function."
) ? static_cast<void> (0) : __assert_fail ("Subscripts.empty() && Sizes.empty() && \"Expected output lists to be empty on entry to this function.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11892, __PRETTY_FUNCTION__))
       "Expected output lists to be empty on entry to this function.")((Subscripts.empty() && Sizes.empty() && "Expected output lists to be empty on entry to this function."
) ? static_cast<void> (0) : __assert_fail ("Subscripts.empty() && Sizes.empty() && \"Expected output lists to be empty on entry to this function.\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11892, __PRETTY_FUNCTION__));
assert(GEP && "getIndexExpressionsFromGEP called with a null GEP")((GEP && "getIndexExpressionsFromGEP called with a null GEP"
) ? static_cast<void> (0) : __assert_fail ("GEP && \"getIndexExpressionsFromGEP called with a null GEP\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11893, __PRETTY_FUNCTION__));
Type *Ty = GEP->getPointerOperandType();
bool DroppedFirstDim = false;
for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
  const SCEV *Expr = getSCEV(GEP->getOperand(i));
  if (i == 1) {
    if (auto *PtrTy = dyn_cast<PointerType>(Ty)) {
      Ty = PtrTy->getElementType();
    } else if (auto *ArrayTy = dyn_cast<ArrayType>(Ty)) {
      Ty = ArrayTy->getElementType();
    } else {
      Subscripts.clear();
      Sizes.clear();
      return false;
    }
    if (auto *Const = dyn_cast<SCEVConstant>(Expr))
      if (Const->getValue()->isZero()) {
        DroppedFirstDim = true;
        continue;
      }
    Subscripts.push_back(Expr);
    continue;
  }

  auto *ArrayTy = dyn_cast<ArrayType>(Ty);
  if (!ArrayTy) {
    Subscripts.clear();
    Sizes.clear();
    return false;
  }

  Subscripts.push_back(Expr);
  if (!(DroppedFirstDim && i == 2))
    Sizes.push_back(ArrayTy->getNumElements());

  Ty = ArrayTy->getElementType();
}
return !Subscripts.empty();
11931}

11933//===----------------------------------------------------------------------===//
11934//                   SCEVCallbackVH Class Implementation
11935//===----------------------------------------------------------------------===//

11937void ScalarEvolution::SCEVCallbackVH::deleted() {
assert(SE && "SCEVCallbackVH called with a null ScalarEvolution!")((SE && "SCEVCallbackVH called with a null ScalarEvolution!"
) ? static_cast<void> (0) : __assert_fail ("SE && \"SCEVCallbackVH called with a null ScalarEvolution!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11938, __PRETTY_FUNCTION__));
if (PHINode *PN = dyn_cast<PHINode>(getValPtr()))
  SE->ConstantEvolutionLoopExitValue.erase(PN);
SE->eraseValueFromMap(getValPtr());
// this now dangles!
11943}

11945void ScalarEvolution::SCEVCallbackVH::allUsesReplacedWith(Value *V) {
assert(SE && "SCEVCallbackVH called with a null ScalarEvolution!")((SE && "SCEVCallbackVH called with a null ScalarEvolution!"
) ? static_cast<void> (0) : __assert_fail ("SE && \"SCEVCallbackVH called with a null ScalarEvolution!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 11946, __PRETTY_FUNCTION__));

// Forget all the expressions associated with users of the old value,
// so that future queries will recompute the expressions using the new
// value.
Value *Old = getValPtr();
SmallVector<User *, 16> Worklist(Old->user_begin(), Old->user_end());
SmallPtrSet<User *, 8> Visited;
while (!Worklist.empty()) {
  User *U = Worklist.pop_back_val();
  // Deleting the Old value will cause this to dangle. Postpone
  // that until everything else is done.
  if (U == Old)
    continue;
  if (!Visited.insert(U).second)
    continue;
  if (PHINode *PN = dyn_cast<PHINode>(U))
    SE->ConstantEvolutionLoopExitValue.erase(PN);
  SE->eraseValueFromMap(U);
  Worklist.insert(Worklist.end(), U->user_begin(), U->user_end());
}
// Delete the Old value.
if (PHINode *PN = dyn_cast<PHINode>(Old))
  SE->ConstantEvolutionLoopExitValue.erase(PN);
SE->eraseValueFromMap(Old);
// this now dangles!
11972}

11974ScalarEvolution::SCEVCallbackVH::SCEVCallbackVH(Value *V, ScalarEvolution *se)
: CallbackVH(V), SE(se) {}

11977//===----------------------------------------------------------------------===//
11978//                   ScalarEvolution Class Implementation
11979//===----------------------------------------------------------------------===//

11981ScalarEvolution::ScalarEvolution(Function &F, TargetLibraryInfo &TLI,
                               AssumptionCache &AC, DominatorTree &DT,
                               LoopInfo &LI)
  : F(F), TLI(TLI), AC(AC), DT(DT), LI(LI),
    CouldNotCompute(new SCEVCouldNotCompute()), ValuesAtScopes(64),
    LoopDispositions(64), BlockDispositions(64) {
// To use guards for proving predicates, we need to scan every instruction in
// relevant basic blocks, and not just terminators.  Doing this is a waste of
// time if the IR does not actually contain any calls to
// @llvm.experimental.guard, so do a quick check and remember this beforehand.
//
// This pessimizes the case where a pass that preserves ScalarEvolution wants
// to _add_ guards to the module when there weren't any before, and wants
// ScalarEvolution to optimize based on those guards.  For now we prefer to be
// efficient in lieu of being smart in that rather obscure case.

auto *GuardDecl = F.getParent()->getFunction(
    Intrinsic::getName(Intrinsic::experimental_guard));
HasGuards = GuardDecl && !GuardDecl->use_empty();
12000}

12002ScalarEvolution::ScalarEvolution(ScalarEvolution &&Arg)
  : F(Arg.F), HasGuards(Arg.HasGuards), TLI(Arg.TLI), AC(Arg.AC), DT(Arg.DT),
    LI(Arg.LI), CouldNotCompute(std::move(Arg.CouldNotCompute)),
    ValueExprMap(std::move(Arg.ValueExprMap)),
    PendingLoopPredicates(std::move(Arg.PendingLoopPredicates)),
    PendingPhiRanges(std::move(Arg.PendingPhiRanges)),
    PendingMerges(std::move(Arg.PendingMerges)),
    MinTrailingZerosCache(std::move(Arg.MinTrailingZerosCache)),
    BackedgeTakenCounts(std::move(Arg.BackedgeTakenCounts)),
    PredicatedBackedgeTakenCounts(
        std::move(Arg.PredicatedBackedgeTakenCounts)),
    ConstantEvolutionLoopExitValue(
        std::move(Arg.ConstantEvolutionLoopExitValue)),
    ValuesAtScopes(std::move(Arg.ValuesAtScopes)),
    LoopDispositions(std::move(Arg.LoopDispositions)),
    LoopPropertiesCache(std::move(Arg.LoopPropertiesCache)),
    BlockDispositions(std::move(Arg.BlockDispositions)),
    UnsignedRanges(std::move(Arg.UnsignedRanges)),
    SignedRanges(std::move(Arg.SignedRanges)),
    UniqueSCEVs(std::move(Arg.UniqueSCEVs)),
    UniquePreds(std::move(Arg.UniquePreds)),
    SCEVAllocator(std::move(Arg.SCEVAllocator)),
    LoopUsers(std::move(Arg.LoopUsers)),
    PredicatedSCEVRewrites(std::move(Arg.PredicatedSCEVRewrites)),
    FirstUnknown(Arg.FirstUnknown) {
Arg.FirstUnknown = nullptr;
12028}

12030ScalarEvolution::~ScalarEvolution() {
// Iterate through all the SCEVUnknown instances and call their
// destructors, so that they release their references to their values.
for (SCEVUnknown *U = FirstUnknown; U;) {
  SCEVUnknown *Tmp = U;
  U = U->Next;
  Tmp->~SCEVUnknown();
}
FirstUnknown = nullptr;

ExprValueMap.clear();
ValueExprMap.clear();
HasRecMap.clear();

// Free any extra memory created for ExitNotTakenInfo in the unlikely event
// that a loop had multiple computable exits.
for (auto &BTCI : BackedgeTakenCounts)
  BTCI.second.clear();
for (auto &BTCI : PredicatedBackedgeTakenCounts)
  BTCI.second.clear();

assert(PendingLoopPredicates.empty() && "isImpliedCond garbage")((PendingLoopPredicates.empty() && "isImpliedCond garbage"
) ? static_cast<void> (0) : __assert_fail ("PendingLoopPredicates.empty() && \"isImpliedCond garbage\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12051, __PRETTY_FUNCTION__));
assert(PendingPhiRanges.empty() && "getRangeRef garbage")((PendingPhiRanges.empty() && "getRangeRef garbage") ?
 static_cast<void> (0) : __assert_fail ("PendingPhiRanges.empty() && \"getRangeRef garbage\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12052, __PRETTY_FUNCTION__));
assert(PendingMerges.empty() && "isImpliedViaMerge garbage")((PendingMerges.empty() && "isImpliedViaMerge garbage"
) ? static_cast<void> (0) : __assert_fail ("PendingMerges.empty() && \"isImpliedViaMerge garbage\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12053, __PRETTY_FUNCTION__));
assert(!WalkingBEDominatingConds && "isLoopBackedgeGuardedByCond garbage!")((!WalkingBEDominatingConds && "isLoopBackedgeGuardedByCond garbage!"
) ? static_cast<void> (0) : __assert_fail ("!WalkingBEDominatingConds && \"isLoopBackedgeGuardedByCond garbage!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12054, __PRETTY_FUNCTION__));
assert(!ProvingSplitPredicate && "ProvingSplitPredicate garbage!")((!ProvingSplitPredicate && "ProvingSplitPredicate garbage!"
) ? static_cast<void> (0) : __assert_fail ("!ProvingSplitPredicate && \"ProvingSplitPredicate garbage!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12055, __PRETTY_FUNCTION__));
12056}

12058bool ScalarEvolution::hasLoopInvariantBackedgeTakenCount(const Loop *L) {
return !isa<SCEVCouldNotCompute>(getBackedgeTakenCount(L));
12060}

12062static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE,
                        const Loop *L) {
// Print all inner loops first
for (Loop *I : *L)
  PrintLoopInfo(OS, SE, I);

OS << "Loop ";
L->getHeader()->printAsOperand(OS, /*PrintType=*/false);
OS << ": ";

SmallVector<BasicBlock *, 8> ExitingBlocks;
L->getExitingBlocks(ExitingBlocks);
if (ExitingBlocks.size() != 1)
  OS << "<multiple exits> ";

if (SE->hasLoopInvariantBackedgeTakenCount(L))
  OS << "backedge-taken count is " << *SE->getBackedgeTakenCount(L) << "\n";
else
  OS << "Unpredictable backedge-taken count.\n";

if (ExitingBlocks.size() > 1)
  for (BasicBlock *ExitingBlock : ExitingBlocks) {
    OS << "  exit count for " << ExitingBlock->getName() << ": "
       << *SE->getExitCount(L, ExitingBlock) << "\n";
  }

OS << "Loop ";
L->getHeader()->printAsOperand(OS, /*PrintType=*/false);
OS << ": ";

if (!isa<SCEVCouldNotCompute>(SE->getConstantMaxBackedgeTakenCount(L))) {
  OS << "max backedge-taken count is " << *SE->getConstantMaxBackedgeTakenCount(L);
  if (SE->isBackedgeTakenCountMaxOrZero(L))
    OS << ", actual taken count either this or zero.";
} else {
  OS << "Unpredictable max backedge-taken count. ";
}

OS << "\n"
      "Loop ";
L->getHeader()->printAsOperand(OS, /*PrintType=*/false);
OS << ": ";

SCEVUnionPredicate Pred;
auto PBT = SE->getPredicatedBackedgeTakenCount(L, Pred);
if (!isa<SCEVCouldNotCompute>(PBT)) {
  OS << "Predicated backedge-taken count is " << *PBT << "\n";
  OS << " Predicates:\n";
  Pred.print(OS, 4);
} else {
  OS << "Unpredictable predicated backedge-taken count. ";
}
OS << "\n";

if (SE->hasLoopInvariantBackedgeTakenCount(L)) {
  OS << "Loop ";
  L->getHeader()->printAsOperand(OS, /*PrintType=*/false);
  OS << ": ";
  OS << "Trip multiple is " << SE->getSmallConstantTripMultiple(L) << "\n";
}
12122}

12124static StringRef loopDispositionToStr(ScalarEvolution::LoopDisposition LD) {
switch (LD) {
case ScalarEvolution::LoopVariant:
  return "Variant";
case ScalarEvolution::LoopInvariant:
  return "Invariant";
case ScalarEvolution::LoopComputable:
  return "Computable";
}
llvm_unreachable("Unknown ScalarEvolution::LoopDisposition kind!")::llvm::llvm_unreachable_internal("Unknown ScalarEvolution::LoopDisposition kind!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12133);
12134}

12136void ScalarEvolution::print(raw_ostream &OS) const {
// ScalarEvolution's implementation of the print method is to print
// out SCEV values of all instructions that are interesting. Doing
// this potentially causes it to create new SCEV objects though,
// which technically conflicts with the const qualifier. This isn't
// observable from outside the class though, so casting away the
// const isn't dangerous.
ScalarEvolution &SE = *const_cast<ScalarEvolution *>(this);

if (ClassifyExpressions) {
  OS << "Classifying expressions for: ";
  F.printAsOperand(OS, /*PrintType=*/false);
  OS << "\n";
  for (Instruction &I : instructions(F))
    if (isSCEVable(I.getType()) && !isa<CmpInst>(I)) {
      OS << I << '\n';
      OS << "  -->  ";
      const SCEV *SV = SE.getSCEV(&I);
      SV->print(OS);
      if (!isa<SCEVCouldNotCompute>(SV)) {
        OS << " U: ";
        SE.getUnsignedRange(SV).print(OS);
        OS << " S: ";
        SE.getSignedRange(SV).print(OS);
      }

      const Loop *L = LI.getLoopFor(I.getParent());

      const SCEV *AtUse = SE.getSCEVAtScope(SV, L);
      if (AtUse != SV) {
        OS << "  -->  ";
        AtUse->print(OS);
        if (!isa<SCEVCouldNotCompute>(AtUse)) {
          OS << " U: ";
          SE.getUnsignedRange(AtUse).print(OS);
          OS << " S: ";
          SE.getSignedRange(AtUse).print(OS);
        }
      }

      if (L) {
        OS << "\t\t" "Exits: ";
        const SCEV *ExitValue = SE.getSCEVAtScope(SV, L->getParentLoop());
        if (!SE.isLoopInvariant(ExitValue, L)) {
          OS << "<<Unknown>>";
        } else {
          OS << *ExitValue;
        }

        bool First = true;
        for (auto *Iter = L; Iter; Iter = Iter->getParentLoop()) {
          if (First) {
            OS << "\t\t" "LoopDispositions: { ";
            First = false;
          } else {
            OS << ", ";
          }

          Iter->getHeader()->printAsOperand(OS, /*PrintType=*/false);
          OS << ": " << loopDispositionToStr(SE.getLoopDisposition(SV, Iter));
        }

        for (auto *InnerL : depth_first(L)) {
          if (InnerL == L)
            continue;
          if (First) {
            OS << "\t\t" "LoopDispositions: { ";
            First = false;
          } else {
            OS << ", ";
          }

          InnerL->getHeader()->printAsOperand(OS, /*PrintType=*/false);
          OS << ": " << loopDispositionToStr(SE.getLoopDisposition(SV, InnerL));
        }

        OS << " }";
      }

      OS << "\n";
    }
}

OS << "Determining loop execution counts for: ";
F.printAsOperand(OS, /*PrintType=*/false);
OS << "\n";
for (Loop *I : LI)
  PrintLoopInfo(OS, &SE, I);
12224}

12226ScalarEvolution::LoopDisposition
12227ScalarEvolution::getLoopDisposition(const SCEV *S, const Loop *L) {
auto &Values = LoopDispositions[S];
for (auto &V : Values) {
  if (V.getPointer() == L)
    return V.getInt();
}
Values.emplace_back(L, LoopVariant);
LoopDisposition D = computeLoopDisposition(S, L);
auto &Values2 = LoopDispositions[S];
for (auto &V : make_range(Values2.rbegin(), Values2.rend())) {
  if (V.getPointer() == L) {
    V.setInt(D);
    break;
  }
}
return D;
12243}

12245ScalarEvolution::LoopDisposition
12246ScalarEvolution::computeLoopDisposition(const SCEV *S, const Loop *L) {
switch (S->getSCEVType()) {
case scConstant:
  return LoopInvariant;
case scPtrToInt:
case scTruncate:
case scZeroExtend:
case scSignExtend:
  return getLoopDisposition(cast<SCEVCastExpr>(S)->getOperand(), L);
case scAddRecExpr: {
  const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(S);

  // If L is the addrec's loop, it's computable.
  if (AR->getLoop() == L)
    return LoopComputable;

  // Add recurrences are never invariant in the function-body (null loop).
  if (!L)
    return LoopVariant;

  // Everything that is not defined at loop entry is variant.
  if (DT.dominates(L->getHeader(), AR->getLoop()->getHeader()))
    return LoopVariant;
  assert(!L->contains(AR->getLoop()) && "Containing loop's header does not"((!L->contains(AR->getLoop()) && "Containing loop's header does not"
 " dominate the contained loop's header?") ? static_cast<void
> (0) : __assert_fail ("!L->contains(AR->getLoop()) && \"Containing loop's header does not\" \" dominate the contained loop's header?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12270, __PRETTY_FUNCTION__))
         " dominate the contained loop's header?")((!L->contains(AR->getLoop()) && "Containing loop's header does not"
 " dominate the contained loop's header?") ? static_cast<void
> (0) : __assert_fail ("!L->contains(AR->getLoop()) && \"Containing loop's header does not\" \" dominate the contained loop's header?\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12270, __PRETTY_FUNCTION__));

  // This recurrence is invariant w.r.t. L if AR's loop contains L.
  if (AR->getLoop()->contains(L))
    return LoopInvariant;

  // This recurrence is variant w.r.t. L if any of its operands
  // are variant.
  for (auto *Op : AR->operands())
    if (!isLoopInvariant(Op, L))
      return LoopVariant;

  // Otherwise it's loop-invariant.
  return LoopInvariant;
}
case scAddExpr:
case scMulExpr:
case scUMaxExpr:
case scSMaxExpr:
case scUMinExpr:
case scSMinExpr: {
  bool HasVarying = false;
  for (auto *Op : cast<SCEVNAryExpr>(S)->operands()) {
    LoopDisposition D = getLoopDisposition(Op, L);
    if (D == LoopVariant)
      return LoopVariant;
    if (D == LoopComputable)
      HasVarying = true;
  }
  return HasVarying ? LoopComputable : LoopInvariant;
}
case scUDivExpr: {
  const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S);
  LoopDisposition LD = getLoopDisposition(UDiv->getLHS(), L);
  if (LD == LoopVariant)
    return LoopVariant;
  LoopDisposition RD = getLoopDisposition(UDiv->getRHS(), L);
  if (RD == LoopVariant)
    return LoopVariant;
  return (LD == LoopInvariant && RD == LoopInvariant) ?
         LoopInvariant : LoopComputable;
}
case scUnknown:
  // All non-instruction values are loop invariant.  All instructions are loop
  // invariant if they are not contained in the specified loop.
  // Instructions are never considered invariant in the function body
  // (null loop) because they are defined within the "loop".
  if (auto *I = dyn_cast<Instruction>(cast<SCEVUnknown>(S)->getValue()))
    return (L && !L->contains(I)) ? LoopInvariant : LoopVariant;
  return LoopInvariant;
case scCouldNotCompute:
  llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12321);
}
llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12323);
12324}

12326bool ScalarEvolution::isLoopInvariant(const SCEV *S, const Loop *L) {
return getLoopDisposition(S, L) == LoopInvariant;
2
←
Assuming the condition is false→
3
←
Returning zero, which participates in a condition later→
7
←
Assuming the condition is true→
8
←
Returning the value 1, which participates in a condition later→
12328}

12330bool ScalarEvolution::hasComputableLoopEvolution(const SCEV *S, const Loop *L) {
return getLoopDisposition(S, L) == LoopComputable;
12332}

12334ScalarEvolution::BlockDisposition
12335ScalarEvolution::getBlockDisposition(const SCEV *S, const BasicBlock *BB) {
auto &Values = BlockDispositions[S];
for (auto &V : Values) {
  if (V.getPointer() == BB)
    return V.getInt();
}
Values.emplace_back(BB, DoesNotDominateBlock);
BlockDisposition D = computeBlockDisposition(S, BB);
auto &Values2 = BlockDispositions[S];
for (auto &V : make_range(Values2.rbegin(), Values2.rend())) {
  if (V.getPointer() == BB) {
    V.setInt(D);
    break;
  }
}
return D;
12351}

12353ScalarEvolution::BlockDisposition
12354ScalarEvolution::computeBlockDisposition(const SCEV *S, const BasicBlock *BB) {
switch (S->getSCEVType()) {
case scConstant:
  return ProperlyDominatesBlock;
case scPtrToInt:
case scTruncate:
case scZeroExtend:
case scSignExtend:
  return getBlockDisposition(cast<SCEVCastExpr>(S)->getOperand(), BB);
case scAddRecExpr: {
  // This uses a "dominates" query instead of "properly dominates" query
  // to test for proper dominance too, because the instruction which
  // produces the addrec's value is a PHI, and a PHI effectively properly
  // dominates its entire containing block.
  const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(S);
  if (!DT.dominates(AR->getLoop()->getHeader(), BB))
    return DoesNotDominateBlock;

  // Fall through into SCEVNAryExpr handling.
  LLVM_FALLTHROUGH[[gnu::fallthrough]];
}
case scAddExpr:
case scMulExpr:
case scUMaxExpr:
case scSMaxExpr:
case scUMinExpr:
case scSMinExpr: {
  const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(S);
  bool Proper = true;
  for (const SCEV *NAryOp : NAry->operands()) {
    BlockDisposition D = getBlockDisposition(NAryOp, BB);
    if (D == DoesNotDominateBlock)
      return DoesNotDominateBlock;
    if (D == DominatesBlock)
      Proper = false;
  }
  return Proper ? ProperlyDominatesBlock : DominatesBlock;
}
case scUDivExpr: {
  const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S);
  const SCEV *LHS = UDiv->getLHS(), *RHS = UDiv->getRHS();
  BlockDisposition LD = getBlockDisposition(LHS, BB);
  if (LD == DoesNotDominateBlock)
    return DoesNotDominateBlock;
  BlockDisposition RD = getBlockDisposition(RHS, BB);
  if (RD == DoesNotDominateBlock)
    return DoesNotDominateBlock;
  return (LD == ProperlyDominatesBlock && RD == ProperlyDominatesBlock) ?
    ProperlyDominatesBlock : DominatesBlock;
}
case scUnknown:
  if (Instruction *I =
        dyn_cast<Instruction>(cast<SCEVUnknown>(S)->getValue())) {
    if (I->getParent() == BB)
      return DominatesBlock;
    if (DT.properlyDominates(I->getParent(), BB))
      return ProperlyDominatesBlock;
    return DoesNotDominateBlock;
  }
  return ProperlyDominatesBlock;
case scCouldNotCompute:
  llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12415);
}
llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12417);
12418}

12420bool ScalarEvolution::dominates(const SCEV *S, const BasicBlock *BB) {
return getBlockDisposition(S, BB) >= DominatesBlock;
12422}

12424bool ScalarEvolution::properlyDominates(const SCEV *S, const BasicBlock *BB) {
return getBlockDisposition(S, BB) == ProperlyDominatesBlock;
12426}

12428bool ScalarEvolution::hasOperand(const SCEV *S, const SCEV *Op) const {
return SCEVExprContains(S, [&](const SCEV *Expr) { return Expr == Op; });
12430}

12432bool ScalarEvolution::ExitLimit::hasOperand(const SCEV *S) const {
auto IsS = [&](const SCEV *X) { return S == X; };
auto ContainsS = [&](const SCEV *X) {
  return !isa<SCEVCouldNotCompute>(X) && SCEVExprContains(X, IsS);
};
return ContainsS(ExactNotTaken) || ContainsS(MaxNotTaken);
12438}

12440void
12441ScalarEvolution::forgetMemoizedResults(const SCEV *S) {
ValuesAtScopes.erase(S);
LoopDispositions.erase(S);
BlockDispositions.erase(S);
UnsignedRanges.erase(S);
SignedRanges.erase(S);
ExprValueMap.erase(S);
HasRecMap.erase(S);
MinTrailingZerosCache.erase(S);

for (auto I = PredicatedSCEVRewrites.begin();
     I != PredicatedSCEVRewrites.end();) {
  std::pair<const SCEV *, const Loop *> Entry = I->first;
  if (Entry.first == S)
    PredicatedSCEVRewrites.erase(I++);
  else
    ++I;
}

auto RemoveSCEVFromBackedgeMap =
    [S, this](DenseMap<const Loop *, BackedgeTakenInfo> &Map) {
      for (auto I = Map.begin(), E = Map.end(); I != E;) {
        BackedgeTakenInfo &BEInfo = I->second;
        if (BEInfo.hasOperand(S, this)) {
          BEInfo.clear();
          Map.erase(I++);
        } else
          ++I;
      }
    };

RemoveSCEVFromBackedgeMap(BackedgeTakenCounts);
RemoveSCEVFromBackedgeMap(PredicatedBackedgeTakenCounts);
12474}

12476void
12477ScalarEvolution::getUsedLoops(const SCEV *S,
                            SmallPtrSetImpl<const Loop *> &LoopsUsed) {
struct FindUsedLoops {
  FindUsedLoops(SmallPtrSetImpl<const Loop *> &LoopsUsed)
      : LoopsUsed(LoopsUsed) {}
  SmallPtrSetImpl<const Loop *> &LoopsUsed;
  bool follow(const SCEV *S) {
    if (auto *AR = dyn_cast<SCEVAddRecExpr>(S))
      LoopsUsed.insert(AR->getLoop());
    return true;
  }

  bool isDone() const { return false; }
};

FindUsedLoops F(LoopsUsed);
SCEVTraversal<FindUsedLoops>(F).visitAll(S);
12494}

12496void ScalarEvolution::addToLoopUseLists(const SCEV *S) {
SmallPtrSet<const Loop *, 8> LoopsUsed;
getUsedLoops(S, LoopsUsed);
for (auto *L : LoopsUsed)
  LoopUsers[L].push_back(S);
12501}

12503void ScalarEvolution::verify() const {
ScalarEvolution &SE = *const_cast<ScalarEvolution *>(this);
ScalarEvolution SE2(F, TLI, AC, DT, LI);

SmallVector<Loop *, 8> LoopStack(LI.begin(), LI.end());

// Map's SCEV expressions from one ScalarEvolution "universe" to another.
struct SCEVMapper : public SCEVRewriteVisitor<SCEVMapper> {
  SCEVMapper(ScalarEvolution &SE) : SCEVRewriteVisitor<SCEVMapper>(SE) {}

  const SCEV *visitConstant(const SCEVConstant *Constant) {
    return SE.getConstant(Constant->getAPInt());
  }

  const SCEV *visitUnknown(const SCEVUnknown *Expr) {
    return SE.getUnknown(Expr->getValue());
  }

  const SCEV *visitCouldNotCompute(const SCEVCouldNotCompute *Expr) {
    return SE.getCouldNotCompute();
  }
};

SCEVMapper SCM(SE2);

while (!LoopStack.empty()) {
  auto *L = LoopStack.pop_back_val();
  LoopStack.insert(LoopStack.end(), L->begin(), L->end());

  auto *CurBECount = SCM.visit(
      const_cast<ScalarEvolution *>(this)->getBackedgeTakenCount(L));
  auto *NewBECount = SE2.getBackedgeTakenCount(L);

  if (CurBECount == SE2.getCouldNotCompute() ||
      NewBECount == SE2.getCouldNotCompute()) {
    // NB! This situation is legal, but is very suspicious -- whatever pass
    // change the loop to make a trip count go from could not compute to
    // computable or vice-versa *should have* invalidated SCEV.  However, we
    // choose not to assert here (for now) since we don't want false
    // positives.
    continue;
  }

  if (containsUndefs(CurBECount) || containsUndefs(NewBECount)) {
    // SCEV treats "undef" as an unknown but consistent value (i.e. it does
    // not propagate undef aggressively).  This means we can (and do) fail
    // verification in cases where a transform makes the trip count of a loop
    // go from "undef" to "undef+1" (say).  The transform is fine, since in
    // both cases the loop iterates "undef" times, but SCEV thinks we
    // increased the trip count of the loop by 1 incorrectly.
    continue;
  }

  if (SE.getTypeSizeInBits(CurBECount->getType()) >
      SE.getTypeSizeInBits(NewBECount->getType()))
    NewBECount = SE2.getZeroExtendExpr(NewBECount, CurBECount->getType());
  else if (SE.getTypeSizeInBits(CurBECount->getType()) <
           SE.getTypeSizeInBits(NewBECount->getType()))
    CurBECount = SE2.getZeroExtendExpr(CurBECount, NewBECount->getType());

  const SCEV *Delta = SE2.getMinusSCEV(CurBECount, NewBECount);

  // Unless VerifySCEVStrict is set, we only compare constant deltas.
  if ((VerifySCEVStrict || isa<SCEVConstant>(Delta)) && !Delta->isZero()) {
    dbgs() << "Trip Count for " << *L << " Changed!\n";
    dbgs() << "Old: " << *CurBECount << "\n";
    dbgs() << "New: " << *NewBECount << "\n";
    dbgs() << "Delta: " << *Delta << "\n";
    std::abort();
  }
}

// Collect all valid loops currently in LoopInfo.
SmallPtrSet<Loop *, 32> ValidLoops;
SmallVector<Loop *, 32> Worklist(LI.begin(), LI.end());
while (!Worklist.empty()) {
  Loop *L = Worklist.pop_back_val();
  if (ValidLoops.contains(L))
    continue;
  ValidLoops.insert(L);
  Worklist.append(L->begin(), L->end());
}
// Check for SCEV expressions referencing invalid/deleted loops.
for (auto &KV : ValueExprMap) {
  auto *AR = dyn_cast<SCEVAddRecExpr>(KV.second);
  if (!AR)
    continue;
  assert(ValidLoops.contains(AR->getLoop()) &&((ValidLoops.contains(AR->getLoop()) && "AddRec references invalid loop"
) ? static_cast<void> (0) : __assert_fail ("ValidLoops.contains(AR->getLoop()) && \"AddRec references invalid loop\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12591, __PRETTY_FUNCTION__))
         "AddRec references invalid loop")((ValidLoops.contains(AR->getLoop()) && "AddRec references invalid loop"
) ? static_cast<void> (0) : __assert_fail ("ValidLoops.contains(AR->getLoop()) && \"AddRec references invalid loop\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12591, __PRETTY_FUNCTION__));
}
12593}

12595bool ScalarEvolution::invalidate(
  Function &F, const PreservedAnalyses &PA,
  FunctionAnalysisManager::Invalidator &Inv) {
// Invalidate the ScalarEvolution object whenever it isn't preserved or one
// of its dependencies is invalidated.
auto PAC = PA.getChecker<ScalarEvolutionAnalysis>();
return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>()) ||
       Inv.invalidate<AssumptionAnalysis>(F, PA) ||
       Inv.invalidate<DominatorTreeAnalysis>(F, PA) ||
       Inv.invalidate<LoopAnalysis>(F, PA);
12605}

12607AnalysisKey ScalarEvolutionAnalysis::Key;

12609ScalarEvolution ScalarEvolutionAnalysis::run(Function &F,
                                           FunctionAnalysisManager &AM) {
return ScalarEvolution(F, AM.getResult<TargetLibraryAnalysis>(F),
                       AM.getResult<AssumptionAnalysis>(F),
                       AM.getResult<DominatorTreeAnalysis>(F),
                       AM.getResult<LoopAnalysis>(F));
12615}

12617PreservedAnalyses
12618ScalarEvolutionVerifierPass::run(Function &F, FunctionAnalysisManager &AM) {
AM.getResult<ScalarEvolutionAnalysis>(F).verify();
return PreservedAnalyses::all();
12621}

12623PreservedAnalyses
12624ScalarEvolutionPrinterPass::run(Function &F, FunctionAnalysisManager &AM) {
// For compatibility with opt's -analyze feature under legacy pass manager
// which was not ported to NPM. This keeps tests using
// update_analyze_test_checks.py working.
OS << "Printing analysis 'Scalar Evolution Analysis' for function '"
   << F.getName() << "':\n";
AM.getResult<ScalarEvolutionAnalysis>(F).print(OS);
return PreservedAnalyses::all();
12632}

12634INITIALIZE_PASS_BEGIN(ScalarEvolutionWrapperPass, "scalar-evolution",static void *initializeScalarEvolutionWrapperPassPassOnce(PassRegistry
 &Registry) {
                    "Scalar Evolution Analysis", false, true)static void *initializeScalarEvolutionWrapperPassPassOnce(PassRegistry
 &Registry) {
12636INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry);
12637INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)initializeLoopInfoWrapperPassPass(Registry);
12638INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
12639INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
12640INITIALIZE_PASS_END(ScalarEvolutionWrapperPass, "scalar-evolution",PassInfo *PI = new PassInfo( "Scalar Evolution Analysis", "scalar-evolution"
, &ScalarEvolutionWrapperPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<ScalarEvolutionWrapperPass>), false, true
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeScalarEvolutionWrapperPassPassFlag; void
 llvm::initializeScalarEvolutionWrapperPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeScalarEvolutionWrapperPassPassFlag
, initializeScalarEvolutionWrapperPassPassOnce, std::ref(Registry
)); }
                  "Scalar Evolution Analysis", false, true)PassInfo *PI = new PassInfo( "Scalar Evolution Analysis", "scalar-evolution"
, &ScalarEvolutionWrapperPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<ScalarEvolutionWrapperPass>), false, true
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeScalarEvolutionWrapperPassPassFlag; void
 llvm::initializeScalarEvolutionWrapperPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeScalarEvolutionWrapperPassPassFlag
, initializeScalarEvolutionWrapperPassPassOnce, std::ref(Registry
)); }

12643char ScalarEvolutionWrapperPass::ID = 0;

12645ScalarEvolutionWrapperPass::ScalarEvolutionWrapperPass() : FunctionPass(ID) {
initializeScalarEvolutionWrapperPassPass(*PassRegistry::getPassRegistry());
12647}

12649bool ScalarEvolutionWrapperPass::runOnFunction(Function &F) {
SE.reset(new ScalarEvolution(
    F, getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F),
    getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F),
    getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
    getAnalysis<LoopInfoWrapperPass>().getLoopInfo()));
return false;
12656}

12658void ScalarEvolutionWrapperPass::releaseMemory() { SE.reset(); }

12660void ScalarEvolutionWrapperPass::print(raw_ostream &OS, const Module *) const {
SE->print(OS);
12662}

12664void ScalarEvolutionWrapperPass::verifyAnalysis() const {
if (!VerifySCEV)
  return;

SE->verify();
12669}

12671void ScalarEvolutionWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequiredTransitive<AssumptionCacheTracker>();
AU.addRequiredTransitive<LoopInfoWrapperPass>();
AU.addRequiredTransitive<DominatorTreeWrapperPass>();
AU.addRequiredTransitive<TargetLibraryInfoWrapperPass>();
12677}

12679const SCEVPredicate *ScalarEvolution::getEqualPredicate(const SCEV *LHS,
                                                      const SCEV *RHS) {
FoldingSetNodeID ID;
assert(LHS->getType() == RHS->getType() &&((LHS->getType() == RHS->getType() && "Type mismatch between LHS and RHS"
) ? static_cast<void> (0) : __assert_fail ("LHS->getType() == RHS->getType() && \"Type mismatch between LHS and RHS\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12683, __PRETTY_FUNCTION__))
       "Type mismatch between LHS and RHS")((LHS->getType() == RHS->getType() && "Type mismatch between LHS and RHS"
) ? static_cast<void> (0) : __assert_fail ("LHS->getType() == RHS->getType() && \"Type mismatch between LHS and RHS\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12683, __PRETTY_FUNCTION__));
// Unique this node based on the arguments
ID.AddInteger(SCEVPredicate::P_Equal);
ID.AddPointer(LHS);
ID.AddPointer(RHS);
void *IP = nullptr;
if (const auto *S = UniquePreds.FindNodeOrInsertPos(ID, IP))
  return S;
SCEVEqualPredicate *Eq = new (SCEVAllocator)
    SCEVEqualPredicate(ID.Intern(SCEVAllocator), LHS, RHS);
UniquePreds.InsertNode(Eq, IP);
return Eq;
12695}

12697const SCEVPredicate *ScalarEvolution::getWrapPredicate(
  const SCEVAddRecExpr *AR,
  SCEVWrapPredicate::IncrementWrapFlags AddedFlags) {
FoldingSetNodeID ID;
// Unique this node based on the arguments
ID.AddInteger(SCEVPredicate::P_Wrap);
ID.AddPointer(AR);
ID.AddInteger(AddedFlags);
void *IP = nullptr;
if (const auto *S = UniquePreds.FindNodeOrInsertPos(ID, IP))
  return S;
auto *OF = new (SCEVAllocator)
    SCEVWrapPredicate(ID.Intern(SCEVAllocator), AR, AddedFlags);
UniquePreds.InsertNode(OF, IP);
return OF;
12712}

12714namespace {

12716class SCEVPredicateRewriter : public SCEVRewriteVisitor<SCEVPredicateRewriter> {
12717public:

/// Rewrites \p S in the context of a loop L and the SCEV predication
/// infrastructure.
///
/// If \p Pred is non-null, the SCEV expression is rewritten to respect the
/// equivalences present in \p Pred.
///
/// If \p NewPreds is non-null, rewrite is free to add further predicates to
/// \p NewPreds such that the result will be an AddRecExpr.
static const SCEV *rewrite(const SCEV *S, const Loop *L, ScalarEvolution &SE,
                           SmallPtrSetImpl<const SCEVPredicate *> *NewPreds,
                           SCEVUnionPredicate *Pred) {
  SCEVPredicateRewriter Rewriter(L, SE, NewPreds, Pred);
  return Rewriter.visit(S);
}

const SCEV *visitUnknown(const SCEVUnknown *Expr) {
  if (Pred) {
    auto ExprPreds = Pred->getPredicatesForExpr(Expr);
    for (auto *Pred : ExprPreds)
      if (const auto *IPred = dyn_cast<SCEVEqualPredicate>(Pred))
        if (IPred->getLHS() == Expr)
          return IPred->getRHS();
  }
  return convertToAddRecWithPreds(Expr);
}

const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *Expr) {
  const SCEV *Operand = visit(Expr->getOperand());
  const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Operand);
  if (AR && AR->getLoop() == L && AR->isAffine()) {
    // This couldn't be folded because the operand didn't have the nuw
    // flag. Add the nusw flag as an assumption that we could make.
    const SCEV *Step = AR->getStepRecurrence(SE);
    Type *Ty = Expr->getType();
    if (addOverflowAssumption(AR, SCEVWrapPredicate::IncrementNUSW))
      return SE.getAddRecExpr(SE.getZeroExtendExpr(AR->getStart(), Ty),
                              SE.getSignExtendExpr(Step, Ty), L,
                              AR->getNoWrapFlags());
  }
  return SE.getZeroExtendExpr(Operand, Expr->getType());
}

const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) {
  const SCEV *Operand = visit(Expr->getOperand());
  const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Operand);
  if (AR && AR->getLoop() == L && AR->isAffine()) {
    // This couldn't be folded because the operand didn't have the nsw
    // flag. Add the nssw flag as an assumption that we could make.
    const SCEV *Step = AR->getStepRecurrence(SE);
    Type *Ty = Expr->getType();
    if (addOverflowAssumption(AR, SCEVWrapPredicate::IncrementNSSW))
      return SE.getAddRecExpr(SE.getSignExtendExpr(AR->getStart(), Ty),
                              SE.getSignExtendExpr(Step, Ty), L,
                              AR->getNoWrapFlags());
  }
  return SE.getSignExtendExpr(Operand, Expr->getType());
}

12777private:
explicit SCEVPredicateRewriter(const Loop *L, ScalarEvolution &SE,
                      SmallPtrSetImpl<const SCEVPredicate *> *NewPreds,
                      SCEVUnionPredicate *Pred)
    : SCEVRewriteVisitor(SE), NewPreds(NewPreds), Pred(Pred), L(L) {}

bool addOverflowAssumption(const SCEVPredicate *P) {
  if (!NewPreds) {
    // Check if we've already made this assumption.
    return Pred && Pred->implies(P);
  }
  NewPreds->insert(P);
  return true;
}

bool addOverflowAssumption(const SCEVAddRecExpr *AR,
                           SCEVWrapPredicate::IncrementWrapFlags AddedFlags) {
  auto *A = SE.getWrapPredicate(AR, AddedFlags);
  return addOverflowAssumption(A);
}

// If \p Expr represents a PHINode, we try to see if it can be represented
// as an AddRec, possibly under a predicate (PHISCEVPred). If it is possible
// to add this predicate as a runtime overflow check, we return the AddRec.
// If \p Expr does not meet these conditions (is not a PHI node, or we
// couldn't create an AddRec for it, or couldn't add the predicate), we just
// return \p Expr.
const SCEV *convertToAddRecWithPreds(const SCEVUnknown *Expr) {
  if (!isa<PHINode>(Expr->getValue()))
    return Expr;
  Optional<std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>>
  PredicatedRewrite = SE.createAddRecFromPHIWithCasts(Expr);
  if (!PredicatedRewrite)
    return Expr;
  for (auto *P : PredicatedRewrite->second){
    // Wrap predicates from outer loops are not supported.
    if (auto *WP = dyn_cast<const SCEVWrapPredicate>(P)) {
      auto *AR = cast<const SCEVAddRecExpr>(WP->getExpr());
      if (L != AR->getLoop())
        return Expr;
    }
    if (!addOverflowAssumption(P))
      return Expr;
  }
  return PredicatedRewrite->first;
}

SmallPtrSetImpl<const SCEVPredicate *> *NewPreds;
SCEVUnionPredicate *Pred;
const Loop *L;
12827};

12829} // end anonymous namespace

12831const SCEV *ScalarEvolution::rewriteUsingPredicate(const SCEV *S, const Loop *L,
                                                 SCEVUnionPredicate &Preds) {
return SCEVPredicateRewriter::rewrite(S, L, *this, nullptr, &Preds);
12834}

12836const SCEVAddRecExpr *ScalarEvolution::convertSCEVToAddRecWithPredicates(
  const SCEV *S, const Loop *L,
  SmallPtrSetImpl<const SCEVPredicate *> &Preds) {
SmallPtrSet<const SCEVPredicate *, 4> TransformPreds;
S = SCEVPredicateRewriter::rewrite(S, L, *this, &TransformPreds, nullptr);
auto *AddRec = dyn_cast<SCEVAddRecExpr>(S);

if (!AddRec)
  return nullptr;

// Since the transformation was successful, we can now transfer the SCEV
// predicates.
for (auto *P : TransformPreds)
  Preds.insert(P);

return AddRec;
12852}

12854/// SCEV predicates
12855SCEVPredicate::SCEVPredicate(const FoldingSetNodeIDRef ID,
                           SCEVPredicateKind Kind)
  : FastID(ID), Kind(Kind) {}

12859SCEVEqualPredicate::SCEVEqualPredicate(const FoldingSetNodeIDRef ID,
                                     const SCEV *LHS, const SCEV *RHS)
  : SCEVPredicate(ID, P_Equal), LHS(LHS), RHS(RHS) {
assert(LHS->getType() == RHS->getType() && "LHS and RHS types don't match")((LHS->getType() == RHS->getType() && "LHS and RHS types don't match"
) ? static_cast<void> (0) : __assert_fail ("LHS->getType() == RHS->getType() && \"LHS and RHS types don't match\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12862, __PRETTY_FUNCTION__));
assert(LHS != RHS && "LHS and RHS are the same SCEV")((LHS != RHS && "LHS and RHS are the same SCEV") ? static_cast
<void> (0) : __assert_fail ("LHS != RHS && \"LHS and RHS are the same SCEV\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12863, __PRETTY_FUNCTION__));
12864}

12866bool SCEVEqualPredicate::implies(const SCEVPredicate *N) const {
const auto *Op = dyn_cast<SCEVEqualPredicate>(N);

if (!Op)
  return false;

return Op->LHS == LHS && Op->RHS == RHS;
12873}

12875bool SCEVEqualPredicate::isAlwaysTrue() const { return false; }

12877const SCEV *SCEVEqualPredicate::getExpr() const { return LHS; }

12879void SCEVEqualPredicate::print(raw_ostream &OS, unsigned Depth) const {
OS.indent(Depth) << "Equal predicate: " << *LHS << " == " << *RHS << "\n";
12881}

12883SCEVWrapPredicate::SCEVWrapPredicate(const FoldingSetNodeIDRef ID,
                                   const SCEVAddRecExpr *AR,
                                   IncrementWrapFlags Flags)
  : SCEVPredicate(ID, P_Wrap), AR(AR), Flags(Flags) {}

12888const SCEV *SCEVWrapPredicate::getExpr() const { return AR; }

12890bool SCEVWrapPredicate::implies(const SCEVPredicate *N) const {
const auto *Op = dyn_cast<SCEVWrapPredicate>(N);

return Op && Op->AR == AR && setFlags(Flags, Op->Flags) == Flags;
12894}

12896bool SCEVWrapPredicate::isAlwaysTrue() const {
SCEV::NoWrapFlags ScevFlags = AR->getNoWrapFlags();
IncrementWrapFlags IFlags = Flags;

if (ScalarEvolution::setFlags(ScevFlags, SCEV::FlagNSW) == ScevFlags)
  IFlags = clearFlags(IFlags, IncrementNSSW);

return IFlags == IncrementAnyWrap;
12904}

12906void SCEVWrapPredicate::print(raw_ostream &OS, unsigned Depth) const {
OS.indent(Depth) << *getExpr() << " Added Flags: ";
if (SCEVWrapPredicate::IncrementNUSW & getFlags())
  OS << "<nusw>";
if (SCEVWrapPredicate::IncrementNSSW & getFlags())
  OS << "<nssw>";
OS << "\n";
12913}

12915SCEVWrapPredicate::IncrementWrapFlags
12916SCEVWrapPredicate::getImpliedFlags(const SCEVAddRecExpr *AR,
                                 ScalarEvolution &SE) {
IncrementWrapFlags ImpliedFlags = IncrementAnyWrap;
SCEV::NoWrapFlags StaticFlags = AR->getNoWrapFlags();

// We can safely transfer the NSW flag as NSSW.
if (ScalarEvolution::setFlags(StaticFlags, SCEV::FlagNSW) == StaticFlags)
  ImpliedFlags = IncrementNSSW;

if (ScalarEvolution::setFlags(StaticFlags, SCEV::FlagNUW) == StaticFlags) {
  // If the increment is positive, the SCEV NUW flag will also imply the
  // WrapPredicate NUSW flag.
  if (const auto *Step = dyn_cast<SCEVConstant>(AR->getStepRecurrence(SE)))
    if (Step->getValue()->getValue().isNonNegative())
      ImpliedFlags = setFlags(ImpliedFlags, IncrementNUSW);
}

return ImpliedFlags;
12934}

12936/// Union predicates don't get cached so create a dummy set ID for it.
12937SCEVUnionPredicate::SCEVUnionPredicate()
  : SCEVPredicate(FoldingSetNodeIDRef(nullptr, 0), P_Union) {}

12940bool SCEVUnionPredicate::isAlwaysTrue() const {
return all_of(Preds,
              [](const SCEVPredicate *I) { return I->isAlwaysTrue(); });
12943}

12945ArrayRef<const SCEVPredicate *>
12946SCEVUnionPredicate::getPredicatesForExpr(const SCEV *Expr) {
auto I = SCEVToPreds.find(Expr);
if (I == SCEVToPreds.end())
  return ArrayRef<const SCEVPredicate *>();
return I->second;
12951}

12953bool SCEVUnionPredicate::implies(const SCEVPredicate *N) const {
if (const auto *Set = dyn_cast<SCEVUnionPredicate>(N))
  return all_of(Set->Preds,
                [this](const SCEVPredicate *I) { return this->implies(I); });

auto ScevPredsIt = SCEVToPreds.find(N->getExpr());
if (ScevPredsIt == SCEVToPreds.end())
  return false;
auto &SCEVPreds = ScevPredsIt->second;

return any_of(SCEVPreds,
              [N](const SCEVPredicate *I) { return I->implies(N); });
12965}

12967const SCEV *SCEVUnionPredicate::getExpr() const { return nullptr; }

12969void SCEVUnionPredicate::print(raw_ostream &OS, unsigned Depth) const {
for (auto Pred : Preds)
  Pred->print(OS, Depth);
12972}

12974void SCEVUnionPredicate::add(const SCEVPredicate *N) {
if (const auto *Set = dyn_cast<SCEVUnionPredicate>(N)) {
  for (auto Pred : Set->Preds)
    add(Pred);
  return;
}

if (implies(N))
  return;

const SCEV *Key = N->getExpr();
assert(Key && "Only SCEVUnionPredicate doesn't have an "((Key && "Only SCEVUnionPredicate doesn't have an " " associated expression!"
) ? static_cast<void> (0) : __assert_fail ("Key && \"Only SCEVUnionPredicate doesn't have an \" \" associated expression!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12986, __PRETTY_FUNCTION__))
              " associated expression!")((Key && "Only SCEVUnionPredicate doesn't have an " " associated expression!"
) ? static_cast<void> (0) : __assert_fail ("Key && \"Only SCEVUnionPredicate doesn't have an \" \" associated expression!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 12986, __PRETTY_FUNCTION__));

SCEVToPreds[Key].push_back(N);
Preds.push_back(N);
12990}

12992PredicatedScalarEvolution::PredicatedScalarEvolution(ScalarEvolution &SE,
                                                   Loop &L)
  : SE(SE), L(L) {}

12996const SCEV *PredicatedScalarEvolution::getSCEV(Value *V) {
const SCEV *Expr = SE.getSCEV(V);
RewriteEntry &Entry = RewriteMap[Expr];

// If we already have an entry and the version matches, return it.
if (Entry.second && Generation == Entry.first)
  return Entry.second;

// We found an entry but it's stale. Rewrite the stale entry
// according to the current predicate.
if (Entry.second)
  Expr = Entry.second;

const SCEV *NewSCEV = SE.rewriteUsingPredicate(Expr, &L, Preds);
Entry = {Generation, NewSCEV};

return NewSCEV;
13013}

13015const SCEV *PredicatedScalarEvolution::getBackedgeTakenCount() {
if (!BackedgeCount) {
  SCEVUnionPredicate BackedgePred;
  BackedgeCount = SE.getPredicatedBackedgeTakenCount(&L, BackedgePred);
  addPredicate(BackedgePred);
}
return BackedgeCount;
13022}

13024void PredicatedScalarEvolution::addPredicate(const SCEVPredicate &Pred) {
if (Preds.implies(&Pred))
  return;
Preds.add(&Pred);
updateGeneration();
13029}

13031const SCEVUnionPredicate &PredicatedScalarEvolution::getUnionPredicate() const {
return Preds;
13033}

13035void PredicatedScalarEvolution::updateGeneration() {
// If the generation number wrapped recompute everything.
if (++Generation == 0) {
  for (auto &II : RewriteMap) {
    const SCEV *Rewritten = II.second.second;
    II.second = {Generation, SE.rewriteUsingPredicate(Rewritten, &L, Preds)};
  }
}
13043}

13045void PredicatedScalarEvolution::setNoOverflow(
  Value *V, SCEVWrapPredicate::IncrementWrapFlags Flags) {
const SCEV *Expr = getSCEV(V);
const auto *AR = cast<SCEVAddRecExpr>(Expr);

auto ImpliedFlags = SCEVWrapPredicate::getImpliedFlags(AR, SE);

// Clear the statically implied flags.
Flags = SCEVWrapPredicate::clearFlags(Flags, ImpliedFlags);
addPredicate(*SE.getWrapPredicate(AR, Flags));

auto II = FlagsMap.insert({V, Flags});
if (!II.second)
  II.first->second = SCEVWrapPredicate::setFlags(Flags, II.first->second);
13059}

13061bool PredicatedScalarEvolution::hasNoOverflow(
  Value *V, SCEVWrapPredicate::IncrementWrapFlags Flags) {
const SCEV *Expr = getSCEV(V);
const auto *AR = cast<SCEVAddRecExpr>(Expr);

Flags = SCEVWrapPredicate::clearFlags(
    Flags, SCEVWrapPredicate::getImpliedFlags(AR, SE));

auto II = FlagsMap.find(V);

if (II != FlagsMap.end())
  Flags = SCEVWrapPredicate::clearFlags(Flags, II->second);

return Flags == SCEVWrapPredicate::IncrementAnyWrap;
13075}

13077const SCEVAddRecExpr *PredicatedScalarEvolution::getAsAddRec(Value *V) {
const SCEV *Expr = this->getSCEV(V);
SmallPtrSet<const SCEVPredicate *, 4> NewPreds;
auto *New = SE.convertSCEVToAddRecWithPredicates(Expr, &L, NewPreds);

if (!New)
  return nullptr;

for (auto *P : NewPreds)
  Preds.add(P);

updateGeneration();
RewriteMap[SE.getSCEV(V)] = {Generation, New};
return New;
13091}

13093PredicatedScalarEvolution::PredicatedScalarEvolution(
  const PredicatedScalarEvolution &Init)
  : RewriteMap(Init.RewriteMap), SE(Init.SE), L(Init.L), Preds(Init.Preds),
    Generation(Init.Generation), BackedgeCount(Init.BackedgeCount) {
for (auto I : Init.FlagsMap)
  FlagsMap.insert(I);
13099}

13101void PredicatedScalarEvolution::print(raw_ostream &OS, unsigned Depth) const {
// For each block.
for (auto *BB : L.getBlocks())
  for (auto &I : *BB) {
    if (!SE.isSCEVable(I.getType()))
      continue;

    auto *Expr = SE.getSCEV(&I);
    auto II = RewriteMap.find(Expr);

    if (II == RewriteMap.end())
      continue;

    // Don't print things that are not interesting.
    if (II->second.second == Expr)
      continue;

    OS.indent(Depth) << "[PSE]" << I << ":\n";
    OS.indent(Depth + 2) << *Expr << "\n";
    OS.indent(Depth + 2) << "--> " << *II->second.second << "\n";
  }
13122}

13124// Match the mathematical pattern A - (A / B) * B, where A and B can be
13125// arbitrary expressions. Also match zext (trunc A to iB) to iY, which is used
13126// for URem with constant power-of-2 second operands.
13127// It's not always easy, as A and B can be folded (imagine A is X / 2, and B is
13128// 4, A / B becomes X / 8).
13129bool ScalarEvolution::matchURem(const SCEV *Expr, const SCEV *&LHS,
                              const SCEV *&RHS) {
// Try to match 'zext (trunc A to iB) to iY', which is used
// for URem with constant power-of-2 second operands. Make sure the size of
// the operand A matches the size of the whole expressions.
if (const auto *ZExt = dyn_cast<SCEVZeroExtendExpr>(Expr))
  if (const auto *Trunc = dyn_cast<SCEVTruncateExpr>(ZExt->getOperand(0))) {
    LHS = Trunc->getOperand();
    if (LHS->getType() != Expr->getType())
      LHS = getZeroExtendExpr(LHS, Expr->getType());
    RHS = getConstant(APInt(getTypeSizeInBits(Expr->getType()), 1)
                      << getTypeSizeInBits(Trunc->getType()));
    return true;
  }
const auto *Add = dyn_cast<SCEVAddExpr>(Expr);
if (Add == nullptr || Add->getNumOperands() != 2)
  return false;

const SCEV *A = Add->getOperand(1);
const auto *Mul = dyn_cast<SCEVMulExpr>(Add->getOperand(0));

if (Mul == nullptr)
  return false;

const auto MatchURemWithDivisor = [&](const SCEV *B) {
  // (SomeExpr + (-(SomeExpr / B) * B)).
  if (Expr == getURemExpr(A, B)) {
    LHS = A;
    RHS = B;
    return true;
  }
  return false;
};

// (SomeExpr + (-1 * (SomeExpr / B) * B)).
if (Mul->getNumOperands() == 3 && isa<SCEVConstant>(Mul->getOperand(0)))
  return MatchURemWithDivisor(Mul->getOperand(1)) ||
         MatchURemWithDivisor(Mul->getOperand(2));

// (SomeExpr + ((-SomeExpr / B) * B)) or (SomeExpr + ((SomeExpr / B) * -B)).
if (Mul->getNumOperands() == 2)
  return MatchURemWithDivisor(Mul->getOperand(1)) ||
         MatchURemWithDivisor(Mul->getOperand(0)) ||
         MatchURemWithDivisor(getNegativeSCEV(Mul->getOperand(1))) ||
         MatchURemWithDivisor(getNegativeSCEV(Mul->getOperand(0)));
return false;
13175}

13177const SCEV *
13178ScalarEvolution::computeSymbolicMaxBackedgeTakenCount(const Loop *L) {
SmallVector<BasicBlock*, 16> ExitingBlocks;
L->getExitingBlocks(ExitingBlocks);

// Form an expression for the maximum exit count possible for this loop. We
// merge the max and exact information to approximate a version of
// getConstantMaxBackedgeTakenCount which isn't restricted to just constants.
SmallVector<const SCEV*, 4> ExitCounts;
for (BasicBlock *ExitingBB : ExitingBlocks) {
  const SCEV *ExitCount = getExitCount(L, ExitingBB);
  if (isa<SCEVCouldNotCompute>(ExitCount))
    ExitCount = getExitCount(L, ExitingBB,
                                ScalarEvolution::ConstantMaximum);
  if (!isa<SCEVCouldNotCompute>(ExitCount)) {
    assert(DT.dominates(ExitingBB, L->getLoopLatch()) &&((DT.dominates(ExitingBB, L->getLoopLatch()) && "We should only have known counts for exiting blocks that "
 "dominate latch!") ? static_cast<void> (0) : __assert_fail
 ("DT.dominates(ExitingBB, L->getLoopLatch()) && \"We should only have known counts for exiting blocks that \" \"dominate latch!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 13194, __PRETTY_FUNCTION__))
           "We should only have known counts for exiting blocks that "((DT.dominates(ExitingBB, L->getLoopLatch()) && "We should only have known counts for exiting blocks that "
 "dominate latch!") ? static_cast<void> (0) : __assert_fail
 ("DT.dominates(ExitingBB, L->getLoopLatch()) && \"We should only have known counts for exiting blocks that \" \"dominate latch!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 13194, __PRETTY_FUNCTION__))
           "dominate latch!")((DT.dominates(ExitingBB, L->getLoopLatch()) && "We should only have known counts for exiting blocks that "
 "dominate latch!") ? static_cast<void> (0) : __assert_fail
 ("DT.dominates(ExitingBB, L->getLoopLatch()) && \"We should only have known counts for exiting blocks that \" \"dominate latch!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/lib/Analysis/ScalarEvolution.cpp"
, 13194, __PRETTY_FUNCTION__));
    ExitCounts.push_back(ExitCount);
  }
}
if (ExitCounts.empty())
  return getCouldNotCompute();
return getUMinFromMismatchedTypes(ExitCounts);
13201}

13203/// This rewriter is similar to SCEVParameterRewriter (it replaces SCEVUnknown
13204/// components following the Map (Value -> SCEV)), but skips AddRecExpr because
13205/// we cannot guarantee that the replacement is loop invariant in the loop of
13206/// the AddRec.
13207class SCEVLoopGuardRewriter : public SCEVRewriteVisitor<SCEVLoopGuardRewriter> {
ValueToSCEVMapTy &Map;

13210public:
SCEVLoopGuardRewriter(ScalarEvolution &SE, ValueToSCEVMapTy &M)
    : SCEVRewriteVisitor(SE), Map(M) {}

const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) { return Expr; }

const SCEV *visitUnknown(const SCEVUnknown *Expr) {
  auto I = Map.find(Expr->getValue());
  if (I == Map.end())
    return Expr;
  return I->second;
}
13222};

13224const SCEV *ScalarEvolution::applyLoopGuards(const SCEV *Expr, const Loop *L) {
auto CollectCondition = [&](ICmpInst::Predicate Predicate, const SCEV *LHS,
                            const SCEV *RHS, ValueToSCEVMapTy &RewriteMap) {
  if (!isa<SCEVUnknown>(LHS)) {
    std::swap(LHS, RHS);
    Predicate = CmpInst::getSwappedPredicate(Predicate);
  }

  // For now, limit to conditions that provide information about unknown
  // expressions.
  auto *LHSUnknown = dyn_cast<SCEVUnknown>(LHS);
  if (!LHSUnknown)
    return;

  // TODO: use information from more predicates.
  switch (Predicate) {
  case CmpInst::ICMP_ULT: {
    if (!containsAddRecurrence(RHS)) {
      const SCEV *Base = LHS;
      auto I = RewriteMap.find(LHSUnknown->getValue());
      if (I != RewriteMap.end())
        Base = I->second;

      RewriteMap[LHSUnknown->getValue()] =
          getUMinExpr(Base, getMinusSCEV(RHS, getOne(RHS->getType())));
    }
    break;
  }
  case CmpInst::ICMP_ULE: {
    if (!containsAddRecurrence(RHS)) {
      const SCEV *Base = LHS;
      auto I = RewriteMap.find(LHSUnknown->getValue());
      if (I != RewriteMap.end())
        Base = I->second;
      RewriteMap[LHSUnknown->getValue()] = getUMinExpr(Base, RHS);
    }
    break;
  }
  case CmpInst::ICMP_EQ:
    if (isa<SCEVConstant>(RHS))
      RewriteMap[LHSUnknown->getValue()] = RHS;
    break;
  case CmpInst::ICMP_NE:
    if (isa<SCEVConstant>(RHS) &&
        cast<SCEVConstant>(RHS)->getValue()->isNullValue())
      RewriteMap[LHSUnknown->getValue()] =
          getUMaxExpr(LHS, getOne(RHS->getType()));
    break;
  default:
    break;
  }
};
// Starting at the loop predecessor, climb up the predecessor chain, as long
// as there are predecessors that can be found that have unique successors
// leading to the original header.
// TODO: share this logic with isLoopEntryGuardedByCond.
ValueToSCEVMapTy RewriteMap;
for (std::pair<const BasicBlock *, const BasicBlock *> Pair(
         L->getLoopPredecessor(), L->getHeader());
     Pair.first; Pair = getPredecessorWithUniqueSuccessorForBB(Pair.first)) {

  const BranchInst *LoopEntryPredicate =
      dyn_cast<BranchInst>(Pair.first->getTerminator());
  if (!LoopEntryPredicate || LoopEntryPredicate->isUnconditional())
    continue;

  // TODO: use information from more complex conditions, e.g. AND expressions.
  auto *Cmp = dyn_cast<ICmpInst>(LoopEntryPredicate->getCondition());
  if (!Cmp)
    continue;

  auto Predicate = Cmp->getPredicate();
  if (LoopEntryPredicate->getSuccessor(1) == Pair.second)
    Predicate = CmpInst::getInversePredicate(Predicate);
  CollectCondition(Predicate, getSCEV(Cmp->getOperand(0)),
                   getSCEV(Cmp->getOperand(1)), RewriteMap);
}

// Also collect information from assumptions dominating the loop.
for (auto &AssumeVH : AC.assumptions()) {
  if (!AssumeVH)
    continue;
  auto *AssumeI = cast<CallInst>(AssumeVH);
  auto *Cmp = dyn_cast<ICmpInst>(AssumeI->getOperand(0));
  if (!Cmp || !DT.dominates(AssumeI, L->getHeader()))
    continue;
  CollectCondition(Cmp->getPredicate(), getSCEV(Cmp->getOperand(0)),
                   getSCEV(Cmp->getOperand(1)), RewriteMap);
}

if (RewriteMap.empty())
  return Expr;
SCEVLoopGuardRewriter Rewriter(*this, RewriteMap);
return Rewriter.visit(Expr);
13318}

←

/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h

→

1//===- llvm/Analysis/ScalarEvolutionExpressions.h - SCEV Exprs --*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the classes used to represent and build scalar expressions.
10//
11//===----------------------------------------------------------------------===//

13#ifndef LLVM_ANALYSIS_SCALAREVOLUTIONEXPRESSIONS_H
14#define LLVM_ANALYSIS_SCALAREVOLUTIONEXPRESSIONS_H

16#include "llvm/ADT/DenseMap.h"
17#include "llvm/ADT/FoldingSet.h"
18#include "llvm/ADT/SmallPtrSet.h"
19#include "llvm/ADT/SmallVector.h"
20#include "llvm/ADT/iterator_range.h"
21#include "llvm/Analysis/ScalarEvolution.h"
22#include "llvm/IR/Constants.h"
23#include "llvm/IR/Value.h"
24#include "llvm/IR/ValueHandle.h"
25#include "llvm/Support/Casting.h"
26#include "llvm/Support/ErrorHandling.h"
27#include <cassert>
28#include <cstddef>

30namespace llvm {

32class APInt;
33class Constant;
34class ConstantRange;
35class Loop;
36class Type;

enum SCEVTypes : unsigned short {
  // These should be ordered in terms of increasing complexity to make the
  // folders simpler.
  scConstant, scTruncate, scZeroExtend, scSignExtend, scAddExpr, scMulExpr,
  scUDivExpr, scAddRecExpr, scUMaxExpr, scSMaxExpr, scUMinExpr, scSMinExpr,
  scPtrToInt, scUnknown, scCouldNotCompute
};

/// This class represents a constant integer value.
class SCEVConstant : public SCEV {
  friend class ScalarEvolution;

  ConstantInt *V;

  SCEVConstant(const FoldingSetNodeIDRef ID, ConstantInt *v) :
    SCEV(ID, scConstant, 1), V(v) {}

public:
  ConstantInt *getValue() const { return V; }
  const APInt &getAPInt() const { return getValue()->getValue(); }

  Type *getType() const { return V->getType(); }

  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scConstant;
  }
};

inline unsigned short computeExpressionSize(ArrayRef<const SCEV *> Args) {
  APInt Size(16, 1);
  for (auto *Arg : Args)
    Size = Size.uadd_sat(APInt(16, Arg->getExpressionSize()));
  return (unsigned short)Size.getZExtValue();
}

/// This is the base class for unary cast operator classes.
class SCEVCastExpr : public SCEV {
protected:
  std::array<const SCEV *, 1> Operands;
  Type *Ty;

  SCEVCastExpr(const FoldingSetNodeIDRef ID, SCEVTypes SCEVTy, const SCEV *op,
               Type *ty);

public:
  const SCEV *getOperand() const { return Operands[0]; }
  const SCEV *getOperand(unsigned i) const {
    assert(i == 0 && "Operand index out of range!")((i == 0 && "Operand index out of range!") ? static_cast
<void> (0) : __assert_fail ("i == 0 && \"Operand index out of range!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h"
, 86, __PRETTY_FUNCTION__));
    return Operands[0];
  }
  using op_iterator = std::array<const SCEV *, 1>::const_iterator;
  using op_range = iterator_range<op_iterator>;

  op_range operands() const {
    return make_range(Operands.begin(), Operands.end());
  }
  size_t getNumOperands() const { return 1; }
  Type *getType() const { return Ty; }

  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scPtrToInt || S->getSCEVType() == scTruncate ||
           S->getSCEVType() == scZeroExtend ||
           S->getSCEVType() == scSignExtend;
  }
};

/// This class represents a cast from a pointer to a pointer-sized integer
/// value.
class SCEVPtrToIntExpr : public SCEVCastExpr {
  friend class ScalarEvolution;

  SCEVPtrToIntExpr(const FoldingSetNodeIDRef ID, const SCEV *Op, Type *ITy);

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scPtrToInt;
  }
};

/// This is the base class for unary integral cast operator classes.
class SCEVIntegralCastExpr : public SCEVCastExpr {
protected:
  SCEVIntegralCastExpr(const FoldingSetNodeIDRef ID, SCEVTypes SCEVTy,
                       const SCEV *op, Type *ty);

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scTruncate ||
           S->getSCEVType() == scZeroExtend ||
           S->getSCEVType() == scSignExtend;
  }
};

/// This class represents a truncation of an integer value to a
/// smaller integer value.
class SCEVTruncateExpr : public SCEVIntegralCastExpr {
  friend class ScalarEvolution;

  SCEVTruncateExpr(const FoldingSetNodeIDRef ID,
                   const SCEV *op, Type *ty);

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scTruncate;
  }
};

/// This class represents a zero extension of a small integer value
/// to a larger integer value.
class SCEVZeroExtendExpr : public SCEVIntegralCastExpr {
  friend class ScalarEvolution;

  SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID,
                     const SCEV *op, Type *ty);

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scZeroExtend;
  }
};

/// This class represents a sign extension of a small integer value
/// to a larger integer value.
class SCEVSignExtendExpr : public SCEVIntegralCastExpr {
  friend class ScalarEvolution;

  SCEVSignExtendExpr(const FoldingSetNodeIDRef ID,
                     const SCEV *op, Type *ty);

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scSignExtend;
  }
};

/// This node is a base class providing common functionality for
/// n'ary operators.
class SCEVNAryExpr : public SCEV {
protected:
  // Since SCEVs are immutable, ScalarEvolution allocates operand
  // arrays with its SCEVAllocator, so this class just needs a simple
  // pointer rather than a more elaborate vector-like data structure.
  // This also avoids the need for a non-trivial destructor.
  const SCEV *const *Operands;
  size_t NumOperands;

  SCEVNAryExpr(const FoldingSetNodeIDRef ID, enum SCEVTypes T,
               const SCEV *const *O, size_t N)
      : SCEV(ID, T, computeExpressionSize(makeArrayRef(O, N))), Operands(O),
        NumOperands(N) {}

public:
  size_t getNumOperands() const { return NumOperands; }

  const SCEV *getOperand(unsigned i) const {
    assert(i < NumOperands && "Operand index out of range!")((i < NumOperands && "Operand index out of range!"
) ? static_cast<void> (0) : __assert_fail ("i < NumOperands && \"Operand index out of range!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h"
, 200, __PRETTY_FUNCTION__));
    return Operands[i];
  }

  using op_iterator = const SCEV *const *;
  using op_range = iterator_range<op_iterator>;

  op_iterator op_begin() const { return Operands; }
  op_iterator op_end() const { return Operands + NumOperands; }
  op_range operands() const {
    return make_range(op_begin(), op_end());
  }

  Type *getType() const { return getOperand(0)->getType(); }

  NoWrapFlags getNoWrapFlags(NoWrapFlags Mask = NoWrapMask) const {
    return (NoWrapFlags)(SubclassData & Mask);
  }

  bool hasNoUnsignedWrap() const {
    return getNoWrapFlags(FlagNUW) != FlagAnyWrap;
  }

  bool hasNoSignedWrap() const {
    return getNoWrapFlags(FlagNSW) != FlagAnyWrap;
30
←
Assuming the condition is false→
31
←
Returning zero, which participates in a condition later→
  }

  bool hasNoSelfWrap() const {
    return getNoWrapFlags(FlagNW) != FlagAnyWrap;
45
←
Assuming the condition is true→
46
←
Returning the value 1, which participates in a condition later→
  }

  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scAddExpr || S->getSCEVType() == scMulExpr ||
           S->getSCEVType() == scSMaxExpr || S->getSCEVType() == scUMaxExpr ||
           S->getSCEVType() == scSMinExpr || S->getSCEVType() == scUMinExpr ||
           S->getSCEVType() == scAddRecExpr;
  }
};

/// This node is the base class for n'ary commutative operators.
class SCEVCommutativeExpr : public SCEVNAryExpr {
protected:
  SCEVCommutativeExpr(const FoldingSetNodeIDRef ID,
                      enum SCEVTypes T, const SCEV *const *O, size_t N)
    : SCEVNAryExpr(ID, T, O, N) {}

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scAddExpr || S->getSCEVType() == scMulExpr ||
           S->getSCEVType() == scSMaxExpr || S->getSCEVType() == scUMaxExpr ||
           S->getSCEVType() == scSMinExpr || S->getSCEVType() == scUMinExpr;
  }

  /// Set flags for a non-recurrence without clearing previously set flags.
  void setNoWrapFlags(NoWrapFlags Flags) {
    SubclassData |= Flags;
  }
};

/// This node represents an addition of some number of SCEVs.
class SCEVAddExpr : public SCEVCommutativeExpr {
  friend class ScalarEvolution;

  Type *Ty;

  SCEVAddExpr(const FoldingSetNodeIDRef ID, const SCEV *const *O, size_t N)
      : SCEVCommutativeExpr(ID, scAddExpr, O, N) {
    auto *FirstPointerTypedOp = find_if(operands(), [](const SCEV *Op) {
      return Op->getType()->isPointerTy();
    });
    if (FirstPointerTypedOp != operands().end())
      Ty = (*FirstPointerTypedOp)->getType();
    else
      Ty = getOperand(0)->getType();
  }

public:
  Type *getType() const { return Ty; }

  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scAddExpr;
  }
};

/// This node represents multiplication of some number of SCEVs.
class SCEVMulExpr : public SCEVCommutativeExpr {
  friend class ScalarEvolution;

  SCEVMulExpr(const FoldingSetNodeIDRef ID,
              const SCEV *const *O, size_t N)
    : SCEVCommutativeExpr(ID, scMulExpr, O, N) {}

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scMulExpr;
  }
};

/// This class represents a binary unsigned division operation.
class SCEVUDivExpr : public SCEV {
  friend class ScalarEvolution;

  std::array<const SCEV *, 2> Operands;

  SCEVUDivExpr(const FoldingSetNodeIDRef ID, const SCEV *lhs, const SCEV *rhs)
      : SCEV(ID, scUDivExpr, computeExpressionSize({lhs, rhs})) {
      Operands[0] = lhs;
      Operands[1] = rhs;
    }

public:
  const SCEV *getLHS() const { return Operands[0]; }
  const SCEV *getRHS() const { return Operands[1]; }
  size_t getNumOperands() const { return 2; }
  const SCEV *getOperand(unsigned i) const {
    assert((i == 0 || i == 1) && "Operand index out of range!")(((i == 0 || i == 1) && "Operand index out of range!"
) ? static_cast<void> (0) : __assert_fail ("(i == 0 || i == 1) && \"Operand index out of range!\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h"
, 319, __PRETTY_FUNCTION__));
    return i == 0 ? getLHS() : getRHS();
  }

  using op_iterator = std::array<const SCEV *, 2>::const_iterator;
  using op_range = iterator_range<op_iterator>;
  op_range operands() const {
    return make_range(Operands.begin(), Operands.end());
  }

  Type *getType() const {
    // In most cases the types of LHS and RHS will be the same, but in some
    // crazy cases one or the other may be a pointer. ScalarEvolution doesn't
    // depend on the type for correctness, but handling types carefully can
    // avoid extra casts in the SCEVExpander. The LHS is more likely to be
    // a pointer type than the RHS, so use the RHS' type here.
    return getRHS()->getType();
  }

  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scUDivExpr;
  }
};

/// This node represents a polynomial recurrence on the trip count
/// of the specified loop.  This is the primary focus of the
/// ScalarEvolution framework; all the other SCEV subclasses are
/// mostly just supporting infrastructure to allow SCEVAddRecExpr
/// expressions to be created and analyzed.
///
/// All operands of an AddRec are required to be loop invariant.
///
class SCEVAddRecExpr : public SCEVNAryExpr {
  friend class ScalarEvolution;

  const Loop *L;

  SCEVAddRecExpr(const FoldingSetNodeIDRef ID,
                 const SCEV *const *O, size_t N, const Loop *l)
    : SCEVNAryExpr(ID, scAddRecExpr, O, N), L(l) {}

public:
  const SCEV *getStart() const { return Operands[0]; }
  const Loop *getLoop() const { return L; }

  /// Constructs and returns the recurrence indicating how much this
  /// expression steps by.  If this is a polynomial of degree N, it
  /// returns a chrec of degree N-1.  We cannot determine whether
  /// the step recurrence has self-wraparound.
  const SCEV *getStepRecurrence(ScalarEvolution &SE) const {
    if (isAffine()) return getOperand(1);
    return SE.getAddRecExpr(SmallVector<const SCEV *, 3>(op_begin()+1,
                                                         op_end()),
                            getLoop(), FlagAnyWrap);
  }

  /// Return true if this represents an expression A + B*x where A
  /// and B are loop invariant values.
  bool isAffine() const {
    // We know that the start value is invariant.  This expression is thus
    // affine iff the step is also invariant.
    return getNumOperands() == 2;
  }

  /// Return true if this represents an expression A + B*x + C*x^2
  /// where A, B and C are loop invariant values.  This corresponds
  /// to an addrec of the form {L,+,M,+,N}
  bool isQuadratic() const {
    return getNumOperands() == 3;
  }

  /// Set flags for a recurrence without clearing any previously set flags.
  /// For AddRec, either NUW or NSW implies NW. Keep track of this fact here
  /// to make it easier to propagate flags.
  void setNoWrapFlags(NoWrapFlags Flags) {
    if (Flags & (FlagNUW | FlagNSW))
      Flags = ScalarEvolution::setFlags(Flags, FlagNW);
    SubclassData |= Flags;
  }

  /// Return the value of this chain of recurrences at the specified
  /// iteration number.
  const SCEV *evaluateAtIteration(const SCEV *It, ScalarEvolution &SE) const;

  /// Return the number of iterations of this loop that produce
  /// values in the specified constant range.  Another way of
  /// looking at this is that it returns the first iteration number
  /// where the value is not in the condition, thus computing the
  /// exit count.  If the iteration count can't be computed, an
  /// instance of SCEVCouldNotCompute is returned.
  const SCEV *getNumIterationsInRange(const ConstantRange &Range,
                                      ScalarEvolution &SE) const;

  /// Return an expression representing the value of this expression
  /// one iteration of the loop ahead.
  const SCEVAddRecExpr *getPostIncExpr(ScalarEvolution &SE) const;

  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scAddRecExpr;
  }
};

/// This node is the base class min/max selections.
class SCEVMinMaxExpr : public SCEVCommutativeExpr {
  friend class ScalarEvolution;

  static bool isMinMaxType(enum SCEVTypes T) {
    return T == scSMaxExpr || T == scUMaxExpr || T == scSMinExpr ||
           T == scUMinExpr;
  }

protected:
  /// Note: Constructing subclasses via this constructor is allowed
  SCEVMinMaxExpr(const FoldingSetNodeIDRef ID, enum SCEVTypes T,
                 const SCEV *const *O, size_t N)
      : SCEVCommutativeExpr(ID, T, O, N) {
    assert(isMinMaxType(T))((isMinMaxType(T)) ? static_cast<void> (0) : __assert_fail
 ("isMinMaxType(T)", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h"
, 437, __PRETTY_FUNCTION__));
    // Min and max never overflow
    setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW));
  }

public:
  static bool classof(const SCEV *S) {
    return isMinMaxType(S->getSCEVType());
  }

  static enum SCEVTypes negate(enum SCEVTypes T) {
    switch (T) {
    case scSMaxExpr:
      return scSMinExpr;
    case scSMinExpr:
      return scSMaxExpr;
    case scUMaxExpr:
      return scUMinExpr;
    case scUMinExpr:
      return scUMaxExpr;
    default:
      llvm_unreachable("Not a min or max SCEV type!")::llvm::llvm_unreachable_internal("Not a min or max SCEV type!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h"
, 458);
    }
  }
};

/// This class represents a signed maximum selection.
class SCEVSMaxExpr : public SCEVMinMaxExpr {
  friend class ScalarEvolution;

  SCEVSMaxExpr(const FoldingSetNodeIDRef ID, const SCEV *const *O, size_t N)
      : SCEVMinMaxExpr(ID, scSMaxExpr, O, N) {}

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scSMaxExpr;
  }
};

/// This class represents an unsigned maximum selection.
class SCEVUMaxExpr : public SCEVMinMaxExpr {
  friend class ScalarEvolution;

  SCEVUMaxExpr(const FoldingSetNodeIDRef ID, const SCEV *const *O, size_t N)
      : SCEVMinMaxExpr(ID, scUMaxExpr, O, N) {}

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scUMaxExpr;
  }
};

/// This class represents a signed minimum selection.
class SCEVSMinExpr : public SCEVMinMaxExpr {
  friend class ScalarEvolution;

  SCEVSMinExpr(const FoldingSetNodeIDRef ID, const SCEV *const *O, size_t N)
      : SCEVMinMaxExpr(ID, scSMinExpr, O, N) {}

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scSMinExpr;
  }
};

/// This class represents an unsigned minimum selection.
class SCEVUMinExpr : public SCEVMinMaxExpr {
  friend class ScalarEvolution;

  SCEVUMinExpr(const FoldingSetNodeIDRef ID, const SCEV *const *O, size_t N)
      : SCEVMinMaxExpr(ID, scUMinExpr, O, N) {}

public:
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scUMinExpr;
  }
};

/// This means that we are dealing with an entirely unknown SCEV
/// value, and only represent it as its LLVM Value.  This is the
/// "bottom" value for the analysis.
class SCEVUnknown final : public SCEV, private CallbackVH {
  friend class ScalarEvolution;

  /// The parent ScalarEvolution value. This is used to update the
  /// parent's maps when the value associated with a SCEVUnknown is
  /// deleted or RAUW'd.
  ScalarEvolution *SE;

  /// The next pointer in the linked list of all SCEVUnknown
  /// instances owned by a ScalarEvolution.
  SCEVUnknown *Next;

  SCEVUnknown(const FoldingSetNodeIDRef ID, Value *V,
              ScalarEvolution *se, SCEVUnknown *next) :
    SCEV(ID, scUnknown, 1), CallbackVH(V), SE(se), Next(next) {}

  // Implement CallbackVH.
  void deleted() override;
  void allUsesReplacedWith(Value *New) override;

public:
  Value *getValue() const { return getValPtr(); }

  /// @{
  /// Test whether this is a special constant representing a type
  /// size, alignment, or field offset in a target-independent
  /// manner, and hasn't happened to have been folded with other
  /// operations into something unrecognizable. This is mainly only
  /// useful for pretty-printing and other situations where it isn't
  /// absolutely required for these to succeed.
  bool isSizeOf(Type *&AllocTy) const;
  bool isAlignOf(Type *&AllocTy) const;
  bool isOffsetOf(Type *&STy, Constant *&FieldNo) const;
  /// @}

  Type *getType() const { return getValPtr()->getType(); }

  /// Methods for support type inquiry through isa, cast, and dyn_cast:
  static bool classof(const SCEV *S) {
    return S->getSCEVType() == scUnknown;
  }
};

/// This class defines a simple visitor class that may be used for
/// various SCEV analysis purposes.
template<typename SC, typename RetVal=void>
struct SCEVVisitor {
  RetVal visit(const SCEV *S) {
    switch (S->getSCEVType()) {
    case scConstant:
      return ((SC*)this)->visitConstant((const SCEVConstant*)S);
    case scPtrToInt:
      return ((SC *)this)->visitPtrToIntExpr((const SCEVPtrToIntExpr *)S);
    case scTruncate:
      return ((SC*)this)->visitTruncateExpr((const SCEVTruncateExpr*)S);
    case scZeroExtend:
      return ((SC*)this)->visitZeroExtendExpr((const SCEVZeroExtendExpr*)S);
    case scSignExtend:
      return ((SC*)this)->visitSignExtendExpr((const SCEVSignExtendExpr*)S);
    case scAddExpr:
      return ((SC*)this)->visitAddExpr((const SCEVAddExpr*)S);
    case scMulExpr:
      return ((SC*)this)->visitMulExpr((const SCEVMulExpr*)S);
    case scUDivExpr:
      return ((SC*)this)->visitUDivExpr((const SCEVUDivExpr*)S);
    case scAddRecExpr:
      return ((SC*)this)->visitAddRecExpr((const SCEVAddRecExpr*)S);
    case scSMaxExpr:
      return ((SC*)this)->visitSMaxExpr((const SCEVSMaxExpr*)S);
    case scUMaxExpr:
      return ((SC*)this)->visitUMaxExpr((const SCEVUMaxExpr*)S);
    case scSMinExpr:
      return ((SC *)this)->visitSMinExpr((const SCEVSMinExpr *)S);
    case scUMinExpr:
      return ((SC *)this)->visitUMinExpr((const SCEVUMinExpr *)S);
    case scUnknown:
      return ((SC*)this)->visitUnknown((const SCEVUnknown*)S);
    case scCouldNotCompute:
      return ((SC*)this)->visitCouldNotCompute((const SCEVCouldNotCompute*)S);
    }
    llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h"
, 602);
  }

  RetVal visitCouldNotCompute(const SCEVCouldNotCompute *S) {
    llvm_unreachable("Invalid use of SCEVCouldNotCompute!")::llvm::llvm_unreachable_internal("Invalid use of SCEVCouldNotCompute!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h"
, 606);
  }
};

/// Visit all nodes in the expression tree using worklist traversal.
///
/// Visitor implements:
///   // return true to follow this node.
///   bool follow(const SCEV *S);
///   // return true to terminate the search.
///   bool isDone();
template<typename SV>
class SCEVTraversal {
  SV &Visitor;
  SmallVector<const SCEV *, 8> Worklist;
  SmallPtrSet<const SCEV *, 8> Visited;

  void push(const SCEV *S) {
    if (Visited.insert(S).second && Visitor.follow(S))
      Worklist.push_back(S);
  }

public:
  SCEVTraversal(SV& V): Visitor(V) {}

  void visitAll(const SCEV *Root) {
    push(Root);
    while (!Worklist.empty() && !Visitor.isDone()) {
      const SCEV *S = Worklist.pop_back_val();

      switch (S->getSCEVType()) {
      case scConstant:
      case scUnknown:
        continue;
      case scPtrToInt:
      case scTruncate:
      case scZeroExtend:
      case scSignExtend:
        push(cast<SCEVCastExpr>(S)->getOperand());
        continue;
      case scAddExpr:
      case scMulExpr:
      case scSMaxExpr:
      case scUMaxExpr:
      case scSMinExpr:
      case scUMinExpr:
      case scAddRecExpr:
        for (const auto *Op : cast<SCEVNAryExpr>(S)->operands())
          push(Op);
        continue;
      case scUDivExpr: {
        const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S);
        push(UDiv->getLHS());
        push(UDiv->getRHS());
        continue;
      }
      case scCouldNotCompute:
        llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!")::llvm::llvm_unreachable_internal("Attempt to use a SCEVCouldNotCompute object!"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h"
, 663);
      }
      llvm_unreachable("Unknown SCEV kind!")::llvm::llvm_unreachable_internal("Unknown SCEV kind!", "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h"
, 665);
    }
  }
};

/// Use SCEVTraversal to visit all nodes in the given expression tree.
template<typename SV>
void visitAll(const SCEV *Root, SV& Visitor) {
  SCEVTraversal<SV> T(Visitor);
  T.visitAll(Root);
}

/// Return true if any node in \p Root satisfies the predicate \p Pred.
template <typename PredTy>
bool SCEVExprContains(const SCEV *Root, PredTy Pred) {
  struct FindClosure {
    bool Found = false;
    PredTy Pred;

    FindClosure(PredTy Pred) : Pred(Pred) {}

    bool follow(const SCEV *S) {
      if (!Pred(S))
        return true;

      Found = true;
      return false;
    }

    bool isDone() const { return Found; }
  };

  FindClosure FC(Pred);
  visitAll(Root, FC);
  return FC.Found;
}

/// This visitor recursively visits a SCEV expression and re-writes it.
/// The result from each visit is cached, so it will return the same
/// SCEV for the same input.
template<typename SC>
class SCEVRewriteVisitor : public SCEVVisitor<SC, const SCEV *> {
protected:
  ScalarEvolution &SE;
  // Memoize the result of each visit so that we only compute once for
  // the same input SCEV. This is to avoid redundant computations when
  // a SCEV is referenced by multiple SCEVs. Without memoization, this
  // visit algorithm would have exponential time complexity in the worst
  // case, causing the compiler to hang on certain tests.
  DenseMap<const SCEV *, const SCEV *> RewriteResults;

public:
  SCEVRewriteVisitor(ScalarEvolution &SE) : SE(SE) {}

  const SCEV *visit(const SCEV *S) {
    auto It = RewriteResults.find(S);
    if (It != RewriteResults.end())
      return It->second;
    auto* Visited = SCEVVisitor<SC, const SCEV *>::visit(S);
    auto Result = RewriteResults.try_emplace(S, Visited);
    assert(Result.second && "Should insert a new entry")((Result.second && "Should insert a new entry") ? static_cast
<void> (0) : __assert_fail ("Result.second && \"Should insert a new entry\""
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h"
, 725, __PRETTY_FUNCTION__));
    return Result.first->second;
  }

  const SCEV *visitConstant(const SCEVConstant *Constant) {
    return Constant;
  }

  const SCEV *visitPtrToIntExpr(const SCEVPtrToIntExpr *Expr) {
    const SCEV *Operand = ((SC *)this)->visit(Expr->getOperand());
    return Operand == Expr->getOperand()
               ? Expr
               : SE.getPtrToIntExpr(Operand, Expr->getType());
  }

  const SCEV *visitTruncateExpr(const SCEVTruncateExpr *Expr) {
    const SCEV *Operand = ((SC*)this)->visit(Expr->getOperand());
    return Operand == Expr->getOperand()
               ? Expr
               : SE.getTruncateExpr(Operand, Expr->getType());
  }

  const SCEV *visitZeroExtendExpr(const SCEVZeroExtendExpr *Expr) {
    const SCEV *Operand = ((SC*)this)->visit(Expr->getOperand());
    return Operand == Expr->getOperand()
               ? Expr
               : SE.getZeroExtendExpr(Operand, Expr->getType());
  }

  const SCEV *visitSignExtendExpr(const SCEVSignExtendExpr *Expr) {
    const SCEV *Operand = ((SC*)this)->visit(Expr->getOperand());
    return Operand == Expr->getOperand()
               ? Expr
               : SE.getSignExtendExpr(Operand, Expr->getType());
  }

  const SCEV *visitAddExpr(const SCEVAddExpr *Expr) {
    SmallVector<const SCEV *, 2> Operands;
    bool Changed = false;
    for (auto *Op : Expr->operands()) {
      Operands.push_back(((SC*)this)->visit(Op));
      Changed |= Op != Operands.back();
    }
    return !Changed ? Expr : SE.getAddExpr(Operands);
  }

  const SCEV *visitMulExpr(const SCEVMulExpr *Expr) {
    SmallVector<const SCEV *, 2> Operands;
    bool Changed = false;
    for (auto *Op : Expr->operands()) {
      Operands.push_back(((SC*)this)->visit(Op));
      Changed |= Op != Operands.back();
    }
    return !Changed ? Expr : SE.getMulExpr(Operands);
  }

  const SCEV *visitUDivExpr(const SCEVUDivExpr *Expr) {
    auto *LHS = ((SC *)this)->visit(Expr->getLHS());
    auto *RHS = ((SC *)this)->visit(Expr->getRHS());
    bool Changed = LHS != Expr->getLHS() || RHS != Expr->getRHS();
    return !Changed ? Expr : SE.getUDivExpr(LHS, RHS);
  }

  const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
    SmallVector<const SCEV *, 2> Operands;
    bool Changed = false;
    for (auto *Op : Expr->operands()) {
      Operands.push_back(((SC*)this)->visit(Op));
      Changed |= Op != Operands.back();
    }
    return !Changed ? Expr
                    : SE.getAddRecExpr(Operands, Expr->getLoop(),
                                       Expr->getNoWrapFlags());
  }

  const SCEV *visitSMaxExpr(const SCEVSMaxExpr *Expr) {
    SmallVector<const SCEV *, 2> Operands;
    bool Changed = false;
    for (auto *Op : Expr->operands()) {
      Operands.push_back(((SC *)this)->visit(Op));
      Changed |= Op != Operands.back();
    }
    return !Changed ? Expr : SE.getSMaxExpr(Operands);
  }

  const SCEV *visitUMaxExpr(const SCEVUMaxExpr *Expr) {
    SmallVector<const SCEV *, 2> Operands;
    bool Changed = false;
    for (auto *Op : Expr->operands()) {
      Operands.push_back(((SC*)this)->visit(Op));
      Changed |= Op != Operands.back();
    }
    return !Changed ? Expr : SE.getUMaxExpr(Operands);
  }

  const SCEV *visitSMinExpr(const SCEVSMinExpr *Expr) {
    SmallVector<const SCEV *, 2> Operands;
    bool Changed = false;
    for (auto *Op : Expr->operands()) {
      Operands.push_back(((SC *)this)->visit(Op));
      Changed |= Op != Operands.back();
    }
    return !Changed ? Expr : SE.getSMinExpr(Operands);
  }

  const SCEV *visitUMinExpr(const SCEVUMinExpr *Expr) {
    SmallVector<const SCEV *, 2> Operands;
    bool Changed = false;
    for (auto *Op : Expr->operands()) {
      Operands.push_back(((SC *)this)->visit(Op));
      Changed |= Op != Operands.back();
    }
    return !Changed ? Expr : SE.getUMinExpr(Operands);
  }

  const SCEV *visitUnknown(const SCEVUnknown *Expr) {
    return Expr;
  }

  const SCEV *visitCouldNotCompute(const SCEVCouldNotCompute *Expr) {
    return Expr;
  }
};

using ValueToValueMap = DenseMap<const Value *, Value *>;
using ValueToSCEVMapTy = DenseMap<const Value *, const SCEV *>;

/// The SCEVParameterRewriter takes a scalar evolution expression and updates
/// the SCEVUnknown components following the Map (Value -> SCEV).
class SCEVParameterRewriter : public SCEVRewriteVisitor<SCEVParameterRewriter> {
public:
  static const SCEV *rewrite(const SCEV *Scev, ScalarEvolution &SE,
                             ValueToSCEVMapTy &Map) {
    SCEVParameterRewriter Rewriter(SE, Map);
    return Rewriter.visit(Scev);
  }

  SCEVParameterRewriter(ScalarEvolution &SE, ValueToSCEVMapTy &M)
      : SCEVRewriteVisitor(SE), Map(M) {}

  const SCEV *visitUnknown(const SCEVUnknown *Expr) {
    auto I = Map.find(Expr->getValue());
    if (I == Map.end())
      return Expr;
    return I->second;
  }

private:
  ValueToSCEVMapTy &Map;
};

using LoopToScevMapT = DenseMap<const Loop *, const SCEV *>;

/// The SCEVLoopAddRecRewriter takes a scalar evolution expression and applies
/// the Map (Loop -> SCEV) to all AddRecExprs.
class SCEVLoopAddRecRewriter
    : public SCEVRewriteVisitor<SCEVLoopAddRecRewriter> {
public:
  SCEVLoopAddRecRewriter(ScalarEvolution &SE, LoopToScevMapT &M)
      : SCEVRewriteVisitor(SE), Map(M) {}

  static const SCEV *rewrite(const SCEV *Scev, LoopToScevMapT &Map,
                             ScalarEvolution &SE) {
    SCEVLoopAddRecRewriter Rewriter(SE, Map);
    return Rewriter.visit(Scev);
  }

  const SCEV *visitAddRecExpr(const SCEVAddRecExpr *Expr) {
    SmallVector<const SCEV *, 2> Operands;
    for (const SCEV *Op : Expr->operands())
      Operands.push_back(visit(Op));

    const Loop *L = Expr->getLoop();
    const SCEV *Res = SE.getAddRecExpr(Operands, L, Expr->getNoWrapFlags());

    if (0 == Map.count(L))
      return Res;

    const SCEVAddRecExpr *Rec = cast<SCEVAddRecExpr>(Res);
    return Rec->evaluateAtIteration(Map[L], SE);
  }

private:
  LoopToScevMapT &Map;
};

911} // end namespace llvm

913#endif // LLVM_ANALYSIS_SCALAREVOLUTIONEXPRESSIONS_H

←

/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/ADT/Optional.h

1//===- Optional.h - Simple variant for passing optional values --*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9//  This file provides Optional, a template class modeled in the spirit of
10//  OCaml's 'opt' variant.  The idea is to strongly type whether or not
11//  a value can be optional.
12//
13//===----------------------------------------------------------------------===//
14 
15#ifndef LLVM_ADT_OPTIONAL_H
16#define LLVM_ADT_OPTIONAL_H
17 
18#include "llvm/ADT/None.h"
19#include "llvm/Support/Compiler.h"
20#include "llvm/Support/type_traits.h"
21#include <cassert>
22#include <memory>
23#include <new>
24#include <utility>
25 
26namespace llvm {
27 
28class raw_ostream;
29 
30namespace optional_detail {
31 
32struct in_place_t {};
33 
34/// Storage for any type.
35template <typename T, bool = is_trivially_copyable<T>::value>
36class OptionalStorage {
37  union {
38    char empty;
39    T value;
40  };
41  bool hasVal;
42 
43public:
44  ~OptionalStorage() { reset(); }
45 
46  constexpr OptionalStorage() noexcept : empty(), hasVal(false) {}
47 
48  constexpr OptionalStorage(OptionalStorage const &other) : OptionalStorage() {
49    if (other.hasValue()) {
50      emplace(other.value);
51    }
52  }
53  constexpr OptionalStorage(OptionalStorage &&other) : OptionalStorage() {
54    if (other.hasValue()) {
55      emplace(std::move(other.value));
56    }
57  }
58 
59  template <class... Args>
60  constexpr explicit OptionalStorage(in_place_t, Args &&... args)
61      : value(std::forward<Args>(args)...), hasVal(true) {}
62 
63  void reset() noexcept {
64    if (hasVal) {
65      value.~T();
66      hasVal = false;
67    }
68  }
69 
70  constexpr bool hasValue() const noexcept { return hasVal; }
71 
72  T &getValue() LLVM_LVALUE_FUNCTION& noexcept {
73    assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/ADT/Optional.h"
, 73, __PRETTY_FUNCTION__));
74    return value;
75  }
76  constexpr T const &getValue() const LLVM_LVALUE_FUNCTION& noexcept {
77    assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/ADT/Optional.h"
, 77, __PRETTY_FUNCTION__));
78    return value;
79  }
80#if LLVM_HAS_RVALUE_REFERENCE_THIS1
81  T &&getValue() && noexcept {
82    assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/ADT/Optional.h"
, 82, __PRETTY_FUNCTION__));
83    return std::move(value);
84  }
85#endif
86 
87  template <class... Args> void emplace(Args &&... args) {
88    reset();
89    ::new ((void *)std::addressof(value)) T(std::forward<Args>(args)...);
90    hasVal = true;
91  }
92 
93  OptionalStorage &operator=(T const &y) {
94    if (hasValue()) {
95      value = y;
96    } else {
97      ::new ((void *)std::addressof(value)) T(y);
98      hasVal = true;
99    }
100    return *this;
101  }
102  OptionalStorage &operator=(T &&y) {
103    if (hasValue()) {
104      value = std::move(y);
105    } else {
106      ::new ((void *)std::addressof(value)) T(std::move(y));
107      hasVal = true;
108    }
109    return *this;
110  }
111 
112  OptionalStorage &operator=(OptionalStorage const &other) {
113    if (other.hasValue()) {
114      if (hasValue()) {
115        value = other.value;
116      } else {
117        ::new ((void *)std::addressof(value)) T(other.value);
118        hasVal = true;
119      }
120    } else {
121      reset();
122    }
123    return *this;
124  }
125 
126  OptionalStorage &operator=(OptionalStorage &&other) {
127    if (other.hasValue()) {
128      if (hasValue()) {
129        value = std::move(other.value);
130      } else {
131        ::new ((void *)std::addressof(value)) T(std::move(other.value));
132        hasVal = true;
133      }
134    } else {
135      reset();
136    }
137    return *this;
138  }
139};
140 
141template <typename T> class OptionalStorage<T, true> {
142  union {
143    char empty;
144    T value;
145  };
146  bool hasVal = false;
147 
148public:
149  ~OptionalStorage() = default;
150 
151  constexpr OptionalStorage() noexcept : empty{} {}
152 
153  constexpr OptionalStorage(OptionalStorage const &other) = default;
154  constexpr OptionalStorage(OptionalStorage &&other) = default;
155 
156  OptionalStorage &operator=(OptionalStorage const &other) = default;
157  OptionalStorage &operator=(OptionalStorage &&other) = default;
158 
159  template <class... Args>
160  constexpr explicit OptionalStorage(in_place_t, Args &&... args)
161      : value(std::forward<Args>(args)...), hasVal(true) {}
162 
163  void reset() noexcept {
164    if (hasVal) {
165      value.~T();
166      hasVal = false;
167    }
168  }
169 
170  constexpr bool hasValue() const noexcept { return hasVal; }
37
←
Returning the value 1, which participates in a condition later→
171 
172  T &getValue() LLVM_LVALUE_FUNCTION& noexcept {
173    assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/ADT/Optional.h"
, 173, __PRETTY_FUNCTION__));
174    return value;
175  }
176  constexpr T const &getValue() const LLVM_LVALUE_FUNCTION& noexcept {
177    assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/ADT/Optional.h"
, 177, __PRETTY_FUNCTION__));
178    return value;
179  }
180#if LLVM_HAS_RVALUE_REFERENCE_THIS1
181  T &&getValue() && noexcept {
182    assert(hasVal)((hasVal) ? static_cast<void> (0) : __assert_fail ("hasVal"
, "/build/llvm-toolchain-snapshot-12~++20201124111112+7b5254223ac/llvm/include/llvm/ADT/Optional.h"
, 182, __PRETTY_FUNCTION__));
183    return std::move(value);
184  }
185#endif
186 
187  template <class... Args> void emplace(Args &&... args) {
188    reset();
189    ::new ((void *)std::addressof(value)) T(std::forward<Args>(args)...);
190    hasVal = true;
191  }
192 
193  OptionalStorage &operator=(T const &y) {
194    if (hasValue()) {
195      value = y;
196    } else {
197      ::new ((void *)std::addressof(value)) T(y);
198      hasVal = true;
199    }
200    return *this;
201  }
202  OptionalStorage &operator=(T &&y) {
203    if (hasValue()) {
204      value = std::move(y);
205    } else {
206      ::new ((void *)std::addressof(value)) T(std::move(y));
207      hasVal = true;
208    }
209    return *this;
210  }
211};
212 
213} // namespace optional_detail
214 
215template <typename T> class Optional {
216  optional_detail::OptionalStorage<T> Storage;
217 
218public:
219  using value_type = T;
220 
221  constexpr Optional() {}
222  constexpr Optional(NoneType) {}
223 
224  constexpr Optional(const T &y) : Storage(optional_detail::in_place_t{}, y) {}
225  constexpr Optional(const Optional &O) = default;
226 
227  constexpr Optional(T &&y)
228      : Storage(optional_detail::in_place_t{}, std::move(y)) {}
229  constexpr Optional(Optional &&O) = default;
230 
231  Optional &operator=(T &&y) {
232    Storage = std::move(y);
233    return *this;
234  }
235  Optional &operator=(Optional &&O) = default;
236 
237  /// Create a new object by constructing it in place with the given arguments.
238  template <typename... ArgTypes> void emplace(ArgTypes &&... Args) {
239    Storage.emplace(std::forward<ArgTypes>(Args)...);
240  }
241 
242  static constexpr Optional create(const T *y) {
243    return y ? Optional(*y) : Optional();
244  }
245 
246  Optional &operator=(const T &y) {
247    Storage = y;
248    return *this;
249  }
250  Optional &operator=(const Optional &O) = default;
251 
252  void reset() { Storage.reset(); }
253 
254  constexpr const T *getPointer() const { return &Storage.getValue(); }
255  T *getPointer() { return &Storage.getValue(); }
256  constexpr const T &getValue() const LLVM_LVALUE_FUNCTION& {
257    return Storage.getValue();
258  }
259  T &getValue() LLVM_LVALUE_FUNCTION& { return Storage.getValue(); }
260 
261  constexpr explicit operator bool() const { return hasValue(); }
35
←
Calling 'Optional::hasValue'→
40
←
Returning from 'Optional::hasValue'→
41
←
Returning the value 1, which participates in a condition later→
262  constexpr bool hasValue() const { return Storage.hasValue(); }
36
←
Calling 'OptionalStorage::hasValue'→
38
←
Returning from 'OptionalStorage::hasValue'→
39
←
Returning the value 1, which participates in a condition later→
263  constexpr const T *operator->() const { return getPointer(); }
264  T *operator->() { return getPointer(); }
265  constexpr const T &operator*() const LLVM_LVALUE_FUNCTION& {
266    return getValue();
267  }
268  T &operator*() LLVM_LVALUE_FUNCTION& { return getValue(); }
269 
270  template <typename U>
271  constexpr T getValueOr(U &&value) const LLVM_LVALUE_FUNCTION& {
272    return hasValue() ? getValue() : std::forward<U>(value);
273  }
274 
275  /// Apply a function to the value if present; otherwise return None.
276  template <class Function>
277  auto map(const Function &F) const LLVM_LVALUE_FUNCTION&
278      -> Optional<decltype(F(getValue()))> {
279    if (*this) return F(getValue());
280    return None;
281  }
282 
283#if LLVM_HAS_RVALUE_REFERENCE_THIS1
284  T &&getValue() && { return std::move(Storage.getValue()); }
285  T &&operator*() && { return std::move(Storage.getValue()); }
286 
287  template <typename U>
288  T getValueOr(U &&value) && {
289    return hasValue() ? std::move(getValue()) : std::forward<U>(value);
290  }
291 
292  /// Apply a function to the value if present; otherwise return None.
293  template <class Function>
294  auto map(const Function &F) &&
295      -> Optional<decltype(F(std::move(*this).getValue()))> {
296    if (*this) return F(std::move(*this).getValue());
297    return None;
298  }
299#endif
300};
301 
302template <typename T, typename U>
303constexpr bool operator==(const Optional<T> &X, const Optional<U> &Y) {
304  if (X && Y)
305    return *X == *Y;
306  return X.hasValue() == Y.hasValue();
307}
308 
309template <typename T, typename U>
310constexpr bool operator!=(const Optional<T> &X, const Optional<U> &Y) {
311  return !(X == Y);
312}
313 
314template <typename T, typename U>
315constexpr bool operator<(const Optional<T> &X, const Optional<U> &Y) {
316  if (X && Y)
317    return *X < *Y;
318  return X.hasValue() < Y.hasValue();
319}
320 
321template <typename T, typename U>
322constexpr bool operator<=(const Optional<T> &X, const Optional<U> &Y) {
323  return !(Y < X);
324}
325 
326template <typename T, typename U>
327constexpr bool operator>(const Optional<T> &X, const Optional<U> &Y) {
328  return Y < X;
329}
330 
331template <typename T, typename U>
332constexpr bool operator>=(const Optional<T> &X, const Optional<U> &Y) {
333  return !(X < Y);
334}
335 
336template <typename T>
337constexpr bool operator==(const Optional<T> &X, NoneType) {
338  return !X;
339}
340 
341template <typename T>
342constexpr bool operator==(NoneType, const Optional<T> &X) {
343  return X == None;
344}
345 
346template <typename T>
347constexpr bool operator!=(const Optional<T> &X, NoneType) {
348  return !(X == None);
349}
350 
351template <typename T>
352constexpr bool operator!=(NoneType, const Optional<T> &X) {
353  return X != None;
354}
355 
356template <typename T> constexpr bool operator<(const Optional<T> &X, NoneType) {
357  return false;
358}
359 
360template <typename T> constexpr bool operator<(NoneType, const Optional<T> &X) {
361  return X.hasValue();
362}
363 
364template <typename T>
365constexpr bool operator<=(const Optional<T> &X, NoneType) {
366  return !(None < X);
367}
368 
369template <typename T>
370constexpr bool operator<=(NoneType, const Optional<T> &X) {
371  return !(X < None);
372}
373 
374template <typename T> constexpr bool operator>(const Optional<T> &X, NoneType) {
375  return None < X;
376}
377 
378template <typename T> constexpr bool operator>(NoneType, const Optional<T> &X) {
379  return X < None;
380}
381 
382template <typename T>
383constexpr bool operator>=(const Optional<T> &X, NoneType) {
384  return None <= X;
385}
386 
387template <typename T>
388constexpr bool operator>=(NoneType, const Optional<T> &X) {
389  return X <= None;
390}
391 
392template <typename T>
393constexpr bool operator==(const Optional<T> &X, const T &Y) {
394  return X && *X == Y;
395}
396 
397template <typename T>
398constexpr bool operator==(const T &X, const Optional<T> &Y) {
399  return Y && X == *Y;
400}
401 
402template <typename T>
403constexpr bool operator!=(const Optional<T> &X, const T &Y) {
404  return !(X == Y);
405}
406 
407template <typename T>
408constexpr bool operator!=(const T &X, const Optional<T> &Y) {
409  return !(X == Y);
410}
411 
412template <typename T>
413constexpr bool operator<(const Optional<T> &X, const T &Y) {
414  return !X || *X < Y;
415}
416 
417template <typename T>
418constexpr bool operator<(const T &X, const Optional<T> &Y) {
419  return Y && X < *Y;
420}
421 
422template <typename T>
423constexpr bool operator<=(const Optional<T> &X, const T &Y) {
424  return !(Y < X);
425}
426 
427template <typename T>
428constexpr bool operator<=(const T &X, const Optional<T> &Y) {
429  return !(Y < X);
430}
431 
432template <typename T>
433constexpr bool operator>(const Optional<T> &X, const T &Y) {
434  return Y < X;
435}
436 
437template <typename T>
438constexpr bool operator>(const T &X, const Optional<T> &Y) {
439  return Y < X;
440}
441 
442template <typename T>
443constexpr bool operator>=(const Optional<T> &X, const T &Y) {
444  return !(X < Y);
445}
446 
447template <typename T>
448constexpr bool operator>=(const T &X, const Optional<T> &Y) {
449  return !(X < Y);
450}
451 
452raw_ostream &operator<<(raw_ostream &OS, NoneType);
453 
454template <typename T, typename = decltype(std::declval<raw_ostream &>()
455                                          << std::declval<const T &>())>
456raw_ostream &operator<<(raw_ostream &OS, const Optional<T> &O) {
457  if (O)
458    OS << *O;
459  else
460    OS << None;
461  return OS;
462}
463 
464} // end namespace llvm
465 
466#endif // LLVM_ADT_OPTIONAL_H