/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp

Bug Summary

File:	lib/Analysis/InstructionSimplify.cpp
Warning:	line 1197, column 35 Called C++ object pointer is null
Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name InstructionSimplify.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-eagerly-assume -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 -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-7/lib/clang/7.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-7~svn329677/build-llvm/lib/Analysis -I /build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis -I /build/llvm-toolchain-snapshot-7~svn329677/build-llvm/include -I /build/llvm-toolchain-snapshot-7~svn329677/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0/backward -internal-isystem /usr/include/clang/7.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-7/lib/clang/7.0.0/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++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-7~svn329677/build-llvm/lib/Analysis -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-04-11-031539-24776-1 -x c++ /build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp
1//===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements routines for folding instructions into simpler forms
11// that do not require creating new instructions.  This does constant folding
12// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
13// returning a constant ("and i32 %x, 0" -> "0") or an already existing value
14// ("and i32 %x, %x" -> "%x").  All operands are assumed to have already been
15// simplified: This is usually true and assuming it simplifies the logic (if
16// they have not been simplified then results are correct but maybe suboptimal).
17//
18//===----------------------------------------------------------------------===//

20#include "llvm/Analysis/InstructionSimplify.h"
21#include "llvm/ADT/SetVector.h"
22#include "llvm/ADT/Statistic.h"
23#include "llvm/Analysis/AliasAnalysis.h"
24#include "llvm/Analysis/AssumptionCache.h"
25#include "llvm/Analysis/CaptureTracking.h"
26#include "llvm/Analysis/CmpInstAnalysis.h"
27#include "llvm/Analysis/ConstantFolding.h"
28#include "llvm/Analysis/LoopAnalysisManager.h"
29#include "llvm/Analysis/MemoryBuiltins.h"
30#include "llvm/Analysis/ValueTracking.h"
31#include "llvm/Analysis/VectorUtils.h"
32#include "llvm/IR/ConstantRange.h"
33#include "llvm/IR/DataLayout.h"
34#include "llvm/IR/Dominators.h"
35#include "llvm/IR/GetElementPtrTypeIterator.h"
36#include "llvm/IR/GlobalAlias.h"
37#include "llvm/IR/Operator.h"
38#include "llvm/IR/PatternMatch.h"
39#include "llvm/IR/ValueHandle.h"
40#include "llvm/Support/KnownBits.h"
41#include <algorithm>
42using namespace llvm;
43using namespace llvm::PatternMatch;

45#define DEBUG_TYPE"instsimplify" "instsimplify"

47enum { RecursionLimit = 3 };

49STATISTIC(NumExpand,  "Number of expansions")static llvm::Statistic NumExpand = {"instsimplify", "NumExpand"
, "Number of expansions", {0}, {false}};
50STATISTIC(NumReassoc, "Number of reassociations")static llvm::Statistic NumReassoc = {"instsimplify", "NumReassoc"
, "Number of reassociations", {0}, {false}};

52static Value *SimplifyAndInst(Value *, Value *, const SimplifyQuery &, unsigned);
53static Value *SimplifyBinOp(unsigned, Value *, Value *, const SimplifyQuery &,
                          unsigned);
55static Value *SimplifyFPBinOp(unsigned, Value *, Value *, const FastMathFlags &,
                            const SimplifyQuery &, unsigned);
57static Value *SimplifyCmpInst(unsigned, Value *, Value *, const SimplifyQuery &,
                            unsigned);
59static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
                             const SimplifyQuery &Q, unsigned MaxRecurse);
61static Value *SimplifyOrInst(Value *, Value *, const SimplifyQuery &, unsigned);
62static Value *SimplifyXorInst(Value *, Value *, const SimplifyQuery &, unsigned);
63static Value *SimplifyCastInst(unsigned, Value *, Type *,
                             const SimplifyQuery &, unsigned);

66/// For a boolean type or a vector of boolean type, return false or a vector
67/// with every element false.
68static Constant *getFalse(Type *Ty) {
return ConstantInt::getFalse(Ty);
70}

72/// For a boolean type or a vector of boolean type, return true or a vector
73/// with every element true.
74static Constant *getTrue(Type *Ty) {
return ConstantInt::getTrue(Ty);
76}

78/// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
79static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
                        Value *RHS) {
CmpInst *Cmp = dyn_cast<CmpInst>(V);
if (!Cmp)
  return false;
CmpInst::Predicate CPred = Cmp->getPredicate();
Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
if (CPred == Pred && CLHS == LHS && CRHS == RHS)
  return true;
return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
  CRHS == LHS;
90}

92/// Does the given value dominate the specified phi node?
93static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
Instruction *I = dyn_cast<Instruction>(V);
if (!I)
  // Arguments and constants dominate all instructions.
  return true;

// If we are processing instructions (and/or basic blocks) that have not been
// fully added to a function, the parent nodes may still be null. Simply
// return the conservative answer in these cases.
if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
  return false;

// If we have a DominatorTree then do a precise test.
if (DT)
  return DT->dominates(I, P);

// Otherwise, if the instruction is in the entry block and is not an invoke,
// then it obviously dominates all phi nodes.
if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
    !isa<InvokeInst>(I))
  return true;

return false;
116}

118/// Simplify "A op (B op' C)" by distributing op over op', turning it into
119/// "(A op B) op' (A op C)".  Here "op" is given by Opcode and "op'" is
120/// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
121/// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
122/// Returns the simplified value, or null if no simplification was performed.
123static Value *ExpandBinOp(Instruction::BinaryOps Opcode, Value *LHS, Value *RHS,
                        Instruction::BinaryOps OpcodeToExpand,
                        const SimplifyQuery &Q, unsigned MaxRecurse) {
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
  return nullptr;

// Check whether the expression has the form "(A op' B) op C".
if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
  if (Op0->getOpcode() == OpcodeToExpand) {
    // It does!  Try turning it into "(A op C) op' (B op C)".
    Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
    // Do "A op C" and "B op C" both simplify?
    if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
      if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
        // They do! Return "L op' R" if it simplifies or is already available.
        // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
        if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
                                   && L == B && R == A)) {
          ++NumExpand;
          return LHS;
        }
        // Otherwise return "L op' R" if it simplifies.
        if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
          ++NumExpand;
          return V;
        }
      }
  }

// Check whether the expression has the form "A op (B op' C)".
if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
  if (Op1->getOpcode() == OpcodeToExpand) {
    // It does!  Try turning it into "(A op B) op' (A op C)".
    Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
    // Do "A op B" and "A op C" both simplify?
    if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
      if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
        // They do! Return "L op' R" if it simplifies or is already available.
        // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
        if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
                                   && L == C && R == B)) {
          ++NumExpand;
          return RHS;
        }
        // Otherwise return "L op' R" if it simplifies.
        if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
          ++NumExpand;
          return V;
        }
      }
  }

return nullptr;
177}

179/// Generic simplifications for associative binary operations.
180/// Returns the simpler value, or null if none was found.
181static Value *SimplifyAssociativeBinOp(Instruction::BinaryOps Opcode,
                                     Value *LHS, Value *RHS,
                                     const SimplifyQuery &Q,
                                     unsigned MaxRecurse) {
assert(Instruction::isAssociative(Opcode) && "Not an associative operation!")(static_cast <bool> (Instruction::isAssociative(Opcode)
 && "Not an associative operation!") ? void (0) : __assert_fail
 ("Instruction::isAssociative(Opcode) && \"Not an associative operation!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 185, __extension__ __PRETTY_FUNCTION__));

// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
  return nullptr;

BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);

// Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
if (Op0 && Op0->getOpcode() == Opcode) {
  Value *A = Op0->getOperand(0);
  Value *B = Op0->getOperand(1);
  Value *C = RHS;

  // Does "B op C" simplify?
  if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
    // It does!  Return "A op V" if it simplifies or is already available.
    // If V equals B then "A op V" is just the LHS.
    if (V == B) return LHS;
    // Otherwise return "A op V" if it simplifies.
    if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
      ++NumReassoc;
      return W;
    }
  }
}

// Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
if (Op1 && Op1->getOpcode() == Opcode) {
  Value *A = LHS;
  Value *B = Op1->getOperand(0);
  Value *C = Op1->getOperand(1);

  // Does "A op B" simplify?
  if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
    // It does!  Return "V op C" if it simplifies or is already available.
    // If V equals B then "V op C" is just the RHS.
    if (V == B) return RHS;
    // Otherwise return "V op C" if it simplifies.
    if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
      ++NumReassoc;
      return W;
    }
  }
}

// The remaining transforms require commutativity as well as associativity.
if (!Instruction::isCommutative(Opcode))
  return nullptr;

// Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
if (Op0 && Op0->getOpcode() == Opcode) {
  Value *A = Op0->getOperand(0);
  Value *B = Op0->getOperand(1);
  Value *C = RHS;

  // Does "C op A" simplify?
  if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
    // It does!  Return "V op B" if it simplifies or is already available.
    // If V equals A then "V op B" is just the LHS.
    if (V == A) return LHS;
    // Otherwise return "V op B" if it simplifies.
    if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
      ++NumReassoc;
      return W;
    }
  }
}

// Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
if (Op1 && Op1->getOpcode() == Opcode) {
  Value *A = LHS;
  Value *B = Op1->getOperand(0);
  Value *C = Op1->getOperand(1);

  // Does "C op A" simplify?
  if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
    // It does!  Return "B op V" if it simplifies or is already available.
    // If V equals C then "B op V" is just the RHS.
    if (V == C) return RHS;
    // Otherwise return "B op V" if it simplifies.
    if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
      ++NumReassoc;
      return W;
    }
  }
}

return nullptr;
275}

277/// In the case of a binary operation with a select instruction as an operand,
278/// try to simplify the binop by seeing whether evaluating it on both branches
279/// of the select results in the same value. Returns the common value if so,
280/// otherwise returns null.
281static Value *ThreadBinOpOverSelect(Instruction::BinaryOps Opcode, Value *LHS,
                                  Value *RHS, const SimplifyQuery &Q,
                                  unsigned MaxRecurse) {
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
  return nullptr;

SelectInst *SI;
if (isa<SelectInst>(LHS)) {
  SI = cast<SelectInst>(LHS);
} else {
  assert(isa<SelectInst>(RHS) && "No select instruction operand!")(static_cast <bool> (isa<SelectInst>(RHS) &&
 "No select instruction operand!") ? void (0) : __assert_fail
 ("isa<SelectInst>(RHS) && \"No select instruction operand!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 292, __extension__ __PRETTY_FUNCTION__));
  SI = cast<SelectInst>(RHS);
}

// Evaluate the BinOp on the true and false branches of the select.
Value *TV;
Value *FV;
if (SI == LHS) {
  TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
  FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
} else {
  TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
  FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
}

// If they simplified to the same value, then return the common value.
// If they both failed to simplify then return null.
if (TV == FV)
  return TV;

// If one branch simplified to undef, return the other one.
if (TV && isa<UndefValue>(TV))
  return FV;
if (FV && isa<UndefValue>(FV))
  return TV;

// If applying the operation did not change the true and false select values,
// then the result of the binop is the select itself.
if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
  return SI;

// If one branch simplified and the other did not, and the simplified
// value is equal to the unsimplified one, return the simplified value.
// For example, select (cond, X, X & Z) & Z -> X & Z.
if ((FV && !TV) || (TV && !FV)) {
  // Check that the simplified value has the form "X op Y" where "op" is the
  // same as the original operation.
  Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
  if (Simplified && Simplified->getOpcode() == unsigned(Opcode)) {
    // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
    // We already know that "op" is the same as for the simplified value.  See
    // if the operands match too.  If so, return the simplified value.
    Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
    Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
    Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
    if (Simplified->getOperand(0) == UnsimplifiedLHS &&
        Simplified->getOperand(1) == UnsimplifiedRHS)
      return Simplified;
    if (Simplified->isCommutative() &&
        Simplified->getOperand(1) == UnsimplifiedLHS &&
        Simplified->getOperand(0) == UnsimplifiedRHS)
      return Simplified;
  }
}

return nullptr;
348}

350/// In the case of a comparison with a select instruction, try to simplify the
351/// comparison by seeing whether both branches of the select result in the same
352/// value. Returns the common value if so, otherwise returns null.
353static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
                                Value *RHS, const SimplifyQuery &Q,
                                unsigned MaxRecurse) {
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
  return nullptr;

// Make sure the select is on the LHS.
if (!isa<SelectInst>(LHS)) {
  std::swap(LHS, RHS);
  Pred = CmpInst::getSwappedPredicate(Pred);
}
assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!")(static_cast <bool> (isa<SelectInst>(LHS) &&
 "Not comparing with a select instruction!") ? void (0) : __assert_fail
 ("isa<SelectInst>(LHS) && \"Not comparing with a select instruction!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 365, __extension__ __PRETTY_FUNCTION__));
SelectInst *SI = cast<SelectInst>(LHS);
Value *Cond = SI->getCondition();
Value *TV = SI->getTrueValue();
Value *FV = SI->getFalseValue();

// Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
// Does "cmp TV, RHS" simplify?
Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
if (TCmp == Cond) {
  // It not only simplified, it simplified to the select condition.  Replace
  // it with 'true'.
  TCmp = getTrue(Cond->getType());
} else if (!TCmp) {
  // It didn't simplify.  However if "cmp TV, RHS" is equal to the select
  // condition then we can replace it with 'true'.  Otherwise give up.
  if (!isSameCompare(Cond, Pred, TV, RHS))
    return nullptr;
  TCmp = getTrue(Cond->getType());
}

// Does "cmp FV, RHS" simplify?
Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
if (FCmp == Cond) {
  // It not only simplified, it simplified to the select condition.  Replace
  // it with 'false'.
  FCmp = getFalse(Cond->getType());
} else if (!FCmp) {
  // It didn't simplify.  However if "cmp FV, RHS" is equal to the select
  // condition then we can replace it with 'false'.  Otherwise give up.
  if (!isSameCompare(Cond, Pred, FV, RHS))
    return nullptr;
  FCmp = getFalse(Cond->getType());
}

// If both sides simplified to the same value, then use it as the result of
// the original comparison.
if (TCmp == FCmp)
  return TCmp;

// The remaining cases only make sense if the select condition has the same
// type as the result of the comparison, so bail out if this is not so.
if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
  return nullptr;
// If the false value simplified to false, then the result of the compare
// is equal to "Cond && TCmp".  This also catches the case when the false
// value simplified to false and the true value to true, returning "Cond".
if (match(FCmp, m_Zero()))
  if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
    return V;
// If the true value simplified to true, then the result of the compare
// is equal to "Cond || FCmp".
if (match(TCmp, m_One()))
  if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
    return V;
// Finally, if the false value simplified to true and the true value to
// false, then the result of the compare is equal to "!Cond".
if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
  if (Value *V =
      SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
                      Q, MaxRecurse))
    return V;

return nullptr;
429}

431/// In the case of a binary operation with an operand that is a PHI instruction,
432/// try to simplify the binop by seeing whether evaluating it on the incoming
433/// phi values yields the same result for every value. If so returns the common
434/// value, otherwise returns null.
435static Value *ThreadBinOpOverPHI(Instruction::BinaryOps Opcode, Value *LHS,
                               Value *RHS, const SimplifyQuery &Q,
                               unsigned MaxRecurse) {
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
  return nullptr;

PHINode *PI;
if (isa<PHINode>(LHS)) {
  PI = cast<PHINode>(LHS);
  // Bail out if RHS and the phi may be mutually interdependent due to a loop.
  if (!ValueDominatesPHI(RHS, PI, Q.DT))
    return nullptr;
} else {
  assert(isa<PHINode>(RHS) && "No PHI instruction operand!")(static_cast <bool> (isa<PHINode>(RHS) &&
 "No PHI instruction operand!") ? void (0) : __assert_fail ("isa<PHINode>(RHS) && \"No PHI instruction operand!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 449, __extension__ __PRETTY_FUNCTION__));
  PI = cast<PHINode>(RHS);
  // Bail out if LHS and the phi may be mutually interdependent due to a loop.
  if (!ValueDominatesPHI(LHS, PI, Q.DT))
    return nullptr;
}

// Evaluate the BinOp on the incoming phi values.
Value *CommonValue = nullptr;
for (Value *Incoming : PI->incoming_values()) {
  // If the incoming value is the phi node itself, it can safely be skipped.
  if (Incoming == PI) continue;
  Value *V = PI == LHS ?
    SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
    SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
  // If the operation failed to simplify, or simplified to a different value
  // to previously, then give up.
  if (!V || (CommonValue && V != CommonValue))
    return nullptr;
  CommonValue = V;
}

return CommonValue;
472}

474/// In the case of a comparison with a PHI instruction, try to simplify the
475/// comparison by seeing whether comparing with all of the incoming phi values
476/// yields the same result every time. If so returns the common result,
477/// otherwise returns null.
478static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
                             const SimplifyQuery &Q, unsigned MaxRecurse) {
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
  return nullptr;

// Make sure the phi is on the LHS.
if (!isa<PHINode>(LHS)) {
  std::swap(LHS, RHS);
  Pred = CmpInst::getSwappedPredicate(Pred);
}
assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!")(static_cast <bool> (isa<PHINode>(LHS) &&
 "Not comparing with a phi instruction!") ? void (0) : __assert_fail
 ("isa<PHINode>(LHS) && \"Not comparing with a phi instruction!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 489, __extension__ __PRETTY_FUNCTION__));
PHINode *PI = cast<PHINode>(LHS);

// Bail out if RHS and the phi may be mutually interdependent due to a loop.
if (!ValueDominatesPHI(RHS, PI, Q.DT))
  return nullptr;

// Evaluate the BinOp on the incoming phi values.
Value *CommonValue = nullptr;
for (Value *Incoming : PI->incoming_values()) {
  // If the incoming value is the phi node itself, it can safely be skipped.
  if (Incoming == PI) continue;
  Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
  // If the operation failed to simplify, or simplified to a different value
  // to previously, then give up.
  if (!V || (CommonValue && V != CommonValue))
    return nullptr;
  CommonValue = V;
}

return CommonValue;
510}

512static Constant *foldOrCommuteConstant(Instruction::BinaryOps Opcode,
                                     Value *&Op0, Value *&Op1,
                                     const SimplifyQuery &Q) {
if (auto *CLHS = dyn_cast<Constant>(Op0)) {
  if (auto *CRHS = dyn_cast<Constant>(Op1))
    return ConstantFoldBinaryOpOperands(Opcode, CLHS, CRHS, Q.DL);

  // Canonicalize the constant to the RHS if this is a commutative operation.
  if (Instruction::isCommutative(Opcode))
    std::swap(Op0, Op1);
}
return nullptr;
524}

526/// Given operands for an Add, see if we can fold the result.
527/// If not, this returns null.
528static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
                            const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Instruction::Add, Op0, Op1, Q))
  return C;

// X + undef -> undef
if (match(Op1, m_Undef()))
  return Op1;

// X + 0 -> X
if (match(Op1, m_Zero()))
  return Op0;

// X + (Y - X) -> Y
// (Y - X) + X -> Y
// Eg: X + -X -> 0
Value *Y = nullptr;
if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
    match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
  return Y;

// X + ~X -> -1   since   ~X = -X-1
Type *Ty = Op0->getType();
if (match(Op0, m_Not(m_Specific(Op1))) ||
    match(Op1, m_Not(m_Specific(Op0))))
  return Constant::getAllOnesValue(Ty);

// add nsw/nuw (xor Y, signmask), signmask --> Y
// The no-wrapping add guarantees that the top bit will be set by the add.
// Therefore, the xor must be clearing the already set sign bit of Y.
if ((isNSW || isNUW) && match(Op1, m_SignMask()) &&
    match(Op0, m_Xor(m_Value(Y), m_SignMask())))
  return Y;

/// i1 add -> xor.
if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
  if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
    return V;

// Try some generic simplifications for associative operations.
if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
                                        MaxRecurse))
  return V;

// Threading Add over selects and phi nodes is pointless, so don't bother.
// Threading over the select in "A + select(cond, B, C)" means evaluating
// "A+B" and "A+C" and seeing if they are equal; but they are equal if and
// only if B and C are equal.  If B and C are equal then (since we assume
// that operands have already been simplified) "select(cond, B, C)" should
// have been simplified to the common value of B and C already.  Analysing
// "A+B" and "A+C" thus gains nothing, but costs compile time.  Similarly
// for threading over phi nodes.

return nullptr;
582}

584Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
                           const SimplifyQuery &Query) {
return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query, RecursionLimit);
587}

589/// \brief Compute the base pointer and cumulative constant offsets for V.
590///
591/// This strips all constant offsets off of V, leaving it the base pointer, and
592/// accumulates the total constant offset applied in the returned constant. It
593/// returns 0 if V is not a pointer, and returns the constant '0' if there are
594/// no constant offsets applied.
595///
596/// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
597/// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
598/// folding.
599static Constant *stripAndComputeConstantOffsets(const DataLayout &DL, Value *&V,
                                              bool AllowNonInbounds = false) {
assert(V->getType()->isPtrOrPtrVectorTy())(static_cast <bool> (V->getType()->isPtrOrPtrVectorTy
()) ? void (0) : __assert_fail ("V->getType()->isPtrOrPtrVectorTy()"
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 601, __extension__ __PRETTY_FUNCTION__));

Type *IntPtrTy = DL.getIntPtrType(V->getType())->getScalarType();
APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());

// Even though we don't look through PHI nodes, we could be called on an
// instruction in an unreachable block, which may be on a cycle.
SmallPtrSet<Value *, 4> Visited;
Visited.insert(V);
do {
  if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
    if ((!AllowNonInbounds && !GEP->isInBounds()) ||
        !GEP->accumulateConstantOffset(DL, Offset))
      break;
    V = GEP->getPointerOperand();
  } else if (Operator::getOpcode(V) == Instruction::BitCast) {
    V = cast<Operator>(V)->getOperand(0);
  } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
    if (GA->isInterposable())
      break;
    V = GA->getAliasee();
  } else {
    if (auto CS = CallSite(V))
      if (Value *RV = CS.getReturnedArgOperand()) {
        V = RV;
        continue;
      }
    break;
  }
  assert(V->getType()->isPtrOrPtrVectorTy() && "Unexpected operand type!")(static_cast <bool> (V->getType()->isPtrOrPtrVectorTy
() && "Unexpected operand type!") ? void (0) : __assert_fail
 ("V->getType()->isPtrOrPtrVectorTy() && \"Unexpected operand type!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 630, __extension__ __PRETTY_FUNCTION__));
} while (Visited.insert(V).second);

Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
if (V->getType()->isVectorTy())
  return ConstantVector::getSplat(V->getType()->getVectorNumElements(),
                                  OffsetIntPtr);
return OffsetIntPtr;
638}

640/// \brief Compute the constant difference between two pointer values.
641/// If the difference is not a constant, returns zero.
642static Constant *computePointerDifference(const DataLayout &DL, Value *LHS,
                                        Value *RHS) {
Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);

// If LHS and RHS are not related via constant offsets to the same base
// value, there is nothing we can do here.
if (LHS != RHS)
  return nullptr;

// Otherwise, the difference of LHS - RHS can be computed as:
//    LHS - RHS
//  = (LHSOffset + Base) - (RHSOffset + Base)
//  = LHSOffset - RHSOffset
return ConstantExpr::getSub(LHSOffset, RHSOffset);
657}

659/// Given operands for a Sub, see if we can fold the result.
660/// If not, this returns null.
661static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
                            const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Instruction::Sub, Op0, Op1, Q))
  return C;

// X - undef -> undef
// undef - X -> undef
if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
  return UndefValue::get(Op0->getType());

// X - 0 -> X
if (match(Op1, m_Zero()))
  return Op0;

// X - X -> 0
if (Op0 == Op1)
  return Constant::getNullValue(Op0->getType());

// Is this a negation?
if (match(Op0, m_Zero())) {
  // 0 - X -> 0 if the sub is NUW.
  if (isNUW)
    return Op0;

  KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
  if (Known.Zero.isMaxSignedValue()) {
    // Op1 is either 0 or the minimum signed value. If the sub is NSW, then
    // Op1 must be 0 because negating the minimum signed value is undefined.
    if (isNSW)
      return Op0;

    // 0 - X -> X if X is 0 or the minimum signed value.
    return Op1;
  }
}

// (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
// For example, (X + Y) - Y -> X; (Y + X) - Y -> X
Value *X = nullptr, *Y = nullptr, *Z = Op1;
if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
  // See if "V === Y - Z" simplifies.
  if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
    // It does!  Now see if "X + V" simplifies.
    if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
      // It does, we successfully reassociated!
      ++NumReassoc;
      return W;
    }
  // See if "V === X - Z" simplifies.
  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
    // It does!  Now see if "Y + V" simplifies.
    if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
      // It does, we successfully reassociated!
      ++NumReassoc;
      return W;
    }
}

// X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
// For example, X - (X + 1) -> -1
X = Op0;
if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
  // See if "V === X - Y" simplifies.
  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
    // It does!  Now see if "V - Z" simplifies.
    if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
      // It does, we successfully reassociated!
      ++NumReassoc;
      return W;
    }
  // See if "V === X - Z" simplifies.
  if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
    // It does!  Now see if "V - Y" simplifies.
    if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
      // It does, we successfully reassociated!
      ++NumReassoc;
      return W;
    }
}

// Z - (X - Y) -> (Z - X) + Y if everything simplifies.
// For example, X - (X - Y) -> Y.
Z = Op0;
if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
  // See if "V === Z - X" simplifies.
  if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
    // It does!  Now see if "V + Y" simplifies.
    if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
      // It does, we successfully reassociated!
      ++NumReassoc;
      return W;
    }

// trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
    match(Op1, m_Trunc(m_Value(Y))))
  if (X->getType() == Y->getType())
    // See if "V === X - Y" simplifies.
    if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
      // It does!  Now see if "trunc V" simplifies.
      if (Value *W = SimplifyCastInst(Instruction::Trunc, V, Op0->getType(),
                                      Q, MaxRecurse - 1))
        // It does, return the simplified "trunc V".
        return W;

// Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
if (match(Op0, m_PtrToInt(m_Value(X))) &&
    match(Op1, m_PtrToInt(m_Value(Y))))
  if (Constant *Result = computePointerDifference(Q.DL, X, Y))
    return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);

// i1 sub -> xor.
if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
  if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
    return V;

// Threading Sub over selects and phi nodes is pointless, so don't bother.
// Threading over the select in "A - select(cond, B, C)" means evaluating
// "A-B" and "A-C" and seeing if they are equal; but they are equal if and
// only if B and C are equal.  If B and C are equal then (since we assume
// that operands have already been simplified) "select(cond, B, C)" should
// have been simplified to the common value of B and C already.  Analysing
// "A-B" and "A-C" thus gains nothing, but costs compile time.  Similarly
// for threading over phi nodes.

return nullptr;
787}

789Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
                           const SimplifyQuery &Q) {
return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
792}

794/// Given operands for a Mul, see if we can fold the result.
795/// If not, this returns null.
796static Value *SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                            unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Instruction::Mul, Op0, Op1, Q))
  return C;

// X * undef -> 0
if (match(Op1, m_Undef()))
  return Constant::getNullValue(Op0->getType());

// X * 0 -> 0
if (match(Op1, m_Zero()))
  return Op1;

// X * 1 -> X
if (match(Op1, m_One()))
  return Op0;

// (X / Y) * Y -> X if the division is exact.
Value *X = nullptr;
if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
    match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0)))))   // Y * (X / Y)
  return X;

// i1 mul -> and.
if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
  if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
    return V;

// Try some generic simplifications for associative operations.
if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
                                        MaxRecurse))
  return V;

// Mul distributes over Add. Try some generic simplifications based on this.
if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
                           Q, MaxRecurse))
  return V;

// If the operation is with the result of a select instruction, check whether
// operating on either branch of the select always yields the same value.
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
  if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
                                       MaxRecurse))
    return V;

// If the operation is with the result of a phi instruction, check whether
// operating on all incoming values of the phi always yields the same value.
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
  if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
                                    MaxRecurse))
    return V;

return nullptr;
849}

851Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
return ::SimplifyMulInst(Op0, Op1, Q, RecursionLimit);
853}

855/// Check for common or similar folds of integer division or integer remainder.
856/// This applies to all 4 opcodes (sdiv/udiv/srem/urem).
857static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) {
Type *Ty = Op0->getType();

// X / undef -> undef
// X % undef -> undef
if (match(Op1, m_Undef()))
  return Op1;

// X / 0 -> undef
// X % 0 -> undef
// We don't need to preserve faults!
if (match(Op1, m_Zero()))
  return UndefValue::get(Ty);

// If any element of a constant divisor vector is zero or undef, the whole op
// is undef.
auto *Op1C = dyn_cast<Constant>(Op1);
if (Op1C && Ty->isVectorTy()) {
  unsigned NumElts = Ty->getVectorNumElements();
  for (unsigned i = 0; i != NumElts; ++i) {
    Constant *Elt = Op1C->getAggregateElement(i);
    if (Elt && (Elt->isNullValue() || isa<UndefValue>(Elt)))
      return UndefValue::get(Ty);
  }
}

// undef / X -> 0
// undef % X -> 0
if (match(Op0, m_Undef()))
  return Constant::getNullValue(Ty);

// 0 / X -> 0
// 0 % X -> 0
if (match(Op0, m_Zero()))
  return Op0;

// X / X -> 1
// X % X -> 0
if (Op0 == Op1)
  return IsDiv ? ConstantInt::get(Ty, 1) : Constant::getNullValue(Ty);

// X / 1 -> X
// X % 1 -> 0
// If this is a boolean op (single-bit element type), we can't have
// division-by-zero or remainder-by-zero, so assume the divisor is 1.
if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1))
  return IsDiv ? Op0 : Constant::getNullValue(Ty);

return nullptr;
906}

908/// Given a predicate and two operands, return true if the comparison is true.
909/// This is a helper for div/rem simplification where we return some other value
910/// when we can prove a relationship between the operands.
911static bool isICmpTrue(ICmpInst::Predicate Pred, Value *LHS, Value *RHS,
                     const SimplifyQuery &Q, unsigned MaxRecurse) {
Value *V = SimplifyICmpInst(Pred, LHS, RHS, Q, MaxRecurse);
Constant *C = dyn_cast_or_null<Constant>(V);
return (C && C->isAllOnesValue());
916}

918/// Return true if we can simplify X / Y to 0. Remainder can adapt that answer
919/// to simplify X % Y to X.
920static bool isDivZero(Value *X, Value *Y, const SimplifyQuery &Q,
                    unsigned MaxRecurse, bool IsSigned) {
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
  return false;

if (IsSigned) {
  // |X| / |Y| --> 0
  //
  // We require that 1 operand is a simple constant. That could be extended to
  // 2 variables if we computed the sign bit for each.
  //
  // Make sure that a constant is not the minimum signed value because taking
  // the abs() of that is undefined.
  Type *Ty = X->getType();
  const APInt *C;
  if (match(X, m_APInt(C)) && !C->isMinSignedValue()) {
    // Is the variable divisor magnitude always greater than the constant
    // dividend magnitude?
    // |Y| > |C| --> Y < -abs(C) or Y > abs(C)
    Constant *PosDividendC = ConstantInt::get(Ty, C->abs());
    Constant *NegDividendC = ConstantInt::get(Ty, -C->abs());
    if (isICmpTrue(CmpInst::ICMP_SLT, Y, NegDividendC, Q, MaxRecurse) ||
        isICmpTrue(CmpInst::ICMP_SGT, Y, PosDividendC, Q, MaxRecurse))
      return true;
  }
  if (match(Y, m_APInt(C))) {
    // Special-case: we can't take the abs() of a minimum signed value. If
    // that's the divisor, then all we have to do is prove that the dividend
    // is also not the minimum signed value.
    if (C->isMinSignedValue())
      return isICmpTrue(CmpInst::ICMP_NE, X, Y, Q, MaxRecurse);

    // Is the variable dividend magnitude always less than the constant
    // divisor magnitude?
    // |X| < |C| --> X > -abs(C) and X < abs(C)
    Constant *PosDivisorC = ConstantInt::get(Ty, C->abs());
    Constant *NegDivisorC = ConstantInt::get(Ty, -C->abs());
    if (isICmpTrue(CmpInst::ICMP_SGT, X, NegDivisorC, Q, MaxRecurse) &&
        isICmpTrue(CmpInst::ICMP_SLT, X, PosDivisorC, Q, MaxRecurse))
      return true;
  }
  return false;
}

// IsSigned == false.
// Is the dividend unsigned less than the divisor?
return isICmpTrue(ICmpInst::ICMP_ULT, X, Y, Q, MaxRecurse);
968}

970/// These are simplifications common to SDiv and UDiv.
971static Value *simplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
                        const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
  return C;

if (Value *V = simplifyDivRem(Op0, Op1, true))
  return V;

bool IsSigned = Opcode == Instruction::SDiv;

// (X * Y) / Y -> X if the multiplication does not overflow.
Value *X;
if (match(Op0, m_c_Mul(m_Value(X), m_Specific(Op1)))) {
  auto *Mul = cast<OverflowingBinaryOperator>(Op0);
  // If the Mul does not overflow, then we are good to go.
  if ((IsSigned && Mul->hasNoSignedWrap()) ||
      (!IsSigned && Mul->hasNoUnsignedWrap()))
    return X;
  // If X has the form X = A / Y, then X * Y cannot overflow.
  if ((IsSigned && match(X, m_SDiv(m_Value(), m_Specific(Op1)))) ||
      (!IsSigned && match(X, m_UDiv(m_Value(), m_Specific(Op1)))))
    return X;
}

// (X rem Y) / Y -> 0
if ((IsSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
    (!IsSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
  return Constant::getNullValue(Op0->getType());

// (X /u C1) /u C2 -> 0 if C1 * C2 overflow
ConstantInt *C1, *C2;
if (!IsSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) &&
    match(Op1, m_ConstantInt(C2))) {
  bool Overflow;
  (void)C1->getValue().umul_ov(C2->getValue(), Overflow);
  if (Overflow)
    return Constant::getNullValue(Op0->getType());
}

// If the operation is with the result of a select instruction, check whether
// operating on either branch of the select always yields the same value.
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
    return V;

// If the operation is with the result of a phi instruction, check whether
// operating on all incoming values of the phi always yields the same value.
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
    return V;

if (isDivZero(Op0, Op1, Q, MaxRecurse, IsSigned))
  return Constant::getNullValue(Op0->getType());

return nullptr;
1026}

1028/// These are simplifications common to SRem and URem.
1029static Value *simplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
                        const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
  return C;

if (Value *V = simplifyDivRem(Op0, Op1, false))
  return V;

// (X % Y) % Y -> X % Y
if ((Opcode == Instruction::SRem &&
     match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
    (Opcode == Instruction::URem &&
     match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
  return Op0;

// (X << Y) % X -> 0
if ((Opcode == Instruction::SRem &&
     match(Op0, m_NSWShl(m_Specific(Op1), m_Value()))) ||
    (Opcode == Instruction::URem &&
     match(Op0, m_NUWShl(m_Specific(Op1), m_Value()))))
  return Constant::getNullValue(Op0->getType());

// If the operation is with the result of a select instruction, check whether
// operating on either branch of the select always yields the same value.
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
    return V;

// If the operation is with the result of a phi instruction, check whether
// operating on all incoming values of the phi always yields the same value.
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
    return V;

// If X / Y == 0, then X % Y == X.
if (isDivZero(Op0, Op1, Q, MaxRecurse, Opcode == Instruction::SRem))
  return Op0;

return nullptr;
1068}

1070/// Given operands for an SDiv, see if we can fold the result.
1071/// If not, this returns null.
1072static Value *SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                             unsigned MaxRecurse) {
return simplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse);
1075}

1077Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
return ::SimplifySDivInst(Op0, Op1, Q, RecursionLimit);
1079}

1081/// Given operands for a UDiv, see if we can fold the result.
1082/// If not, this returns null.
1083static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                             unsigned MaxRecurse) {
return simplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse);
1086}

1088Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
return ::SimplifyUDivInst(Op0, Op1, Q, RecursionLimit);
1090}

1092/// Given operands for an SRem, see if we can fold the result.
1093/// If not, this returns null.
1094static Value *SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                             unsigned MaxRecurse) {
return simplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse);
1097}

1099Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
return ::SimplifySRemInst(Op0, Op1, Q, RecursionLimit);
1101}

1103/// Given operands for a URem, see if we can fold the result.
1104/// If not, this returns null.
1105static Value *SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                             unsigned MaxRecurse) {
return simplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse);
1108}

1110Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
return ::SimplifyURemInst(Op0, Op1, Q, RecursionLimit);
1112}

1114/// Returns true if a shift by \c Amount always yields undef.
1115static bool isUndefShift(Value *Amount) {
Constant *C = dyn_cast<Constant>(Amount);
if (!C)
  return false;

// X shift by undef -> undef because it may shift by the bitwidth.
if (isa<UndefValue>(C))
  return true;

// Shifting by the bitwidth or more is undefined.
if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
  if (CI->getValue().getLimitedValue() >=
      CI->getType()->getScalarSizeInBits())
    return true;

// If all lanes of a vector shift are undefined the whole shift is.
if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
  for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
    if (!isUndefShift(C->getAggregateElement(I)))
      return false;
  return true;
}

return false;
1139}

1141/// Given operands for an Shl, LShr or AShr, see if we can fold the result.
1142/// If not, this returns null.
1143static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0,
                          Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q))
  return C;

// 0 shift by X -> 0
if (match(Op0, m_Zero()))
  return Op0;

// X shift by 0 -> X
if (match(Op1, m_Zero()))
  return Op0;

// Fold undefined shifts.
if (isUndefShift(Op1))
  return UndefValue::get(Op0->getType());

// If the operation is with the result of a select instruction, check whether
// operating on either branch of the select always yields the same value.
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
  if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
    return V;

// If the operation is with the result of a phi instruction, check whether
// operating on all incoming values of the phi always yields the same value.
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
  if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
    return V;

// If any bits in the shift amount make that value greater than or equal to
// the number of bits in the type, the shift is undefined.
KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
if (Known.One.getLimitedValue() >= Known.getBitWidth())
  return UndefValue::get(Op0->getType());

// If all valid bits in the shift amount are known zero, the first operand is
// unchanged.
unsigned NumValidShiftBits = Log2_32_Ceil(Known.getBitWidth());
if (Known.countMinTrailingZeros() >= NumValidShiftBits)
  return Op0;

return nullptr;
1185}

1187/// \brief Given operands for an Shl, LShr or AShr, see if we can
1188/// fold the result.  If not, this returns null.
1189static Value *SimplifyRightShift(Instruction::BinaryOps Opcode, Value *Op0,
                               Value *Op1, bool isExact, const SimplifyQuery &Q,
                               unsigned MaxRecurse) {
if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse))
6
←
Assuming 'V' is null→
7
←
Assuming pointer value is null→
8
←
Taking false branch→
  return V;

// X >> X -> 0
if (Op0 == Op1)
9
←
Assuming 'Op0' is equal to 'Op1'→
10
←
Taking true branch→
  return Constant::getNullValue(Op0->getType());
11
←
Called C++ object pointer is null

// undef >> X -> 0
// undef >> X -> undef (if it's exact)
if (match(Op0, m_Undef()))
  return isExact ? Op0 : Constant::getNullValue(Op0->getType());

// The low bit cannot be shifted out of an exact shift if it is set.
if (isExact) {
  KnownBits Op0Known = computeKnownBits(Op0, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
  if (Op0Known.One[0])
    return Op0;
}

return nullptr;
1212}

1214/// Given operands for an Shl, see if we can fold the result.
1215/// If not, this returns null.
1216static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
                            const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
  return V;

// undef << X -> 0
// undef << X -> undef if (if it's NSW/NUW)
if (match(Op0, m_Undef()))
  return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType());

// (X >> A) << A -> X
Value *X;
if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
  return X;
return nullptr;
1231}

1233Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
                           const SimplifyQuery &Q) {
return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit);
1236}

1238/// Given operands for an LShr, see if we can fold the result.
1239/// If not, this returns null.
1240static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
                             const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q,
                                  MaxRecurse))
    return V;

// (X << A) >> A -> X
Value *X;
if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
  return X;

return nullptr;
1252}

1254Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
                            const SimplifyQuery &Q) {
return ::SimplifyLShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1257}

1259/// Given operands for an AShr, see if we can fold the result.
1260/// If not, this returns null.
1261static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
                             const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q,
4
←
Passing value via 2nd parameter 'Op0'→
5
←
Calling 'SimplifyRightShift'→
                                  MaxRecurse))
  return V;

// all ones >>a X -> -1
// Do not return Op0 because it may contain undef elements if it's a vector.
if (match(Op0, m_AllOnes()))
  return Constant::getAllOnesValue(Op0->getType());

// (X << A) >> A -> X
Value *X;
if (match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1))))
  return X;

// Arithmetic shifting an all-sign-bit value is a no-op.
unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
if (NumSignBits == Op0->getType()->getScalarSizeInBits())
  return Op0;

return nullptr;
1283}

1285Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
                            const SimplifyQuery &Q) {
return ::SimplifyAShrInst(Op0, Op1, isExact, Q, RecursionLimit);
1288}

1290/// Commuted variants are assumed to be handled by calling this function again
1291/// with the parameters swapped.
1292static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp,
                                       ICmpInst *UnsignedICmp, bool IsAnd) {
Value *X, *Y;

ICmpInst::Predicate EqPred;
if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) ||
    !ICmpInst::isEquality(EqPred))
  return nullptr;

ICmpInst::Predicate UnsignedPred;
if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) &&
    ICmpInst::isUnsigned(UnsignedPred))
  ;
else if (match(UnsignedICmp,
               m_ICmp(UnsignedPred, m_Value(Y), m_Specific(X))) &&
         ICmpInst::isUnsigned(UnsignedPred))
  UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
else
  return nullptr;

// X < Y && Y != 0  -->  X < Y
// X < Y || Y != 0  -->  Y != 0
if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE)
  return IsAnd ? UnsignedICmp : ZeroICmp;

// X >= Y || Y != 0  -->  true
// X >= Y || Y == 0  -->  X >= Y
if (UnsignedPred == ICmpInst::ICMP_UGE && !IsAnd) {
  if (EqPred == ICmpInst::ICMP_NE)
    return getTrue(UnsignedICmp->getType());
  return UnsignedICmp;
}

// X < Y && Y == 0  -->  false
if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ &&
    IsAnd)
  return getFalse(UnsignedICmp->getType());

return nullptr;
1331}

1333/// Commuted variants are assumed to be handled by calling this function again
1334/// with the parameters swapped.
1335static Value *simplifyAndOfICmpsWithSameOperands(ICmpInst *Op0, ICmpInst *Op1) {
ICmpInst::Predicate Pred0, Pred1;
Value *A ,*B;
if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
    !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
  return nullptr;

// We have (icmp Pred0, A, B) & (icmp Pred1, A, B).
// If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
// can eliminate Op1 from this 'and'.
if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
  return Op0;

// Check for any combination of predicates that are guaranteed to be disjoint.
if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
    (Pred0 == ICmpInst::ICMP_EQ && ICmpInst::isFalseWhenEqual(Pred1)) ||
    (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT) ||
    (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT))
  return getFalse(Op0->getType());

return nullptr;
1356}

1358/// Commuted variants are assumed to be handled by calling this function again
1359/// with the parameters swapped.
1360static Value *simplifyOrOfICmpsWithSameOperands(ICmpInst *Op0, ICmpInst *Op1) {
ICmpInst::Predicate Pred0, Pred1;
Value *A ,*B;
if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
    !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
  return nullptr;

// We have (icmp Pred0, A, B) | (icmp Pred1, A, B).
// If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
// can eliminate Op0 from this 'or'.
if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1))
  return Op1;

// Check for any combination of predicates that cover the entire range of
// possibilities.
if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) ||
    (Pred0 == ICmpInst::ICMP_NE && ICmpInst::isTrueWhenEqual(Pred1)) ||
    (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGE) ||
    (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGE))
  return getTrue(Op0->getType());

return nullptr;
1382}

1384/// Test if a pair of compares with a shared operand and 2 constants has an
1385/// empty set intersection, full set union, or if one compare is a superset of
1386/// the other.
1387static Value *simplifyAndOrOfICmpsWithConstants(ICmpInst *Cmp0, ICmpInst *Cmp1,
                                              bool IsAnd) {
// Look for this pattern: {and/or} (icmp X, C0), (icmp X, C1)).
if (Cmp0->getOperand(0) != Cmp1->getOperand(0))
  return nullptr;

const APInt *C0, *C1;
if (!match(Cmp0->getOperand(1), m_APInt(C0)) ||
    !match(Cmp1->getOperand(1), m_APInt(C1)))
  return nullptr;

auto Range0 = ConstantRange::makeExactICmpRegion(Cmp0->getPredicate(), *C0);
auto Range1 = ConstantRange::makeExactICmpRegion(Cmp1->getPredicate(), *C1);

// For and-of-compares, check if the intersection is empty:
// (icmp X, C0) && (icmp X, C1) --> empty set --> false
if (IsAnd && Range0.intersectWith(Range1).isEmptySet())
  return getFalse(Cmp0->getType());

// For or-of-compares, check if the union is full:
// (icmp X, C0) || (icmp X, C1) --> full set --> true
if (!IsAnd && Range0.unionWith(Range1).isFullSet())
  return getTrue(Cmp0->getType());

// Is one range a superset of the other?
// If this is and-of-compares, take the smaller set:
// (icmp sgt X, 4) && (icmp sgt X, 42) --> icmp sgt X, 42
// If this is or-of-compares, take the larger set:
// (icmp sgt X, 4) || (icmp sgt X, 42) --> icmp sgt X, 4
if (Range0.contains(Range1))
  return IsAnd ? Cmp1 : Cmp0;
if (Range1.contains(Range0))
  return IsAnd ? Cmp0 : Cmp1;

return nullptr;
1422}

1424static Value *simplifyAndOrOfICmpsWithZero(ICmpInst *Cmp0, ICmpInst *Cmp1,
                                         bool IsAnd) {
ICmpInst::Predicate P0 = Cmp0->getPredicate(), P1 = Cmp1->getPredicate();
if (!match(Cmp0->getOperand(1), m_Zero()) ||
    !match(Cmp1->getOperand(1), m_Zero()) || P0 != P1)
  return nullptr;

if ((IsAnd && P0 != ICmpInst::ICMP_NE) || (!IsAnd && P1 != ICmpInst::ICMP_EQ))
  return nullptr;

// We have either "(X == 0 || Y == 0)" or "(X != 0 && Y != 0)".
Value *X = Cmp0->getOperand(0);
Value *Y = Cmp1->getOperand(0);

// If one of the compares is a masked version of a (not) null check, then
// that compare implies the other, so we eliminate the other. Optionally, look
// through a pointer-to-int cast to match a null check of a pointer type.

// (X == 0) || (([ptrtoint] X & ?) == 0) --> ([ptrtoint] X & ?) == 0
// (X == 0) || ((? & [ptrtoint] X) == 0) --> (? & [ptrtoint] X) == 0
// (X != 0) && (([ptrtoint] X & ?) != 0) --> ([ptrtoint] X & ?) != 0
// (X != 0) && ((? & [ptrtoint] X) != 0) --> (? & [ptrtoint] X) != 0
if (match(Y, m_c_And(m_Specific(X), m_Value())) ||
    match(Y, m_c_And(m_PtrToInt(m_Specific(X)), m_Value())))
  return Cmp1;

// (([ptrtoint] Y & ?) == 0) || (Y == 0) --> ([ptrtoint] Y & ?) == 0
// ((? & [ptrtoint] Y) == 0) || (Y == 0) --> (? & [ptrtoint] Y) == 0
// (([ptrtoint] Y & ?) != 0) && (Y != 0) --> ([ptrtoint] Y & ?) != 0
// ((? & [ptrtoint] Y) != 0) && (Y != 0) --> (? & [ptrtoint] Y) != 0
if (match(X, m_c_And(m_Specific(Y), m_Value())) ||
    match(X, m_c_And(m_PtrToInt(m_Specific(Y)), m_Value())))
  return Cmp0;

return nullptr;
1459}

1461static Value *simplifyAndOfICmpsWithAdd(ICmpInst *Op0, ICmpInst *Op1) {
// (icmp (add V, C0), C1) & (icmp V, C0)
ICmpInst::Predicate Pred0, Pred1;
const APInt *C0, *C1;
Value *V;
if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
  return nullptr;

if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
  return nullptr;

auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
if (AddInst->getOperand(1) != Op1->getOperand(1))
  return nullptr;

Type *ITy = Op0->getType();
bool isNSW = AddInst->hasNoSignedWrap();
bool isNUW = AddInst->hasNoUnsignedWrap();

const APInt Delta = *C1 - *C0;
if (C0->isStrictlyPositive()) {
  if (Delta == 2) {
    if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT)
      return getFalse(ITy);
    if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW)
      return getFalse(ITy);
  }
  if (Delta == 1) {
    if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT)
      return getFalse(ITy);
    if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW)
      return getFalse(ITy);
  }
}
if (C0->getBoolValue() && isNUW) {
  if (Delta == 2)
    if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)
      return getFalse(ITy);
  if (Delta == 1)
    if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT)
      return getFalse(ITy);
}

return nullptr;
1505}

1507static Value *simplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true))
  return X;
if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/true))
  return X;

if (Value *X = simplifyAndOfICmpsWithSameOperands(Op0, Op1))
  return X;
if (Value *X = simplifyAndOfICmpsWithSameOperands(Op1, Op0))
  return X;

if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, true))
  return X;

if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, true))
  return X;

if (Value *X = simplifyAndOfICmpsWithAdd(Op0, Op1))
  return X;
if (Value *X = simplifyAndOfICmpsWithAdd(Op1, Op0))
  return X;

return nullptr;
1530}

1532static Value *simplifyOrOfICmpsWithAdd(ICmpInst *Op0, ICmpInst *Op1) {
// (icmp (add V, C0), C1) | (icmp V, C0)
ICmpInst::Predicate Pred0, Pred1;
const APInt *C0, *C1;
Value *V;
if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1))))
  return nullptr;

if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value())))
  return nullptr;

auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0));
if (AddInst->getOperand(1) != Op1->getOperand(1))
  return nullptr;

Type *ITy = Op0->getType();
bool isNSW = AddInst->hasNoSignedWrap();
bool isNUW = AddInst->hasNoUnsignedWrap();

const APInt Delta = *C1 - *C0;
if (C0->isStrictlyPositive()) {
  if (Delta == 2) {
    if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE)
      return getTrue(ITy);
    if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW)
      return getTrue(ITy);
  }
  if (Delta == 1) {
    if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE)
      return getTrue(ITy);
    if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW)
      return getTrue(ITy);
  }
}
if (C0->getBoolValue() && isNUW) {
  if (Delta == 2)
    if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE)
      return getTrue(ITy);
  if (Delta == 1)
    if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE)
      return getTrue(ITy);
}

return nullptr;
1576}

1578static Value *simplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false))
  return X;
if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/false))
  return X;

if (Value *X = simplifyOrOfICmpsWithSameOperands(Op0, Op1))
  return X;
if (Value *X = simplifyOrOfICmpsWithSameOperands(Op1, Op0))
  return X;

if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, false))
  return X;

if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, false))
  return X;

if (Value *X = simplifyOrOfICmpsWithAdd(Op0, Op1))
  return X;
if (Value *X = simplifyOrOfICmpsWithAdd(Op1, Op0))
  return X;

return nullptr;
1601}

1603static Value *simplifyAndOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS, bool IsAnd) {
Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1);
Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1);
if (LHS0->getType() != RHS0->getType())
  return nullptr;

FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
if ((PredL == FCmpInst::FCMP_ORD && PredR == FCmpInst::FCMP_ORD && IsAnd) ||
    (PredL == FCmpInst::FCMP_UNO && PredR == FCmpInst::FCMP_UNO && !IsAnd)) {
  // (fcmp ord NNAN, X) & (fcmp ord X, Y) --> fcmp ord X, Y
  // (fcmp ord NNAN, X) & (fcmp ord Y, X) --> fcmp ord Y, X
  // (fcmp ord X, NNAN) & (fcmp ord X, Y) --> fcmp ord X, Y
  // (fcmp ord X, NNAN) & (fcmp ord Y, X) --> fcmp ord Y, X
  // (fcmp uno NNAN, X) | (fcmp uno X, Y) --> fcmp uno X, Y
  // (fcmp uno NNAN, X) | (fcmp uno Y, X) --> fcmp uno Y, X
  // (fcmp uno X, NNAN) | (fcmp uno X, Y) --> fcmp uno X, Y
  // (fcmp uno X, NNAN) | (fcmp uno Y, X) --> fcmp uno Y, X
  if ((isKnownNeverNaN(LHS0) && (LHS1 == RHS0 || LHS1 == RHS1)) ||
      (isKnownNeverNaN(LHS1) && (LHS0 == RHS0 || LHS0 == RHS1)))
    return RHS;

  // (fcmp ord X, Y) & (fcmp ord NNAN, X) --> fcmp ord X, Y
  // (fcmp ord Y, X) & (fcmp ord NNAN, X) --> fcmp ord Y, X
  // (fcmp ord X, Y) & (fcmp ord X, NNAN) --> fcmp ord X, Y
  // (fcmp ord Y, X) & (fcmp ord X, NNAN) --> fcmp ord Y, X
  // (fcmp uno X, Y) | (fcmp uno NNAN, X) --> fcmp uno X, Y
  // (fcmp uno Y, X) | (fcmp uno NNAN, X) --> fcmp uno Y, X
  // (fcmp uno X, Y) | (fcmp uno X, NNAN) --> fcmp uno X, Y
  // (fcmp uno Y, X) | (fcmp uno X, NNAN) --> fcmp uno Y, X
  if ((isKnownNeverNaN(RHS0) && (RHS1 == LHS0 || RHS1 == LHS1)) ||
      (isKnownNeverNaN(RHS1) && (RHS0 == LHS0 || RHS0 == LHS1)))
    return LHS;
}

return nullptr;
1638}

1640static Value *simplifyAndOrOfCmps(Value *Op0, Value *Op1, bool IsAnd) {
// Look through casts of the 'and' operands to find compares.
auto *Cast0 = dyn_cast<CastInst>(Op0);
auto *Cast1 = dyn_cast<CastInst>(Op1);
if (Cast0 && Cast1 && Cast0->getOpcode() == Cast1->getOpcode() &&
    Cast0->getSrcTy() == Cast1->getSrcTy()) {
  Op0 = Cast0->getOperand(0);
  Op1 = Cast1->getOperand(0);
}

Value *V = nullptr;
auto *ICmp0 = dyn_cast<ICmpInst>(Op0);
auto *ICmp1 = dyn_cast<ICmpInst>(Op1);
if (ICmp0 && ICmp1)
  V = IsAnd ? simplifyAndOfICmps(ICmp0, ICmp1) :
              simplifyOrOfICmps(ICmp0, ICmp1);

auto *FCmp0 = dyn_cast<FCmpInst>(Op0);
auto *FCmp1 = dyn_cast<FCmpInst>(Op1);
if (FCmp0 && FCmp1)
  V = simplifyAndOrOfFCmps(FCmp0, FCmp1, IsAnd);

if (!V)
  return nullptr;
if (!Cast0)
  return V;

// If we looked through casts, we can only handle a constant simplification
// because we are not allowed to create a cast instruction here.
if (auto *C = dyn_cast<Constant>(V))
  return ConstantExpr::getCast(Cast0->getOpcode(), C, Cast0->getType());

return nullptr;
1673}

1675/// Given operands for an And, see if we can fold the result.
1676/// If not, this returns null.
1677static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                            unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Instruction::And, Op0, Op1, Q))
  return C;

// X & undef -> 0
if (match(Op1, m_Undef()))
  return Constant::getNullValue(Op0->getType());

// X & X = X
if (Op0 == Op1)
  return Op0;

// X & 0 = 0
if (match(Op1, m_Zero()))
  return Op1;

// X & -1 = X
if (match(Op1, m_AllOnes()))
  return Op0;

// A & ~A  =  ~A & A  =  0
if (match(Op0, m_Not(m_Specific(Op1))) ||
    match(Op1, m_Not(m_Specific(Op0))))
  return Constant::getNullValue(Op0->getType());

// (A | ?) & A = A
if (match(Op0, m_c_Or(m_Specific(Op1), m_Value())))
  return Op1;

// A & (A | ?) = A
if (match(Op1, m_c_Or(m_Specific(Op0), m_Value())))
  return Op0;

// A mask that only clears known zeros of a shifted value is a no-op.
Value *X;
const APInt *Mask;
const APInt *ShAmt;
if (match(Op1, m_APInt(Mask))) {
  // If all bits in the inverted and shifted mask are clear:
  // and (shl X, ShAmt), Mask --> shl X, ShAmt
  if (match(Op0, m_Shl(m_Value(X), m_APInt(ShAmt))) &&
      (~(*Mask)).lshr(*ShAmt).isNullValue())
    return Op0;

  // If all bits in the inverted and shifted mask are clear:
  // and (lshr X, ShAmt), Mask --> lshr X, ShAmt
  if (match(Op0, m_LShr(m_Value(X), m_APInt(ShAmt))) &&
      (~(*Mask)).shl(*ShAmt).isNullValue())
    return Op0;
}

// A & (-A) = A if A is a power of two or zero.
if (match(Op0, m_Neg(m_Specific(Op1))) ||
    match(Op1, m_Neg(m_Specific(Op0)))) {
  if (isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
                             Q.DT))
    return Op0;
  if (isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI,
                             Q.DT))
    return Op1;
}

if (Value *V = simplifyAndOrOfCmps(Op0, Op1, true))
  return V;

// Try some generic simplifications for associative operations.
if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
                                        MaxRecurse))
  return V;

// And distributes over Or.  Try some generic simplifications based on this.
if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
                           Q, MaxRecurse))
  return V;

// And distributes over Xor.  Try some generic simplifications based on this.
if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
                           Q, MaxRecurse))
  return V;

// If the operation is with the result of a select instruction, check whether
// operating on either branch of the select always yields the same value.
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
  if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
                                       MaxRecurse))
    return V;

// If the operation is with the result of a phi instruction, check whether
// operating on all incoming values of the phi always yields the same value.
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
  if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
                                    MaxRecurse))
    return V;

return nullptr;
1773}

1775Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
return ::SimplifyAndInst(Op0, Op1, Q, RecursionLimit);
1777}

1779/// Given operands for an Or, see if we can fold the result.
1780/// If not, this returns null.
1781static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                           unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Instruction::Or, Op0, Op1, Q))
  return C;

// X | undef -> -1
// X | -1 = -1
// Do not return Op1 because it may contain undef elements if it's a vector.
if (match(Op1, m_Undef()) || match(Op1, m_AllOnes()))
  return Constant::getAllOnesValue(Op0->getType());

// X | X = X
// X | 0 = X
if (Op0 == Op1 || match(Op1, m_Zero()))
  return Op0;

// A | ~A  =  ~A | A  =  -1
if (match(Op0, m_Not(m_Specific(Op1))) ||
    match(Op1, m_Not(m_Specific(Op0))))
  return Constant::getAllOnesValue(Op0->getType());

// (A & ?) | A = A
if (match(Op0, m_c_And(m_Specific(Op1), m_Value())))
  return Op1;

// A | (A & ?) = A
if (match(Op1, m_c_And(m_Specific(Op0), m_Value())))
  return Op0;

// ~(A & ?) | A = -1
if (match(Op0, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
  return Constant::getAllOnesValue(Op1->getType());

// A | ~(A & ?) = -1
if (match(Op1, m_Not(m_c_And(m_Specific(Op1), m_Value()))))
  return Constant::getAllOnesValue(Op0->getType());

Value *A, *B;
// (A & ~B) | (A ^ B) -> (A ^ B)
// (~B & A) | (A ^ B) -> (A ^ B)
// (A & ~B) | (B ^ A) -> (B ^ A)
// (~B & A) | (B ^ A) -> (B ^ A)
if (match(Op1, m_Xor(m_Value(A), m_Value(B))) &&
    (match(Op0, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
     match(Op0, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
  return Op1;

// Commute the 'or' operands.
// (A ^ B) | (A & ~B) -> (A ^ B)
// (A ^ B) | (~B & A) -> (A ^ B)
// (B ^ A) | (A & ~B) -> (B ^ A)
// (B ^ A) | (~B & A) -> (B ^ A)
if (match(Op0, m_Xor(m_Value(A), m_Value(B))) &&
    (match(Op1, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) ||
     match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B)))))
  return Op0;

// (A & B) | (~A ^ B) -> (~A ^ B)
// (B & A) | (~A ^ B) -> (~A ^ B)
// (A & B) | (B ^ ~A) -> (B ^ ~A)
// (B & A) | (B ^ ~A) -> (B ^ ~A)
if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
    (match(Op1, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
     match(Op1, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
  return Op1;

// (~A ^ B) | (A & B) -> (~A ^ B)
// (~A ^ B) | (B & A) -> (~A ^ B)
// (B ^ ~A) | (A & B) -> (B ^ ~A)
// (B ^ ~A) | (B & A) -> (B ^ ~A)
if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
    (match(Op0, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) ||
     match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B)))))
  return Op0;

if (Value *V = simplifyAndOrOfCmps(Op0, Op1, false))
  return V;

// Try some generic simplifications for associative operations.
if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
                                        MaxRecurse))
  return V;

// Or distributes over And.  Try some generic simplifications based on this.
if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
                           MaxRecurse))
  return V;

// If the operation is with the result of a select instruction, check whether
// operating on either branch of the select always yields the same value.
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
  if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
                                       MaxRecurse))
    return V;

// (A & C1)|(B & C2)
const APInt *C1, *C2;
if (match(Op0, m_And(m_Value(A), m_APInt(C1))) &&
    match(Op1, m_And(m_Value(B), m_APInt(C2)))) {
  if (*C1 == ~*C2) {
    // (A & C1)|(B & C2)
    // If we have: ((V + N) & C1) | (V & C2)
    // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
    // replace with V+N.
    Value *N;
    if (C2->isMask() && // C2 == 0+1+
        match(A, m_c_Add(m_Specific(B), m_Value(N)))) {
      // Add commutes, try both ways.
      if (MaskedValueIsZero(N, *C2, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
        return A;
    }
    // Or commutes, try both ways.
    if (C1->isMask() &&
        match(B, m_c_Add(m_Specific(A), m_Value(N)))) {
      // Add commutes, try both ways.
      if (MaskedValueIsZero(N, *C1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
        return B;
    }
  }
}

// If the operation is with the result of a phi instruction, check whether
// operating on all incoming values of the phi always yields the same value.
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
  if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
    return V;

return nullptr;
1909}

1911Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
return ::SimplifyOrInst(Op0, Op1, Q, RecursionLimit);
1913}

1915/// Given operands for a Xor, see if we can fold the result.
1916/// If not, this returns null.
1917static Value *SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                            unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Instruction::Xor, Op0, Op1, Q))
  return C;

// A ^ undef -> undef
if (match(Op1, m_Undef()))
  return Op1;

// A ^ 0 = A
if (match(Op1, m_Zero()))
  return Op0;

// A ^ A = 0
if (Op0 == Op1)
  return Constant::getNullValue(Op0->getType());

// A ^ ~A  =  ~A ^ A  =  -1
if (match(Op0, m_Not(m_Specific(Op1))) ||
    match(Op1, m_Not(m_Specific(Op0))))
  return Constant::getAllOnesValue(Op0->getType());

// Try some generic simplifications for associative operations.
if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
                                        MaxRecurse))
  return V;

// Threading Xor over selects and phi nodes is pointless, so don't bother.
// Threading over the select in "A ^ select(cond, B, C)" means evaluating
// "A^B" and "A^C" and seeing if they are equal; but they are equal if and
// only if B and C are equal.  If B and C are equal then (since we assume
// that operands have already been simplified) "select(cond, B, C)" should
// have been simplified to the common value of B and C already.  Analysing
// "A^B" and "A^C" thus gains nothing, but costs compile time.  Similarly
// for threading over phi nodes.

return nullptr;
1954}

1956Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
return ::SimplifyXorInst(Op0, Op1, Q, RecursionLimit);
1958}


1961static Type *GetCompareTy(Value *Op) {
return CmpInst::makeCmpResultType(Op->getType());
1963}

1965/// Rummage around inside V looking for something equivalent to the comparison
1966/// "LHS Pred RHS". Return such a value if found, otherwise return null.
1967/// Helper function for analyzing max/min idioms.
1968static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
                                       Value *LHS, Value *RHS) {
SelectInst *SI = dyn_cast<SelectInst>(V);
if (!SI)
  return nullptr;
CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
if (!Cmp)
  return nullptr;
Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
  return Cmp;
if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
    LHS == CmpRHS && RHS == CmpLHS)
  return Cmp;
return nullptr;
1983}

1985// A significant optimization not implemented here is assuming that alloca
1986// addresses are not equal to incoming argument values. They don't *alias*,
1987// as we say, but that doesn't mean they aren't equal, so we take a
1988// conservative approach.
1989//
1990// This is inspired in part by C++11 5.10p1:
1991//   "Two pointers of the same type compare equal if and only if they are both
1992//    null, both point to the same function, or both represent the same
1993//    address."
1994//
1995// This is pretty permissive.
1996//
1997// It's also partly due to C11 6.5.9p6:
1998//   "Two pointers compare equal if and only if both are null pointers, both are
1999//    pointers to the same object (including a pointer to an object and a
2000//    subobject at its beginning) or function, both are pointers to one past the
2001//    last element of the same array object, or one is a pointer to one past the
2002//    end of one array object and the other is a pointer to the start of a
2003//    different array object that happens to immediately follow the first array
2004//    object in the address space.)
2005//
2006// C11's version is more restrictive, however there's no reason why an argument
2007// couldn't be a one-past-the-end value for a stack object in the caller and be
2008// equal to the beginning of a stack object in the callee.
2009//
2010// If the C and C++ standards are ever made sufficiently restrictive in this
2011// area, it may be possible to update LLVM's semantics accordingly and reinstate
2012// this optimization.
2013static Constant *
2014computePointerICmp(const DataLayout &DL, const TargetLibraryInfo *TLI,
                 const DominatorTree *DT, CmpInst::Predicate Pred,
                 AssumptionCache *AC, const Instruction *CxtI,
                 Value *LHS, Value *RHS) {
// First, skip past any trivial no-ops.
LHS = LHS->stripPointerCasts();
RHS = RHS->stripPointerCasts();

// A non-null pointer is not equal to a null pointer.
if (llvm::isKnownNonZero(LHS, DL) && isa<ConstantPointerNull>(RHS) &&
    (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE))
  return ConstantInt::get(GetCompareTy(LHS),
                          !CmpInst::isTrueWhenEqual(Pred));

// We can only fold certain predicates on pointer comparisons.
switch (Pred) {
default:
  return nullptr;

  // Equality comaprisons are easy to fold.
case CmpInst::ICMP_EQ:
case CmpInst::ICMP_NE:
  break;

  // We can only handle unsigned relational comparisons because 'inbounds' on
  // a GEP only protects against unsigned wrapping.
case CmpInst::ICMP_UGT:
case CmpInst::ICMP_UGE:
case CmpInst::ICMP_ULT:
case CmpInst::ICMP_ULE:
  // However, we have to switch them to their signed variants to handle
  // negative indices from the base pointer.
  Pred = ICmpInst::getSignedPredicate(Pred);
  break;
}

// Strip off any constant offsets so that we can reason about them.
// It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
// here and compare base addresses like AliasAnalysis does, however there are
// numerous hazards. AliasAnalysis and its utilities rely on special rules
// governing loads and stores which don't apply to icmps. Also, AliasAnalysis
// doesn't need to guarantee pointer inequality when it says NoAlias.
Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS);
Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS);

// If LHS and RHS are related via constant offsets to the same base
// value, we can replace it with an icmp which just compares the offsets.
if (LHS == RHS)
  return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);

// Various optimizations for (in)equality comparisons.
if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) {
  // Different non-empty allocations that exist at the same time have
  // different addresses (if the program can tell). Global variables always
  // exist, so they always exist during the lifetime of each other and all
  // allocas. Two different allocas usually have different addresses...
  //
  // However, if there's an @llvm.stackrestore dynamically in between two
  // allocas, they may have the same address. It's tempting to reduce the
  // scope of the problem by only looking at *static* allocas here. That would
  // cover the majority of allocas while significantly reducing the likelihood
  // of having an @llvm.stackrestore pop up in the middle. However, it's not
  // actually impossible for an @llvm.stackrestore to pop up in the middle of
  // an entry block. Also, if we have a block that's not attached to a
  // function, we can't tell if it's "static" under the current definition.
  // Theoretically, this problem could be fixed by creating a new kind of
  // instruction kind specifically for static allocas. Such a new instruction
  // could be required to be at the top of the entry block, thus preventing it
  // from being subject to a @llvm.stackrestore. Instcombine could even
  // convert regular allocas into these special allocas. It'd be nifty.
  // However, until then, this problem remains open.
  //
  // So, we'll assume that two non-empty allocas have different addresses
  // for now.
  //
  // With all that, if the offsets are within the bounds of their allocations
  // (and not one-past-the-end! so we can't use inbounds!), and their
  // allocations aren't the same, the pointers are not equal.
  //
  // Note that it's not necessary to check for LHS being a global variable
  // address, due to canonicalization and constant folding.
  if (isa<AllocaInst>(LHS) &&
      (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) {
    ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
    ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
    uint64_t LHSSize, RHSSize;
    if (LHSOffsetCI && RHSOffsetCI &&
        getObjectSize(LHS, LHSSize, DL, TLI) &&
        getObjectSize(RHS, RHSSize, DL, TLI)) {
      const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
      const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
      if (!LHSOffsetValue.isNegative() &&
          !RHSOffsetValue.isNegative() &&
          LHSOffsetValue.ult(LHSSize) &&
          RHSOffsetValue.ult(RHSSize)) {
        return ConstantInt::get(GetCompareTy(LHS),
                                !CmpInst::isTrueWhenEqual(Pred));
      }
    }

    // Repeat the above check but this time without depending on DataLayout
    // or being able to compute a precise size.
    if (!cast<PointerType>(LHS->getType())->isEmptyTy() &&
        !cast<PointerType>(RHS->getType())->isEmptyTy() &&
        LHSOffset->isNullValue() &&
        RHSOffset->isNullValue())
      return ConstantInt::get(GetCompareTy(LHS),
                              !CmpInst::isTrueWhenEqual(Pred));
  }

  // Even if an non-inbounds GEP occurs along the path we can still optimize
  // equality comparisons concerning the result. We avoid walking the whole
  // chain again by starting where the last calls to
  // stripAndComputeConstantOffsets left off and accumulate the offsets.
  Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true);
  Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true);
  if (LHS == RHS)
    return ConstantExpr::getICmp(Pred,
                                 ConstantExpr::getAdd(LHSOffset, LHSNoBound),
                                 ConstantExpr::getAdd(RHSOffset, RHSNoBound));

  // If one side of the equality comparison must come from a noalias call
  // (meaning a system memory allocation function), and the other side must
  // come from a pointer that cannot overlap with dynamically-allocated
  // memory within the lifetime of the current function (allocas, byval
  // arguments, globals), then determine the comparison result here.
  SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
  GetUnderlyingObjects(LHS, LHSUObjs, DL);
  GetUnderlyingObjects(RHS, RHSUObjs, DL);

  // Is the set of underlying objects all noalias calls?
  auto IsNAC = [](ArrayRef<Value *> Objects) {
    return all_of(Objects, isNoAliasCall);
  };

  // Is the set of underlying objects all things which must be disjoint from
  // noalias calls. For allocas, we consider only static ones (dynamic
  // allocas might be transformed into calls to malloc not simultaneously
  // live with the compared-to allocation). For globals, we exclude symbols
  // that might be resolve lazily to symbols in another dynamically-loaded
  // library (and, thus, could be malloc'ed by the implementation).
  auto IsAllocDisjoint = [](ArrayRef<Value *> Objects) {
    return all_of(Objects, [](Value *V) {
      if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
        return AI->getParent() && AI->getFunction() && AI->isStaticAlloca();
      if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
        return (GV->hasLocalLinkage() || GV->hasHiddenVisibility() ||
                GV->hasProtectedVisibility() || GV->hasGlobalUnnamedAddr()) &&
               !GV->isThreadLocal();
      if (const Argument *A = dyn_cast<Argument>(V))
        return A->hasByValAttr();
      return false;
    });
  };

  if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) ||
      (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs)))
      return ConstantInt::get(GetCompareTy(LHS),
                              !CmpInst::isTrueWhenEqual(Pred));

  // Fold comparisons for non-escaping pointer even if the allocation call
  // cannot be elided. We cannot fold malloc comparison to null. Also, the
  // dynamic allocation call could be either of the operands.
  Value *MI = nullptr;
  if (isAllocLikeFn(LHS, TLI) &&
      llvm::isKnownNonZero(RHS, DL, 0, nullptr, CxtI, DT))
    MI = LHS;
  else if (isAllocLikeFn(RHS, TLI) &&
           llvm::isKnownNonZero(LHS, DL, 0, nullptr, CxtI, DT))
    MI = RHS;
  // FIXME: We should also fold the compare when the pointer escapes, but the
  // compare dominates the pointer escape
  if (MI && !PointerMayBeCaptured(MI, true, true))
    return ConstantInt::get(GetCompareTy(LHS),
                            CmpInst::isFalseWhenEqual(Pred));
}

// Otherwise, fail.
return nullptr;
2193}

2195/// Fold an icmp when its operands have i1 scalar type.
2196static Value *simplifyICmpOfBools(CmpInst::Predicate Pred, Value *LHS,
                                Value *RHS, const SimplifyQuery &Q) {
Type *ITy = GetCompareTy(LHS); // The return type.
Type *OpTy = LHS->getType();   // The operand type.
if (!OpTy->isIntOrIntVectorTy(1))
  return nullptr;

// A boolean compared to true/false can be simplified in 14 out of the 20
// (10 predicates * 2 constants) possible combinations. Cases not handled here
// require a 'not' of the LHS, so those must be transformed in InstCombine.
if (match(RHS, m_Zero())) {
  switch (Pred) {
  case CmpInst::ICMP_NE:  // X !=  0 -> X
  case CmpInst::ICMP_UGT: // X >u  0 -> X
  case CmpInst::ICMP_SLT: // X <s  0 -> X
    return LHS;

  case CmpInst::ICMP_ULT: // X <u  0 -> false
  case CmpInst::ICMP_SGT: // X >s  0 -> false
    return getFalse(ITy);

  case CmpInst::ICMP_UGE: // X >=u 0 -> true
  case CmpInst::ICMP_SLE: // X <=s 0 -> true
    return getTrue(ITy);

  default: break;
  }
} else if (match(RHS, m_One())) {
  switch (Pred) {
  case CmpInst::ICMP_EQ:  // X ==   1 -> X
  case CmpInst::ICMP_UGE: // X >=u  1 -> X
  case CmpInst::ICMP_SLE: // X <=s -1 -> X
    return LHS;

  case CmpInst::ICMP_UGT: // X >u   1 -> false
  case CmpInst::ICMP_SLT: // X <s  -1 -> false
    return getFalse(ITy);

  case CmpInst::ICMP_ULE: // X <=u  1 -> true
  case CmpInst::ICMP_SGE: // X >=s -1 -> true
    return getTrue(ITy);

  default: break;
  }
}

switch (Pred) {
default:
  break;
case ICmpInst::ICMP_UGE:
  if (isImpliedCondition(RHS, LHS, Q.DL).getValueOr(false))
    return getTrue(ITy);
  break;
case ICmpInst::ICMP_SGE:
  /// For signed comparison, the values for an i1 are 0 and -1
  /// respectively. This maps into a truth table of:
  /// LHS | RHS | LHS >=s RHS   | LHS implies RHS
  ///  0  |  0  |  1 (0 >= 0)   |  1
  ///  0  |  1  |  1 (0 >= -1)  |  1
  ///  1  |  0  |  0 (-1 >= 0)  |  0
  ///  1  |  1  |  1 (-1 >= -1) |  1
  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
    return getTrue(ITy);
  break;
case ICmpInst::ICMP_ULE:
  if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false))
    return getTrue(ITy);
  break;
}

return nullptr;
2267}

2269/// Try hard to fold icmp with zero RHS because this is a common case.
2270static Value *simplifyICmpWithZero(CmpInst::Predicate Pred, Value *LHS,
                                 Value *RHS, const SimplifyQuery &Q) {
if (!match(RHS, m_Zero()))
  return nullptr;

Type *ITy = GetCompareTy(LHS); // The return type.
switch (Pred) {
default:
  llvm_unreachable("Unknown ICmp predicate!")::llvm::llvm_unreachable_internal("Unknown ICmp predicate!", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 2278);
case ICmpInst::ICMP_ULT:
  return getFalse(ITy);
case ICmpInst::ICMP_UGE:
  return getTrue(ITy);
case ICmpInst::ICMP_EQ:
case ICmpInst::ICMP_ULE:
  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
    return getFalse(ITy);
  break;
case ICmpInst::ICMP_NE:
case ICmpInst::ICMP_UGT:
  if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
    return getTrue(ITy);
  break;
case ICmpInst::ICMP_SLT: {
  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
  if (LHSKnown.isNegative())
    return getTrue(ITy);
  if (LHSKnown.isNonNegative())
    return getFalse(ITy);
  break;
}
case ICmpInst::ICMP_SLE: {
  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
  if (LHSKnown.isNegative())
    return getTrue(ITy);
  if (LHSKnown.isNonNegative() &&
      isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
    return getFalse(ITy);
  break;
}
case ICmpInst::ICMP_SGE: {
  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
  if (LHSKnown.isNegative())
    return getFalse(ITy);
  if (LHSKnown.isNonNegative())
    return getTrue(ITy);
  break;
}
case ICmpInst::ICMP_SGT: {
  KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
  if (LHSKnown.isNegative())
    return getFalse(ITy);
  if (LHSKnown.isNonNegative() &&
      isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT))
    return getTrue(ITy);
  break;
}
}

return nullptr;
2330}

2332/// Many binary operators with a constant operand have an easy-to-compute
2333/// range of outputs. This can be used to fold a comparison to always true or
2334/// always false.
2335static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
unsigned Width = Lower.getBitWidth();
const APInt *C;
switch (BO.getOpcode()) {
case Instruction::Add:
  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
    // FIXME: If we have both nuw and nsw, we should reduce the range further.
    if (BO.hasNoUnsignedWrap()) {
      // 'add nuw x, C' produces [C, UINT_MAX].
      Lower = *C;
    } else if (BO.hasNoSignedWrap()) {
      if (C->isNegative()) {
        // 'add nsw x, -C' produces [SINT_MIN, SINT_MAX - C].
        Lower = APInt::getSignedMinValue(Width);
        Upper = APInt::getSignedMaxValue(Width) + *C + 1;
      } else {
        // 'add nsw x, +C' produces [SINT_MIN + C, SINT_MAX].
        Lower = APInt::getSignedMinValue(Width) + *C;
        Upper = APInt::getSignedMaxValue(Width) + 1;
      }
    }
  }
  break;

case Instruction::And:
  if (match(BO.getOperand(1), m_APInt(C)))
    // 'and x, C' produces [0, C].
    Upper = *C + 1;
  break;

case Instruction::Or:
  if (match(BO.getOperand(1), m_APInt(C)))
    // 'or x, C' produces [C, UINT_MAX].
    Lower = *C;
  break;

case Instruction::AShr:
  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
    // 'ashr x, C' produces [INT_MIN >> C, INT_MAX >> C].
    Lower = APInt::getSignedMinValue(Width).ashr(*C);
    Upper = APInt::getSignedMaxValue(Width).ashr(*C) + 1;
  } else if (match(BO.getOperand(0), m_APInt(C))) {
    unsigned ShiftAmount = Width - 1;
    if (!C->isNullValue() && BO.isExact())
      ShiftAmount = C->countTrailingZeros();
    if (C->isNegative()) {
      // 'ashr C, x' produces [C, C >> (Width-1)]
      Lower = *C;
      Upper = C->ashr(ShiftAmount) + 1;
    } else {
      // 'ashr C, x' produces [C >> (Width-1), C]
      Lower = C->ashr(ShiftAmount);
      Upper = *C + 1;
    }
  }
  break;

case Instruction::LShr:
  if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
    // 'lshr x, C' produces [0, UINT_MAX >> C].
    Upper = APInt::getAllOnesValue(Width).lshr(*C) + 1;
  } else if (match(BO.getOperand(0), m_APInt(C))) {
    // 'lshr C, x' produces [C >> (Width-1), C].
    unsigned ShiftAmount = Width - 1;
    if (!C->isNullValue() && BO.isExact())
      ShiftAmount = C->countTrailingZeros();
    Lower = C->lshr(ShiftAmount);
    Upper = *C + 1;
  }
  break;

case Instruction::Shl:
  if (match(BO.getOperand(0), m_APInt(C))) {
    if (BO.hasNoUnsignedWrap()) {
      // 'shl nuw C, x' produces [C, C << CLZ(C)]
      Lower = *C;
      Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
    } else if (BO.hasNoSignedWrap()) { // TODO: What if both nuw+nsw?
      if (C->isNegative()) {
        // 'shl nsw C, x' produces [C << CLO(C)-1, C]
        unsigned ShiftAmount = C->countLeadingOnes() - 1;
        Lower = C->shl(ShiftAmount);
        Upper = *C + 1;
      } else {
        // 'shl nsw C, x' produces [C, C << CLZ(C)-1]
        unsigned ShiftAmount = C->countLeadingZeros() - 1;
        Lower = *C;
        Upper = C->shl(ShiftAmount) + 1;
      }
    }
  }
  break;

case Instruction::SDiv:
  if (match(BO.getOperand(1), m_APInt(C))) {
    APInt IntMin = APInt::getSignedMinValue(Width);
    APInt IntMax = APInt::getSignedMaxValue(Width);
    if (C->isAllOnesValue()) {
      // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
      //    where C != -1 and C != 0 and C != 1
      Lower = IntMin + 1;
      Upper = IntMax + 1;
    } else if (C->countLeadingZeros() < Width - 1) {
      // 'sdiv x, C' produces [INT_MIN / C, INT_MAX / C]
      //    where C != -1 and C != 0 and C != 1
      Lower = IntMin.sdiv(*C);
      Upper = IntMax.sdiv(*C);
      if (Lower.sgt(Upper))
        std::swap(Lower, Upper);
      Upper = Upper + 1;
      assert(Upper != Lower && "Upper part of range has wrapped!")(static_cast <bool> (Upper != Lower && "Upper part of range has wrapped!"
) ? void (0) : __assert_fail ("Upper != Lower && \"Upper part of range has wrapped!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 2445, __extension__ __PRETTY_FUNCTION__));
    }
  } else if (match(BO.getOperand(0), m_APInt(C))) {
    if (C->isMinSignedValue()) {
      // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
      Lower = *C;
      Upper = Lower.lshr(1) + 1;
    } else {
      // 'sdiv C, x' produces [-|C|, |C|].
      Upper = C->abs() + 1;
      Lower = (-Upper) + 1;
    }
  }
  break;

case Instruction::UDiv:
  if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
    // 'udiv x, C' produces [0, UINT_MAX / C].
    Upper = APInt::getMaxValue(Width).udiv(*C) + 1;
  } else if (match(BO.getOperand(0), m_APInt(C))) {
    // 'udiv C, x' produces [0, C].
    Upper = *C + 1;
  }
  break;

case Instruction::SRem:
  if (match(BO.getOperand(1), m_APInt(C))) {
    // 'srem x, C' produces (-|C|, |C|).
    Upper = C->abs();
    Lower = (-Upper) + 1;
  }
  break;

case Instruction::URem:
  if (match(BO.getOperand(1), m_APInt(C)))
    // 'urem x, C' produces [0, C).
    Upper = *C;
  break;

default:
  break;
}
2487}

2489static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS,
                                     Value *RHS) {
Type *ITy = GetCompareTy(RHS); // The return type.

Value *X;
// Sign-bit checks can be optimized to true/false after unsigned
// floating-point casts:
// icmp slt (bitcast (uitofp X)),  0 --> false
// icmp sgt (bitcast (uitofp X)), -1 --> true
if (match(LHS, m_BitCast(m_UIToFP(m_Value(X))))) {
  if (Pred == ICmpInst::ICMP_SLT && match(RHS, m_Zero()))
    return ConstantInt::getFalse(ITy);
  if (Pred == ICmpInst::ICMP_SGT && match(RHS, m_AllOnes()))
    return ConstantInt::getTrue(ITy);
}

const APInt *C;
if (!match(RHS, m_APInt(C)))
  return nullptr;

// Rule out tautological comparisons (eg., ult 0 or uge 0).
ConstantRange RHS_CR = ConstantRange::makeExactICmpRegion(Pred, *C);
if (RHS_CR.isEmptySet())
  return ConstantInt::getFalse(ITy);
if (RHS_CR.isFullSet())
  return ConstantInt::getTrue(ITy);

// Find the range of possible values for binary operators.
unsigned Width = C->getBitWidth();
APInt Lower = APInt(Width, 0);
APInt Upper = APInt(Width, 0);
if (auto *BO = dyn_cast<BinaryOperator>(LHS))
  setLimitsForBinOp(*BO, Lower, Upper);

ConstantRange LHS_CR =
    Lower != Upper ? ConstantRange(Lower, Upper) : ConstantRange(Width, true);

if (auto *I = dyn_cast<Instruction>(LHS))
  if (auto *Ranges = I->getMetadata(LLVMContext::MD_range))
    LHS_CR = LHS_CR.intersectWith(getConstantRangeFromMetadata(*Ranges));

if (!LHS_CR.isFullSet()) {
  if (RHS_CR.contains(LHS_CR))
    return ConstantInt::getTrue(ITy);
  if (RHS_CR.inverse().contains(LHS_CR))
    return ConstantInt::getFalse(ITy);
}

return nullptr;
2538}

2540/// TODO: A large part of this logic is duplicated in InstCombine's
2541/// foldICmpBinOp(). We should be able to share that and avoid the code
2542/// duplication.
2543static Value *simplifyICmpWithBinOp(CmpInst::Predicate Pred, Value *LHS,
                                  Value *RHS, const SimplifyQuery &Q,
                                  unsigned MaxRecurse) {
Type *ITy = GetCompareTy(LHS); // The return type.

BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
if (MaxRecurse && (LBO || RBO)) {
  // Analyze the case when either LHS or RHS is an add instruction.
  Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
  // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
  bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
  if (LBO && LBO->getOpcode() == Instruction::Add) {
    A = LBO->getOperand(0);
    B = LBO->getOperand(1);
    NoLHSWrapProblem =
        ICmpInst::isEquality(Pred) ||
        (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
        (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
  }
  if (RBO && RBO->getOpcode() == Instruction::Add) {
    C = RBO->getOperand(0);
    D = RBO->getOperand(1);
    NoRHSWrapProblem =
        ICmpInst::isEquality(Pred) ||
        (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
        (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
  }

  // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
  if ((A == RHS || B == RHS) && NoLHSWrapProblem)
    if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
                                    Constant::getNullValue(RHS->getType()), Q,
                                    MaxRecurse - 1))
      return V;

  // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
  if ((C == LHS || D == LHS) && NoRHSWrapProblem)
    if (Value *V =
            SimplifyICmpInst(Pred, Constant::getNullValue(LHS->getType()),
                             C == LHS ? D : C, Q, MaxRecurse - 1))
      return V;

  // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
  if (A && C && (A == C || A == D || B == C || B == D) && NoLHSWrapProblem &&
      NoRHSWrapProblem) {
    // Determine Y and Z in the form icmp (X+Y), (X+Z).
    Value *Y, *Z;
    if (A == C) {
      // C + B == C + D  ->  B == D
      Y = B;
      Z = D;
    } else if (A == D) {
      // D + B == C + D  ->  B == C
      Y = B;
      Z = C;
    } else if (B == C) {
      // A + C == C + D  ->  A == D
      Y = A;
      Z = D;
    } else {
      assert(B == D)(static_cast <bool> (B == D) ? void (0) : __assert_fail
 ("B == D", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 2604, __extension__ __PRETTY_FUNCTION__));
      // A + D == C + D  ->  A == C
      Y = A;
      Z = C;
    }
    if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse - 1))
      return V;
  }
}

{
  Value *Y = nullptr;
  // icmp pred (or X, Y), X
  if (LBO && match(LBO, m_c_Or(m_Value(Y), m_Specific(RHS)))) {
    if (Pred == ICmpInst::ICMP_ULT)
      return getFalse(ITy);
    if (Pred == ICmpInst::ICMP_UGE)
      return getTrue(ITy);

    if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SGE) {
      KnownBits RHSKnown = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
      KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
      if (RHSKnown.isNonNegative() && YKnown.isNegative())
        return Pred == ICmpInst::ICMP_SLT ? getTrue(ITy) : getFalse(ITy);
      if (RHSKnown.isNegative() || YKnown.isNonNegative())
        return Pred == ICmpInst::ICMP_SLT ? getFalse(ITy) : getTrue(ITy);
    }
  }
  // icmp pred X, (or X, Y)
  if (RBO && match(RBO, m_c_Or(m_Value(Y), m_Specific(LHS)))) {
    if (Pred == ICmpInst::ICMP_ULE)
      return getTrue(ITy);
    if (Pred == ICmpInst::ICMP_UGT)
      return getFalse(ITy);

    if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE) {
      KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
      KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
      if (LHSKnown.isNonNegative() && YKnown.isNegative())
        return Pred == ICmpInst::ICMP_SGT ? getTrue(ITy) : getFalse(ITy);
      if (LHSKnown.isNegative() || YKnown.isNonNegative())
        return Pred == ICmpInst::ICMP_SGT ? getFalse(ITy) : getTrue(ITy);
    }
  }
}

// icmp pred (and X, Y), X
if (LBO && match(LBO, m_c_And(m_Value(), m_Specific(RHS)))) {
  if (Pred == ICmpInst::ICMP_UGT)
    return getFalse(ITy);
  if (Pred == ICmpInst::ICMP_ULE)
    return getTrue(ITy);
}
// icmp pred X, (and X, Y)
if (RBO && match(RBO, m_c_And(m_Value(), m_Specific(LHS)))) {
  if (Pred == ICmpInst::ICMP_UGE)
    return getTrue(ITy);
  if (Pred == ICmpInst::ICMP_ULT)
    return getFalse(ITy);
}

// 0 - (zext X) pred C
if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
  if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
    if (RHSC->getValue().isStrictlyPositive()) {
      if (Pred == ICmpInst::ICMP_SLT)
        return ConstantInt::getTrue(RHSC->getContext());
      if (Pred == ICmpInst::ICMP_SGE)
        return ConstantInt::getFalse(RHSC->getContext());
      if (Pred == ICmpInst::ICMP_EQ)
        return ConstantInt::getFalse(RHSC->getContext());
      if (Pred == ICmpInst::ICMP_NE)
        return ConstantInt::getTrue(RHSC->getContext());
    }
    if (RHSC->getValue().isNonNegative()) {
      if (Pred == ICmpInst::ICMP_SLE)
        return ConstantInt::getTrue(RHSC->getContext());
      if (Pred == ICmpInst::ICMP_SGT)
        return ConstantInt::getFalse(RHSC->getContext());
    }
  }
}

// icmp pred (urem X, Y), Y
if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
  switch (Pred) {
  default:
    break;
  case ICmpInst::ICMP_SGT:
  case ICmpInst::ICMP_SGE: {
    KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
    if (!Known.isNonNegative())
      break;
    LLVM_FALLTHROUGH[[clang::fallthrough]];
  }
  case ICmpInst::ICMP_EQ:
  case ICmpInst::ICMP_UGT:
  case ICmpInst::ICMP_UGE:
    return getFalse(ITy);
  case ICmpInst::ICMP_SLT:
  case ICmpInst::ICMP_SLE: {
    KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
    if (!Known.isNonNegative())
      break;
    LLVM_FALLTHROUGH[[clang::fallthrough]];
  }
  case ICmpInst::ICMP_NE:
  case ICmpInst::ICMP_ULT:
  case ICmpInst::ICMP_ULE:
    return getTrue(ITy);
  }
}

// icmp pred X, (urem Y, X)
if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
  switch (Pred) {
  default:
    break;
  case ICmpInst::ICMP_SGT:
  case ICmpInst::ICMP_SGE: {
    KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
    if (!Known.isNonNegative())
      break;
    LLVM_FALLTHROUGH[[clang::fallthrough]];
  }
  case ICmpInst::ICMP_NE:
  case ICmpInst::ICMP_UGT:
  case ICmpInst::ICMP_UGE:
    return getTrue(ITy);
  case ICmpInst::ICMP_SLT:
  case ICmpInst::ICMP_SLE: {
    KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
    if (!Known.isNonNegative())
      break;
    LLVM_FALLTHROUGH[[clang::fallthrough]];
  }
  case ICmpInst::ICMP_EQ:
  case ICmpInst::ICMP_ULT:
  case ICmpInst::ICMP_ULE:
    return getFalse(ITy);
  }
}

// x >> y <=u x
// x udiv y <=u x.
if (LBO && (match(LBO, m_LShr(m_Specific(RHS), m_Value())) ||
            match(LBO, m_UDiv(m_Specific(RHS), m_Value())))) {
  // icmp pred (X op Y), X
  if (Pred == ICmpInst::ICMP_UGT)
    return getFalse(ITy);
  if (Pred == ICmpInst::ICMP_ULE)
    return getTrue(ITy);
}

// x >=u x >> y
// x >=u x udiv y.
if (RBO && (match(RBO, m_LShr(m_Specific(LHS), m_Value())) ||
            match(RBO, m_UDiv(m_Specific(LHS), m_Value())))) {
  // icmp pred X, (X op Y)
  if (Pred == ICmpInst::ICMP_ULT)
    return getFalse(ITy);
  if (Pred == ICmpInst::ICMP_UGE)
    return getTrue(ITy);
}

// handle:
//   CI2 << X == CI
//   CI2 << X != CI
//
//   where CI2 is a power of 2 and CI isn't
if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
  const APInt *CI2Val, *CIVal = &CI->getValue();
  if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
      CI2Val->isPowerOf2()) {
    if (!CIVal->isPowerOf2()) {
      // CI2 << X can equal zero in some circumstances,
      // this simplification is unsafe if CI is zero.
      //
      // We know it is safe if:
      // - The shift is nsw, we can't shift out the one bit.
      // - The shift is nuw, we can't shift out the one bit.
      // - CI2 is one
      // - CI isn't zero
      if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
          CI2Val->isOneValue() || !CI->isZero()) {
        if (Pred == ICmpInst::ICMP_EQ)
          return ConstantInt::getFalse(RHS->getContext());
        if (Pred == ICmpInst::ICMP_NE)
          return ConstantInt::getTrue(RHS->getContext());
      }
    }
    if (CIVal->isSignMask() && CI2Val->isOneValue()) {
      if (Pred == ICmpInst::ICMP_UGT)
        return ConstantInt::getFalse(RHS->getContext());
      if (Pred == ICmpInst::ICMP_ULE)
        return ConstantInt::getTrue(RHS->getContext());
    }
  }
}

if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
    LBO->getOperand(1) == RBO->getOperand(1)) {
  switch (LBO->getOpcode()) {
  default:
    break;
  case Instruction::UDiv:
  case Instruction::LShr:
    if (ICmpInst::isSigned(Pred) || !LBO->isExact() || !RBO->isExact())
      break;
    if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
                                    RBO->getOperand(0), Q, MaxRecurse - 1))
        return V;
    break;
  case Instruction::SDiv:
    if (!ICmpInst::isEquality(Pred) || !LBO->isExact() || !RBO->isExact())
      break;
    if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
                                    RBO->getOperand(0), Q, MaxRecurse - 1))
      return V;
    break;
  case Instruction::AShr:
    if (!LBO->isExact() || !RBO->isExact())
      break;
    if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
                                    RBO->getOperand(0), Q, MaxRecurse - 1))
      return V;
    break;
  case Instruction::Shl: {
    bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
    bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
    if (!NUW && !NSW)
      break;
    if (!NSW && ICmpInst::isSigned(Pred))
      break;
    if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
                                    RBO->getOperand(0), Q, MaxRecurse - 1))
      return V;
    break;
  }
  }
}
return nullptr;
2846}

2848/// Simplify integer comparisons where at least one operand of the compare
2849/// matches an integer min/max idiom.
2850static Value *simplifyICmpWithMinMax(CmpInst::Predicate Pred, Value *LHS,
                                   Value *RHS, const SimplifyQuery &Q,
                                   unsigned MaxRecurse) {
Type *ITy = GetCompareTy(LHS); // The return type.
Value *A, *B;
CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".

// Signed variants on "max(a,b)>=a -> true".
if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
  if (A != RHS)
    std::swap(A, B);       // smax(A, B) pred A.
  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
  // We analyze this as smax(A, B) pred A.
  P = Pred;
} else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
           (A == LHS || B == LHS)) {
  if (A != LHS)
    std::swap(A, B);       // A pred smax(A, B).
  EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
  // We analyze this as smax(A, B) swapped-pred A.
  P = CmpInst::getSwappedPredicate(Pred);
} else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
           (A == RHS || B == RHS)) {
  if (A != RHS)
    std::swap(A, B);       // smin(A, B) pred A.
  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
  // We analyze this as smax(-A, -B) swapped-pred -A.
  // Note that we do not need to actually form -A or -B thanks to EqP.
  P = CmpInst::getSwappedPredicate(Pred);
} else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
           (A == LHS || B == LHS)) {
  if (A != LHS)
    std::swap(A, B);       // A pred smin(A, B).
  EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
  // We analyze this as smax(-A, -B) pred -A.
  // Note that we do not need to actually form -A or -B thanks to EqP.
  P = Pred;
}
if (P != CmpInst::BAD_ICMP_PREDICATE) {
  // Cases correspond to "max(A, B) p A".
  switch (P) {
  default:
    break;
  case CmpInst::ICMP_EQ:
  case CmpInst::ICMP_SLE:
    // Equivalent to "A EqP B".  This may be the same as the condition tested
    // in the max/min; if so, we can just return that.
    if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
      return V;
    if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
      return V;
    // Otherwise, see if "A EqP B" simplifies.
    if (MaxRecurse)
      if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
        return V;
    break;
  case CmpInst::ICMP_NE:
  case CmpInst::ICMP_SGT: {
    CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
    // Equivalent to "A InvEqP B".  This may be the same as the condition
    // tested in the max/min; if so, we can just return that.
    if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
      return V;
    if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
      return V;
    // Otherwise, see if "A InvEqP B" simplifies.
    if (MaxRecurse)
      if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
        return V;
    break;
  }
  case CmpInst::ICMP_SGE:
    // Always true.
    return getTrue(ITy);
  case CmpInst::ICMP_SLT:
    // Always false.
    return getFalse(ITy);
  }
}

// Unsigned variants on "max(a,b)>=a -> true".
P = CmpInst::BAD_ICMP_PREDICATE;
if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
  if (A != RHS)
    std::swap(A, B);       // umax(A, B) pred A.
  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
  // We analyze this as umax(A, B) pred A.
  P = Pred;
} else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
           (A == LHS || B == LHS)) {
  if (A != LHS)
    std::swap(A, B);       // A pred umax(A, B).
  EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
  // We analyze this as umax(A, B) swapped-pred A.
  P = CmpInst::getSwappedPredicate(Pred);
} else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
           (A == RHS || B == RHS)) {
  if (A != RHS)
    std::swap(A, B);       // umin(A, B) pred A.
  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
  // We analyze this as umax(-A, -B) swapped-pred -A.
  // Note that we do not need to actually form -A or -B thanks to EqP.
  P = CmpInst::getSwappedPredicate(Pred);
} else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
           (A == LHS || B == LHS)) {
  if (A != LHS)
    std::swap(A, B);       // A pred umin(A, B).
  EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
  // We analyze this as umax(-A, -B) pred -A.
  // Note that we do not need to actually form -A or -B thanks to EqP.
  P = Pred;
}
if (P != CmpInst::BAD_ICMP_PREDICATE) {
  // Cases correspond to "max(A, B) p A".
  switch (P) {
  default:
    break;
  case CmpInst::ICMP_EQ:
  case CmpInst::ICMP_ULE:
    // Equivalent to "A EqP B".  This may be the same as the condition tested
    // in the max/min; if so, we can just return that.
    if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
      return V;
    if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
      return V;
    // Otherwise, see if "A EqP B" simplifies.
    if (MaxRecurse)
      if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1))
        return V;
    break;
  case CmpInst::ICMP_NE:
  case CmpInst::ICMP_UGT: {
    CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
    // Equivalent to "A InvEqP B".  This may be the same as the condition
    // tested in the max/min; if so, we can just return that.
    if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
      return V;
    if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
      return V;
    // Otherwise, see if "A InvEqP B" simplifies.
    if (MaxRecurse)
      if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1))
        return V;
    break;
  }
  case CmpInst::ICMP_UGE:
    // Always true.
    return getTrue(ITy);
  case CmpInst::ICMP_ULT:
    // Always false.
    return getFalse(ITy);
  }
}

// Variants on "max(x,y) >= min(x,z)".
Value *C, *D;
if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
    match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
    (A == C || A == D || B == C || B == D)) {
  // max(x, ?) pred min(x, ?).
  if (Pred == CmpInst::ICMP_SGE)
    // Always true.
    return getTrue(ITy);
  if (Pred == CmpInst::ICMP_SLT)
    // Always false.
    return getFalse(ITy);
} else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
           match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
           (A == C || A == D || B == C || B == D)) {
  // min(x, ?) pred max(x, ?).
  if (Pred == CmpInst::ICMP_SLE)
    // Always true.
    return getTrue(ITy);
  if (Pred == CmpInst::ICMP_SGT)
    // Always false.
    return getFalse(ITy);
} else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
           match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
           (A == C || A == D || B == C || B == D)) {
  // max(x, ?) pred min(x, ?).
  if (Pred == CmpInst::ICMP_UGE)
    // Always true.
    return getTrue(ITy);
  if (Pred == CmpInst::ICMP_ULT)
    // Always false.
    return getFalse(ITy);
} else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
           match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
           (A == C || A == D || B == C || B == D)) {
  // min(x, ?) pred max(x, ?).
  if (Pred == CmpInst::ICMP_ULE)
    // Always true.
    return getTrue(ITy);
  if (Pred == CmpInst::ICMP_UGT)
    // Always false.
    return getFalse(ITy);
}

return nullptr;
3050}

3052/// Given operands for an ICmpInst, see if we can fold the result.
3053/// If not, this returns null.
3054static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
                             const SimplifyQuery &Q, unsigned MaxRecurse) {
CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!")(static_cast <bool> (CmpInst::isIntPredicate(Pred) &&
 "Not an integer compare!") ? void (0) : __assert_fail ("CmpInst::isIntPredicate(Pred) && \"Not an integer compare!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 3057, __extension__ __PRETTY_FUNCTION__));

if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
  if (Constant *CRHS = dyn_cast<Constant>(RHS))
    return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);

  // If we have a constant, make sure it is on the RHS.
  std::swap(LHS, RHS);
  Pred = CmpInst::getSwappedPredicate(Pred);
}

Type *ITy = GetCompareTy(LHS); // The return type.

// icmp X, X -> true/false
// X icmp undef -> true/false.  For example, icmp ugt %X, undef -> false
// because X could be 0.
if (LHS == RHS || isa<UndefValue>(RHS))
  return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));

if (Value *V = simplifyICmpOfBools(Pred, LHS, RHS, Q))
  return V;

if (Value *V = simplifyICmpWithZero(Pred, LHS, RHS, Q))
  return V;

if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS))
  return V;

// If both operands have range metadata, use the metadata
// to simplify the comparison.
if (isa<Instruction>(RHS) && isa<Instruction>(LHS)) {
  auto RHS_Instr = cast<Instruction>(RHS);
  auto LHS_Instr = cast<Instruction>(LHS);

  if (RHS_Instr->getMetadata(LLVMContext::MD_range) &&
      LHS_Instr->getMetadata(LLVMContext::MD_range)) {
    auto RHS_CR = getConstantRangeFromMetadata(
        *RHS_Instr->getMetadata(LLVMContext::MD_range));
    auto LHS_CR = getConstantRangeFromMetadata(
        *LHS_Instr->getMetadata(LLVMContext::MD_range));

    auto Satisfied_CR = ConstantRange::makeSatisfyingICmpRegion(Pred, RHS_CR);
    if (Satisfied_CR.contains(LHS_CR))
      return ConstantInt::getTrue(RHS->getContext());

    auto InversedSatisfied_CR = ConstantRange::makeSatisfyingICmpRegion(
              CmpInst::getInversePredicate(Pred), RHS_CR);
    if (InversedSatisfied_CR.contains(LHS_CR))
      return ConstantInt::getFalse(RHS->getContext());
  }
}

// Compare of cast, for example (zext X) != 0 -> X != 0
if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
  Instruction *LI = cast<CastInst>(LHS);
  Value *SrcOp = LI->getOperand(0);
  Type *SrcTy = SrcOp->getType();
  Type *DstTy = LI->getType();

  // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
  // if the integer type is the same size as the pointer type.
  if (MaxRecurse && isa<PtrToIntInst>(LI) &&
      Q.DL.getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) {
    if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
      // Transfer the cast to the constant.
      if (Value *V = SimplifyICmpInst(Pred, SrcOp,
                                      ConstantExpr::getIntToPtr(RHSC, SrcTy),
                                      Q, MaxRecurse-1))
        return V;
    } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
      if (RI->getOperand(0)->getType() == SrcTy)
        // Compare without the cast.
        if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
                                        Q, MaxRecurse-1))
          return V;
    }
  }

  if (isa<ZExtInst>(LHS)) {
    // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
    // same type.
    if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
      if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
        // Compare X and Y.  Note that signed predicates become unsigned.
        if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
                                        SrcOp, RI->getOperand(0), Q,
                                        MaxRecurse-1))
          return V;
    }
    // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
    // too.  If not, then try to deduce the result of the comparison.
    else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
      // Compute the constant that would happen if we truncated to SrcTy then
      // reextended to DstTy.
      Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
      Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);

      // If the re-extended constant didn't change then this is effectively
      // also a case of comparing two zero-extended values.
      if (RExt == CI && MaxRecurse)
        if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
                                      SrcOp, Trunc, Q, MaxRecurse-1))
          return V;

      // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
      // there.  Use this to work out the result of the comparison.
      if (RExt != CI) {
        switch (Pred) {
        default: llvm_unreachable("Unknown ICmp predicate!")::llvm::llvm_unreachable_internal("Unknown ICmp predicate!", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 3165);
        // LHS <u RHS.
        case ICmpInst::ICMP_EQ:
        case ICmpInst::ICMP_UGT:
        case ICmpInst::ICMP_UGE:
          return ConstantInt::getFalse(CI->getContext());

        case ICmpInst::ICMP_NE:
        case ICmpInst::ICMP_ULT:
        case ICmpInst::ICMP_ULE:
          return ConstantInt::getTrue(CI->getContext());

        // LHS is non-negative.  If RHS is negative then LHS >s LHS.  If RHS
        // is non-negative then LHS <s RHS.
        case ICmpInst::ICMP_SGT:
        case ICmpInst::ICMP_SGE:
          return CI->getValue().isNegative() ?
            ConstantInt::getTrue(CI->getContext()) :
            ConstantInt::getFalse(CI->getContext());

        case ICmpInst::ICMP_SLT:
        case ICmpInst::ICMP_SLE:
          return CI->getValue().isNegative() ?
            ConstantInt::getFalse(CI->getContext()) :
            ConstantInt::getTrue(CI->getContext());
        }
      }
    }
  }

  if (isa<SExtInst>(LHS)) {
    // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
    // same type.
    if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
      if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
        // Compare X and Y.  Note that the predicate does not change.
        if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
                                        Q, MaxRecurse-1))
          return V;
    }
    // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
    // too.  If not, then try to deduce the result of the comparison.
    else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
      // Compute the constant that would happen if we truncated to SrcTy then
      // reextended to DstTy.
      Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
      Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);

      // If the re-extended constant didn't change then this is effectively
      // also a case of comparing two sign-extended values.
      if (RExt == CI && MaxRecurse)
        if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
          return V;

      // Otherwise the upper bits of LHS are all equal, while RHS has varying
      // bits there.  Use this to work out the result of the comparison.
      if (RExt != CI) {
        switch (Pred) {
        default: llvm_unreachable("Unknown ICmp predicate!")::llvm::llvm_unreachable_internal("Unknown ICmp predicate!", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 3223);
        case ICmpInst::ICMP_EQ:
          return ConstantInt::getFalse(CI->getContext());
        case ICmpInst::ICMP_NE:
          return ConstantInt::getTrue(CI->getContext());

        // If RHS is non-negative then LHS <s RHS.  If RHS is negative then
        // LHS >s RHS.
        case ICmpInst::ICMP_SGT:
        case ICmpInst::ICMP_SGE:
          return CI->getValue().isNegative() ?
            ConstantInt::getTrue(CI->getContext()) :
            ConstantInt::getFalse(CI->getContext());
        case ICmpInst::ICMP_SLT:
        case ICmpInst::ICMP_SLE:
          return CI->getValue().isNegative() ?
            ConstantInt::getFalse(CI->getContext()) :
            ConstantInt::getTrue(CI->getContext());

        // If LHS is non-negative then LHS <u RHS.  If LHS is negative then
        // LHS >u RHS.
        case ICmpInst::ICMP_UGT:
        case ICmpInst::ICMP_UGE:
          // Comparison is true iff the LHS <s 0.
          if (MaxRecurse)
            if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
                                            Constant::getNullValue(SrcTy),
                                            Q, MaxRecurse-1))
              return V;
          break;
        case ICmpInst::ICMP_ULT:
        case ICmpInst::ICMP_ULE:
          // Comparison is true iff the LHS >=s 0.
          if (MaxRecurse)
            if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
                                            Constant::getNullValue(SrcTy),
                                            Q, MaxRecurse-1))
              return V;
          break;
        }
      }
    }
  }
}

// icmp eq|ne X, Y -> false|true if X != Y
if (ICmpInst::isEquality(Pred) &&
    isKnownNonEqual(LHS, RHS, Q.DL, Q.AC, Q.CxtI, Q.DT)) {
  return Pred == ICmpInst::ICMP_NE ? getTrue(ITy) : getFalse(ITy);
}

if (Value *V = simplifyICmpWithBinOp(Pred, LHS, RHS, Q, MaxRecurse))
  return V;

if (Value *V = simplifyICmpWithMinMax(Pred, LHS, RHS, Q, MaxRecurse))
  return V;

// Simplify comparisons of related pointers using a powerful, recursive
// GEP-walk when we have target data available..
if (LHS->getType()->isPointerTy())
  if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI, LHS,
                                   RHS))
    return C;
if (auto *CLHS = dyn_cast<PtrToIntOperator>(LHS))
  if (auto *CRHS = dyn_cast<PtrToIntOperator>(RHS))
    if (Q.DL.getTypeSizeInBits(CLHS->getPointerOperandType()) ==
            Q.DL.getTypeSizeInBits(CLHS->getType()) &&
        Q.DL.getTypeSizeInBits(CRHS->getPointerOperandType()) ==
            Q.DL.getTypeSizeInBits(CRHS->getType()))
      if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI,
                                       CLHS->getPointerOperand(),
                                       CRHS->getPointerOperand()))
        return C;

if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
  if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
    if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
        GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
        (ICmpInst::isEquality(Pred) ||
         (GLHS->isInBounds() && GRHS->isInBounds() &&
          Pred == ICmpInst::getSignedPredicate(Pred)))) {
      // The bases are equal and the indices are constant.  Build a constant
      // expression GEP with the same indices and a null base pointer to see
      // what constant folding can make out of it.
      Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
      SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
      Constant *NewLHS = ConstantExpr::getGetElementPtr(
          GLHS->getSourceElementType(), Null, IndicesLHS);

      SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
      Constant *NewRHS = ConstantExpr::getGetElementPtr(
          GLHS->getSourceElementType(), Null, IndicesRHS);
      return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
    }
  }
}

// If the comparison is with the result of a select instruction, check whether
// comparing with either branch of the select always yields the same value.
if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
    return V;

// If the comparison is with the result of a phi instruction, check whether
// doing the compare with each incoming phi value yields a common result.
if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
    return V;

return nullptr;
3333}

3335Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
                            const SimplifyQuery &Q) {
return ::SimplifyICmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
3338}

3340/// Given operands for an FCmpInst, see if we can fold the result.
3341/// If not, this returns null.
3342static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
                             FastMathFlags FMF, const SimplifyQuery &Q,
                             unsigned MaxRecurse) {
CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!")(static_cast <bool> (CmpInst::isFPPredicate(Pred) &&
 "Not an FP compare!") ? void (0) : __assert_fail ("CmpInst::isFPPredicate(Pred) && \"Not an FP compare!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 3346, __extension__ __PRETTY_FUNCTION__));

if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
  if (Constant *CRHS = dyn_cast<Constant>(RHS))
    return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI);

  // If we have a constant, make sure it is on the RHS.
  std::swap(LHS, RHS);
  Pred = CmpInst::getSwappedPredicate(Pred);
}

// Fold trivial predicates.
Type *RetTy = GetCompareTy(LHS);
if (Pred == FCmpInst::FCMP_FALSE)
  return getFalse(RetTy);
if (Pred == FCmpInst::FCMP_TRUE)
  return getTrue(RetTy);

// UNO/ORD predicates can be trivially folded if NaNs are ignored.
if (FMF.noNaNs()) {
  if (Pred == FCmpInst::FCMP_UNO)
    return getFalse(RetTy);
  if (Pred == FCmpInst::FCMP_ORD)
    return getTrue(RetTy);
}

// NaN is unordered; NaN is not ordered.
assert((FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) &&(static_cast <bool> ((FCmpInst::isOrdered(Pred) || FCmpInst
::isUnordered(Pred)) && "Comparison must be either ordered or unordered"
) ? void (0) : __assert_fail ("(FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) && \"Comparison must be either ordered or unordered\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 3374, __extension__ __PRETTY_FUNCTION__))
       "Comparison must be either ordered or unordered")(static_cast <bool> ((FCmpInst::isOrdered(Pred) || FCmpInst
::isUnordered(Pred)) && "Comparison must be either ordered or unordered"
) ? void (0) : __assert_fail ("(FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) && \"Comparison must be either ordered or unordered\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 3374, __extension__ __PRETTY_FUNCTION__));
if (match(RHS, m_NaN()))
  return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));

// fcmp pred x, undef  and  fcmp pred undef, x
// fold to true if unordered, false if ordered
if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) {
  // Choosing NaN for the undef will always make unordered comparison succeed
  // and ordered comparison fail.
  return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
}

// fcmp x,x -> true/false.  Not all compares are foldable.
if (LHS == RHS) {
  if (CmpInst::isTrueWhenEqual(Pred))
    return getTrue(RetTy);
  if (CmpInst::isFalseWhenEqual(Pred))
    return getFalse(RetTy);
}

// Handle fcmp with constant RHS.
const APFloat *C;
if (match(RHS, m_APFloat(C))) {
  // Check whether the constant is an infinity.
  if (C->isInfinity()) {
    if (C->isNegative()) {
      switch (Pred) {
      case FCmpInst::FCMP_OLT:
        // No value is ordered and less than negative infinity.
        return getFalse(RetTy);
      case FCmpInst::FCMP_UGE:
        // All values are unordered with or at least negative infinity.
        return getTrue(RetTy);
      default:
        break;
      }
    } else {
      switch (Pred) {
      case FCmpInst::FCMP_OGT:
        // No value is ordered and greater than infinity.
        return getFalse(RetTy);
      case FCmpInst::FCMP_ULE:
        // All values are unordered with and at most infinity.
        return getTrue(RetTy);
      default:
        break;
      }
    }
  }
  if (C->isZero()) {
    switch (Pred) {
    case FCmpInst::FCMP_UGE:
      if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
        return getTrue(RetTy);
      break;
    case FCmpInst::FCMP_OLT:
      // X < 0
      if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
        return getFalse(RetTy);
      break;
    default:
      break;
    }
  } else if (C->isNegative()) {
    assert(!C->isNaN() && "Unexpected NaN constant!")(static_cast <bool> (!C->isNaN() && "Unexpected NaN constant!"
) ? void (0) : __assert_fail ("!C->isNaN() && \"Unexpected NaN constant!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 3438, __extension__ __PRETTY_FUNCTION__));
    // TODO: We can catch more cases by using a range check rather than
    //       relying on CannotBeOrderedLessThanZero.
    switch (Pred) {
    case FCmpInst::FCMP_UGE:
    case FCmpInst::FCMP_UGT:
    case FCmpInst::FCMP_UNE:
      // (X >= 0) implies (X > C) when (C < 0)
      if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
        return getTrue(RetTy);
      break;
    case FCmpInst::FCMP_OEQ:
    case FCmpInst::FCMP_OLE:
    case FCmpInst::FCMP_OLT:
      // (X >= 0) implies !(X < C) when (C < 0)
      if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
        return getFalse(RetTy);
      break;
    default:
      break;
    }
  }
}

// If the comparison is with the result of a select instruction, check whether
// comparing with either branch of the select always yields the same value.
if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
  if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
    return V;

// If the comparison is with the result of a phi instruction, check whether
// doing the compare with each incoming phi value yields a common result.
if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
  if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
    return V;

return nullptr;
3475}

3477Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
                            FastMathFlags FMF, const SimplifyQuery &Q) {
return ::SimplifyFCmpInst(Predicate, LHS, RHS, FMF, Q, RecursionLimit);
3480}

3482/// See if V simplifies when its operand Op is replaced with RepOp.
3483static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
                                         const SimplifyQuery &Q,
                                         unsigned MaxRecurse) {
// Trivial replacement.
if (V == Op)
  return RepOp;

// We cannot replace a constant, and shouldn't even try.
if (isa<Constant>(Op))
  return nullptr;

auto *I = dyn_cast<Instruction>(V);
if (!I)
  return nullptr;

// If this is a binary operator, try to simplify it with the replaced op.
if (auto *B = dyn_cast<BinaryOperator>(I)) {
  // Consider:
  //   %cmp = icmp eq i32 %x, 2147483647
  //   %add = add nsw i32 %x, 1
  //   %sel = select i1 %cmp, i32 -2147483648, i32 %add
  //
  // We can't replace %sel with %add unless we strip away the flags.
  if (isa<OverflowingBinaryOperator>(B))
    if (B->hasNoSignedWrap() || B->hasNoUnsignedWrap())
      return nullptr;
  if (isa<PossiblyExactOperator>(B))
    if (B->isExact())
      return nullptr;

  if (MaxRecurse) {
    if (B->getOperand(0) == Op)
      return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), Q,
                           MaxRecurse - 1);
    if (B->getOperand(1) == Op)
      return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, Q,
                           MaxRecurse - 1);
  }
}

// Same for CmpInsts.
if (CmpInst *C = dyn_cast<CmpInst>(I)) {
  if (MaxRecurse) {
    if (C->getOperand(0) == Op)
      return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), Q,
                             MaxRecurse - 1);
    if (C->getOperand(1) == Op)
      return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, Q,
                             MaxRecurse - 1);
  }
}

// TODO: We could hand off more cases to instsimplify here.

// If all operands are constant after substituting Op for RepOp then we can
// constant fold the instruction.
if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) {
  // Build a list of all constant operands.
  SmallVector<Constant *, 8> ConstOps;
  for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
    if (I->getOperand(i) == Op)
      ConstOps.push_back(CRepOp);
    else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i)))
      ConstOps.push_back(COp);
    else
      break;
  }

  // All operands were constants, fold it.
  if (ConstOps.size() == I->getNumOperands()) {
    if (CmpInst *C = dyn_cast<CmpInst>(I))
      return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0],
                                             ConstOps[1], Q.DL, Q.TLI);

    if (LoadInst *LI = dyn_cast<LoadInst>(I))
      if (!LI->isVolatile())
        return ConstantFoldLoadFromConstPtr(ConstOps[0], LI->getType(), Q.DL);

    return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
  }
}

return nullptr;
3566}

3568/// Try to simplify a select instruction when its condition operand is an
3569/// integer comparison where one operand of the compare is a constant.
3570static Value *simplifySelectBitTest(Value *TrueVal, Value *FalseVal, Value *X,
                                  const APInt *Y, bool TrueWhenUnset) {
const APInt *C;

// (X & Y) == 0 ? X & ~Y : X  --> X
// (X & Y) != 0 ? X & ~Y : X  --> X & ~Y
if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
    *Y == ~*C)
  return TrueWhenUnset ? FalseVal : TrueVal;

// (X & Y) == 0 ? X : X & ~Y  --> X & ~Y
// (X & Y) != 0 ? X : X & ~Y  --> X
if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
    *Y == ~*C)
  return TrueWhenUnset ? FalseVal : TrueVal;

if (Y->isPowerOf2()) {
  // (X & Y) == 0 ? X | Y : X  --> X | Y
  // (X & Y) != 0 ? X | Y : X  --> X
  if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
      *Y == *C)
    return TrueWhenUnset ? TrueVal : FalseVal;

  // (X & Y) == 0 ? X : X | Y  --> X
  // (X & Y) != 0 ? X : X | Y  --> X | Y
  if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
      *Y == *C)
    return TrueWhenUnset ? TrueVal : FalseVal;
}

return nullptr;
3601}

3603/// An alternative way to test if a bit is set or not uses sgt/slt instead of
3604/// eq/ne.
3605static Value *simplifySelectWithFakeICmpEq(Value *CmpLHS, Value *CmpRHS,
                                         ICmpInst::Predicate Pred,
                                         Value *TrueVal, Value *FalseVal) {
Value *X;
APInt Mask;
if (!decomposeBitTestICmp(CmpLHS, CmpRHS, Pred, X, Mask))
  return nullptr;

return simplifySelectBitTest(TrueVal, FalseVal, X, &Mask,
                             Pred == ICmpInst::ICMP_EQ);
3615}

3617/// Try to simplify a select instruction when its condition operand is an
3618/// integer comparison.
3619static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
                                       Value *FalseVal, const SimplifyQuery &Q,
                                       unsigned MaxRecurse) {
ICmpInst::Predicate Pred;
Value *CmpLHS, *CmpRHS;
if (!match(CondVal, m_ICmp(Pred, m_Value(CmpLHS), m_Value(CmpRHS))))
  return nullptr;

if (ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero())) {
  Value *X;
  const APInt *Y;
  if (match(CmpLHS, m_And(m_Value(X), m_APInt(Y))))
    if (Value *V = simplifySelectBitTest(TrueVal, FalseVal, X, Y,
                                         Pred == ICmpInst::ICMP_EQ))
      return V;
}

// Check for other compares that behave like bit test.
if (Value *V = simplifySelectWithFakeICmpEq(CmpLHS, CmpRHS, Pred,
                                            TrueVal, FalseVal))
  return V;

// If we have an equality comparison, then we know the value in one of the
// arms of the select. See if substituting this value into the arm and
// simplifying the result yields the same value as the other arm.
if (Pred == ICmpInst::ICMP_EQ) {
  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
          TrueVal ||
      SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
          TrueVal)
    return FalseVal;
  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
          FalseVal ||
      SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
          FalseVal)
    return FalseVal;
} else if (Pred == ICmpInst::ICMP_NE) {
  if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
          FalseVal ||
      SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
          FalseVal)
    return TrueVal;
  if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) ==
          TrueVal ||
      SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) ==
          TrueVal)
    return TrueVal;
}

return nullptr;
3669}

3671/// Given operands for a SelectInst, see if we can fold the result.
3672/// If not, this returns null.
3673static Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
                               const SimplifyQuery &Q, unsigned MaxRecurse) {
if (auto *CondC = dyn_cast<Constant>(Cond)) {
  if (auto *TrueC = dyn_cast<Constant>(TrueVal))
    if (auto *FalseC = dyn_cast<Constant>(FalseVal))
      return ConstantFoldSelectInstruction(CondC, TrueC, FalseC);

  // select undef, X, Y -> X or Y
  if (isa<UndefValue>(CondC))
    return isa<Constant>(FalseVal) ? FalseVal : TrueVal;

  // TODO: Vector constants with undef elements don't simplify.

  // select true, X, Y  -> X
  if (CondC->isAllOnesValue())
    return TrueVal;
  // select false, X, Y -> Y
  if (CondC->isNullValue())
    return FalseVal;
}

// select ?, X, X -> X
if (TrueVal == FalseVal)
  return TrueVal;

if (isa<UndefValue>(TrueVal))   // select ?, undef, X -> X
  return FalseVal;
if (isa<UndefValue>(FalseVal))   // select ?, X, undef -> X
  return TrueVal;

if (Value *V =
        simplifySelectWithICmpCond(Cond, TrueVal, FalseVal, Q, MaxRecurse))
  return V;

return nullptr;
3708}

3710Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
                              const SimplifyQuery &Q) {
return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Q, RecursionLimit);
3713}

3715/// Given operands for an GetElementPtrInst, see if we can fold the result.
3716/// If not, this returns null.
3717static Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
                            const SimplifyQuery &Q, unsigned) {
// The type of the GEP pointer operand.
unsigned AS =
    cast<PointerType>(Ops[0]->getType()->getScalarType())->getAddressSpace();

// getelementptr P -> P.
if (Ops.size() == 1)
  return Ops[0];

// Compute the (pointer) type returned by the GEP instruction.
Type *LastType = GetElementPtrInst::getIndexedType(SrcTy, Ops.slice(1));
Type *GEPTy = PointerType::get(LastType, AS);
if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
  GEPTy = VectorType::get(GEPTy, VT->getNumElements());
else if (VectorType *VT = dyn_cast<VectorType>(Ops[1]->getType()))
  GEPTy = VectorType::get(GEPTy, VT->getNumElements());

if (isa<UndefValue>(Ops[0]))
  return UndefValue::get(GEPTy);

if (Ops.size() == 2) {
  // getelementptr P, 0 -> P.
  if (match(Ops[1], m_Zero()) && Ops[0]->getType() == GEPTy)
    return Ops[0];

  Type *Ty = SrcTy;
  if (Ty->isSized()) {
    Value *P;
    uint64_t C;
    uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
    // getelementptr P, N -> P if P points to a type of zero size.
    if (TyAllocSize == 0 && Ops[0]->getType() == GEPTy)
      return Ops[0];

    // The following transforms are only safe if the ptrtoint cast
    // doesn't truncate the pointers.
    if (Ops[1]->getType()->getScalarSizeInBits() ==
        Q.DL.getIndexSizeInBits(AS)) {
      auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
        if (match(P, m_Zero()))
          return Constant::getNullValue(GEPTy);
        Value *Temp;
        if (match(P, m_PtrToInt(m_Value(Temp))))
          if (Temp->getType() == GEPTy)
            return Temp;
        return nullptr;
      };

      // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
      if (TyAllocSize == 1 &&
          match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
        if (Value *R = PtrToIntOrZero(P))
          return R;

      // getelementptr V, (ashr (sub P, V), C) -> Q
      // if P points to a type of size 1 << C.
      if (match(Ops[1],
                m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
                       m_ConstantInt(C))) &&
          TyAllocSize == 1ULL << C)
        if (Value *R = PtrToIntOrZero(P))
          return R;

      // getelementptr V, (sdiv (sub P, V), C) -> Q
      // if P points to a type of size C.
      if (match(Ops[1],
                m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
                       m_SpecificInt(TyAllocSize))))
        if (Value *R = PtrToIntOrZero(P))
          return R;
    }
  }
}

if (Q.DL.getTypeAllocSize(LastType) == 1 &&
    all_of(Ops.slice(1).drop_back(1),
           [](Value *Idx) { return match(Idx, m_Zero()); })) {
  unsigned IdxWidth =
      Q.DL.getIndexSizeInBits(Ops[0]->getType()->getPointerAddressSpace());
  if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == IdxWidth) {
    APInt BasePtrOffset(IdxWidth, 0);
    Value *StrippedBasePtr =
        Ops[0]->stripAndAccumulateInBoundsConstantOffsets(Q.DL,
                                                          BasePtrOffset);

    // gep (gep V, C), (sub 0, V) -> C
    if (match(Ops.back(),
              m_Sub(m_Zero(), m_PtrToInt(m_Specific(StrippedBasePtr))))) {
      auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset);
      return ConstantExpr::getIntToPtr(CI, GEPTy);
    }
    // gep (gep V, C), (xor V, -1) -> C-1
    if (match(Ops.back(),
              m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr)), m_AllOnes()))) {
      auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset - 1);
      return ConstantExpr::getIntToPtr(CI, GEPTy);
    }
  }
}

// Check to see if this is constant foldable.
if (!all_of(Ops, [](Value *V) { return isa<Constant>(V); }))
  return nullptr;

auto *CE = ConstantExpr::getGetElementPtr(SrcTy, cast<Constant>(Ops[0]),
                                          Ops.slice(1));
if (auto *CEFolded = ConstantFoldConstant(CE, Q.DL))
  return CEFolded;
return CE;
3827}

3829Value *llvm::SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
                           const SimplifyQuery &Q) {
return ::SimplifyGEPInst(SrcTy, Ops, Q, RecursionLimit);
3832}

3834/// Given operands for an InsertValueInst, see if we can fold the result.
3835/// If not, this returns null.
3836static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
                                    ArrayRef<unsigned> Idxs, const SimplifyQuery &Q,
                                    unsigned) {
if (Constant *CAgg = dyn_cast<Constant>(Agg))
  if (Constant *CVal = dyn_cast<Constant>(Val))
    return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);

// insertvalue x, undef, n -> x
if (match(Val, m_Undef()))
  return Agg;

// insertvalue x, (extractvalue y, n), n
if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
  if (EV->getAggregateOperand()->getType() == Agg->getType() &&
      EV->getIndices() == Idxs) {
    // insertvalue undef, (extractvalue y, n), n -> y
    if (match(Agg, m_Undef()))
      return EV->getAggregateOperand();

    // insertvalue y, (extractvalue y, n), n -> y
    if (Agg == EV->getAggregateOperand())
      return Agg;
  }

return nullptr;
3861}

3863Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
                                   ArrayRef<unsigned> Idxs,
                                   const SimplifyQuery &Q) {
return ::SimplifyInsertValueInst(Agg, Val, Idxs, Q, RecursionLimit);
3867}

3869Value *llvm::SimplifyInsertElementInst(Value *Vec, Value *Val, Value *Idx,
                                     const SimplifyQuery &Q) {
// Try to constant fold.
auto *VecC = dyn_cast<Constant>(Vec);
auto *ValC = dyn_cast<Constant>(Val);
auto *IdxC = dyn_cast<Constant>(Idx);
if (VecC && ValC && IdxC)
  return ConstantFoldInsertElementInstruction(VecC, ValC, IdxC);

// Fold into undef if index is out of bounds.
if (auto *CI = dyn_cast<ConstantInt>(Idx)) {
  uint64_t NumElements = cast<VectorType>(Vec->getType())->getNumElements();
  if (CI->uge(NumElements))
    return UndefValue::get(Vec->getType());
}

// If index is undef, it might be out of bounds (see above case)
if (isa<UndefValue>(Idx))
  return UndefValue::get(Vec->getType());

return nullptr;
3890}

3892/// Given operands for an ExtractValueInst, see if we can fold the result.
3893/// If not, this returns null.
3894static Value *SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
                                     const SimplifyQuery &, unsigned) {
if (auto *CAgg = dyn_cast<Constant>(Agg))
  return ConstantFoldExtractValueInstruction(CAgg, Idxs);

// extractvalue x, (insertvalue y, elt, n), n -> elt
unsigned NumIdxs = Idxs.size();
for (auto *IVI = dyn_cast<InsertValueInst>(Agg); IVI != nullptr;
     IVI = dyn_cast<InsertValueInst>(IVI->getAggregateOperand())) {
  ArrayRef<unsigned> InsertValueIdxs = IVI->getIndices();
  unsigned NumInsertValueIdxs = InsertValueIdxs.size();
  unsigned NumCommonIdxs = std::min(NumInsertValueIdxs, NumIdxs);
  if (InsertValueIdxs.slice(0, NumCommonIdxs) ==
      Idxs.slice(0, NumCommonIdxs)) {
    if (NumIdxs == NumInsertValueIdxs)
      return IVI->getInsertedValueOperand();
    break;
  }
}

return nullptr;
3915}

3917Value *llvm::SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
                                    const SimplifyQuery &Q) {
return ::SimplifyExtractValueInst(Agg, Idxs, Q, RecursionLimit);
3920}

3922/// Given operands for an ExtractElementInst, see if we can fold the result.
3923/// If not, this returns null.
3924static Value *SimplifyExtractElementInst(Value *Vec, Value *Idx, const SimplifyQuery &,
                                       unsigned) {
if (auto *CVec = dyn_cast<Constant>(Vec)) {
  if (auto *CIdx = dyn_cast<Constant>(Idx))
    return ConstantFoldExtractElementInstruction(CVec, CIdx);

  // The index is not relevant if our vector is a splat.
  if (auto *Splat = CVec->getSplatValue())
    return Splat;

  if (isa<UndefValue>(Vec))
    return UndefValue::get(Vec->getType()->getVectorElementType());
}

// If extracting a specified index from the vector, see if we can recursively
// find a previously computed scalar that was inserted into the vector.
if (auto *IdxC = dyn_cast<ConstantInt>(Idx)) {
  if (IdxC->getValue().uge(Vec->getType()->getVectorNumElements()))
    // definitely out of bounds, thus undefined result
    return UndefValue::get(Vec->getType()->getVectorElementType());
  if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
    return Elt;
}

// An undef extract index can be arbitrarily chosen to be an out-of-range
// index value, which would result in the instruction being undef.
if (isa<UndefValue>(Idx))
  return UndefValue::get(Vec->getType()->getVectorElementType());

return nullptr;
3954}

3956Value *llvm::SimplifyExtractElementInst(Value *Vec, Value *Idx,
                                      const SimplifyQuery &Q) {
return ::SimplifyExtractElementInst(Vec, Idx, Q, RecursionLimit);
3959}

3961/// See if we can fold the given phi. If not, returns null.
3962static Value *SimplifyPHINode(PHINode *PN, const SimplifyQuery &Q) {
// If all of the PHI's incoming values are the same then replace the PHI node
// with the common value.
Value *CommonValue = nullptr;
bool HasUndefInput = false;
for (Value *Incoming : PN->incoming_values()) {
  // If the incoming value is the phi node itself, it can safely be skipped.
  if (Incoming == PN) continue;
  if (isa<UndefValue>(Incoming)) {
    // Remember that we saw an undef value, but otherwise ignore them.
    HasUndefInput = true;
    continue;
  }
  if (CommonValue && Incoming != CommonValue)
    return nullptr;  // Not the same, bail out.
  CommonValue = Incoming;
}

// If CommonValue is null then all of the incoming values were either undef or
// equal to the phi node itself.
if (!CommonValue)
  return UndefValue::get(PN->getType());

// If we have a PHI node like phi(X, undef, X), where X is defined by some
// instruction, we cannot return X as the result of the PHI node unless it
// dominates the PHI block.
if (HasUndefInput)
  return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;

return CommonValue;
3992}

3994static Value *SimplifyCastInst(unsigned CastOpc, Value *Op,
                             Type *Ty, const SimplifyQuery &Q, unsigned MaxRecurse) {
if (auto *C = dyn_cast<Constant>(Op))
  return ConstantFoldCastOperand(CastOpc, C, Ty, Q.DL);

if (auto *CI = dyn_cast<CastInst>(Op)) {
  auto *Src = CI->getOperand(0);
  Type *SrcTy = Src->getType();
  Type *MidTy = CI->getType();
  Type *DstTy = Ty;
  if (Src->getType() == Ty) {
    auto FirstOp = static_cast<Instruction::CastOps>(CI->getOpcode());
    auto SecondOp = static_cast<Instruction::CastOps>(CastOpc);
    Type *SrcIntPtrTy =
        SrcTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(SrcTy) : nullptr;
    Type *MidIntPtrTy =
        MidTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(MidTy) : nullptr;
    Type *DstIntPtrTy =
        DstTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(DstTy) : nullptr;
    if (CastInst::isEliminableCastPair(FirstOp, SecondOp, SrcTy, MidTy, DstTy,
                                       SrcIntPtrTy, MidIntPtrTy,
                                       DstIntPtrTy) == Instruction::BitCast)
      return Src;
  }
}

// bitcast x -> x
if (CastOpc == Instruction::BitCast)
  if (Op->getType() == Ty)
    return Op;

return nullptr;
4026}

4028Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty,
                            const SimplifyQuery &Q) {
return ::SimplifyCastInst(CastOpc, Op, Ty, Q, RecursionLimit);
4031}

4033/// For the given destination element of a shuffle, peek through shuffles to
4034/// match a root vector source operand that contains that element in the same
4035/// vector lane (ie, the same mask index), so we can eliminate the shuffle(s).
4036static Value *foldIdentityShuffles(int DestElt, Value *Op0, Value *Op1,
                                 int MaskVal, Value *RootVec,
                                 unsigned MaxRecurse) {
if (!MaxRecurse--)
  return nullptr;

// Bail out if any mask value is undefined. That kind of shuffle may be
// simplified further based on demanded bits or other folds.
if (MaskVal == -1)
  return nullptr;

// The mask value chooses which source operand we need to look at next.
int InVecNumElts = Op0->getType()->getVectorNumElements();
int RootElt = MaskVal;
Value *SourceOp = Op0;
if (MaskVal >= InVecNumElts) {
  RootElt = MaskVal - InVecNumElts;
  SourceOp = Op1;
}

// If the source operand is a shuffle itself, look through it to find the
// matching root vector.
if (auto *SourceShuf = dyn_cast<ShuffleVectorInst>(SourceOp)) {
  return foldIdentityShuffles(
      DestElt, SourceShuf->getOperand(0), SourceShuf->getOperand(1),
      SourceShuf->getMaskValue(RootElt), RootVec, MaxRecurse);
}

// TODO: Look through bitcasts? What if the bitcast changes the vector element
// size?

// The source operand is not a shuffle. Initialize the root vector value for
// this shuffle if that has not been done yet.
if (!RootVec)
  RootVec = SourceOp;

// Give up as soon as a source operand does not match the existing root value.
if (RootVec != SourceOp)
  return nullptr;

// The element must be coming from the same lane in the source vector
// (although it may have crossed lanes in intermediate shuffles).
if (RootElt != DestElt)
  return nullptr;

return RootVec;
4082}

4084static Value *SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask,
                                      Type *RetTy, const SimplifyQuery &Q,
                                      unsigned MaxRecurse) {
if (isa<UndefValue>(Mask))
  return UndefValue::get(RetTy);

Type *InVecTy = Op0->getType();
unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
unsigned InVecNumElts = InVecTy->getVectorNumElements();

SmallVector<int, 32> Indices;
ShuffleVectorInst::getShuffleMask(Mask, Indices);
assert(MaskNumElts == Indices.size() &&(static_cast <bool> (MaskNumElts == Indices.size() &&
 "Size of Indices not same as number of mask elements?") ? void
 (0) : __assert_fail ("MaskNumElts == Indices.size() && \"Size of Indices not same as number of mask elements?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 4097, __extension__ __PRETTY_FUNCTION__))
       "Size of Indices not same as number of mask elements?")(static_cast <bool> (MaskNumElts == Indices.size() &&
 "Size of Indices not same as number of mask elements?") ? void
 (0) : __assert_fail ("MaskNumElts == Indices.size() && \"Size of Indices not same as number of mask elements?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 4097, __extension__ __PRETTY_FUNCTION__));

// Canonicalization: If mask does not select elements from an input vector,
// replace that input vector with undef.
bool MaskSelects0 = false, MaskSelects1 = false;
for (unsigned i = 0; i != MaskNumElts; ++i) {
  if (Indices[i] == -1)
    continue;
  if ((unsigned)Indices[i] < InVecNumElts)
    MaskSelects0 = true;
  else
    MaskSelects1 = true;
}
if (!MaskSelects0)
  Op0 = UndefValue::get(InVecTy);
if (!MaskSelects1)
  Op1 = UndefValue::get(InVecTy);

auto *Op0Const = dyn_cast<Constant>(Op0);
auto *Op1Const = dyn_cast<Constant>(Op1);

// If all operands are constant, constant fold the shuffle.
if (Op0Const && Op1Const)
  return ConstantFoldShuffleVectorInstruction(Op0Const, Op1Const, Mask);

// Canonicalization: if only one input vector is constant, it shall be the
// second one.
if (Op0Const && !Op1Const) {
  std::swap(Op0, Op1);
  ShuffleVectorInst::commuteShuffleMask(Indices, InVecNumElts);
}

// A shuffle of a splat is always the splat itself. Legal if the shuffle's
// value type is same as the input vectors' type.
if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0))
  if (isa<UndefValue>(Op1) && RetTy == InVecTy &&
      OpShuf->getMask()->getSplatValue())
    return Op0;

// Don't fold a shuffle with undef mask elements. This may get folded in a
// better way using demanded bits or other analysis.
// TODO: Should we allow this?
if (find(Indices, -1) != Indices.end())
  return nullptr;

// Check if every element of this shuffle can be mapped back to the
// corresponding element of a single root vector. If so, we don't need this
// shuffle. This handles simple identity shuffles as well as chains of
// shuffles that may widen/narrow and/or move elements across lanes and back.
Value *RootVec = nullptr;
for (unsigned i = 0; i != MaskNumElts; ++i) {
  // Note that recursion is limited for each vector element, so if any element
  // exceeds the limit, this will fail to simplify.
  RootVec =
      foldIdentityShuffles(i, Op0, Op1, Indices[i], RootVec, MaxRecurse);

  // We can't replace a widening/narrowing shuffle with one of its operands.
  if (!RootVec || RootVec->getType() != RetTy)
    return nullptr;
}
return RootVec;
4158}

4160/// Given operands for a ShuffleVectorInst, fold the result or return null.
4161Value *llvm::SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask,
                                     Type *RetTy, const SimplifyQuery &Q) {
return ::SimplifyShuffleVectorInst(Op0, Op1, Mask, RetTy, Q, RecursionLimit);
4164}

4166static Constant *propagateNaN(Constant *In) {
// If the input is a vector with undef elements, just return a default NaN.
if (!In->isNaN())
  return ConstantFP::getNaN(In->getType());

// Propagate the existing NaN constant when possible.
// TODO: Should we quiet a signaling NaN?
return In;
4174}

4176static Constant *simplifyFPBinop(Value *Op0, Value *Op1) {
if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
  return ConstantFP::getNaN(Op0->getType());

if (match(Op0, m_NaN()))
  return propagateNaN(cast<Constant>(Op0));
if (match(Op1, m_NaN()))
  return propagateNaN(cast<Constant>(Op1));

return nullptr;
4186}

4188/// Given operands for an FAdd, see if we can fold the result.  If not, this
4189/// returns null.
4190static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                             const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q))
  return C;

if (Constant *C = simplifyFPBinop(Op0, Op1))
  return C;

// fadd X, -0 ==> X
if (match(Op1, m_NegZeroFP()))
  return Op0;

// fadd X, 0 ==> X, when we know X is not -0
if (match(Op1, m_PosZeroFP()) &&
    (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
  return Op0;

// With nnan: (+/-0.0 - X) + X --> 0.0 (and commuted variant)
// We don't have to explicitly exclude infinities (ninf): INF + -INF == NaN.
// Negative zeros are allowed because we always end up with positive zero:
// X = -0.0: (-0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
// X = -0.0: ( 0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
// X =  0.0: (-0.0 - ( 0.0)) + ( 0.0) == (-0.0) + ( 0.0) == 0.0
// X =  0.0: ( 0.0 - ( 0.0)) + ( 0.0) == ( 0.0) + ( 0.0) == 0.0
if (FMF.noNaNs() && (match(Op0, m_FSub(m_AnyZeroFP(), m_Specific(Op1))) ||
                     match(Op1, m_FSub(m_AnyZeroFP(), m_Specific(Op0)))))
  return ConstantFP::getNullValue(Op0->getType());

return nullptr;
4219}

4221/// Given operands for an FSub, see if we can fold the result.  If not, this
4222/// returns null.
4223static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                             const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q))
  return C;

if (Constant *C = simplifyFPBinop(Op0, Op1))
  return C;

// fsub X, +0 ==> X
if (match(Op1, m_PosZeroFP()))
  return Op0;

// fsub X, -0 ==> X, when we know X is not -0
if (match(Op1, m_NegZeroFP()) &&
    (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
  return Op0;

// fsub -0.0, (fsub -0.0, X) ==> X
Value *X;
if (match(Op0, m_NegZeroFP()) &&
    match(Op1, m_FSub(m_NegZeroFP(), m_Value(X))))
  return X;

// fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
if (FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()) &&
    match(Op1, m_FSub(m_AnyZeroFP(), m_Value(X))))
  return X;

// fsub nnan x, x ==> 0.0
if (FMF.noNaNs() && Op0 == Op1)
  return Constant::getNullValue(Op0->getType());

return nullptr;
4256}

4258/// Given the operands for an FMul, see if we can fold the result
4259static Value *SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                             const SimplifyQuery &Q, unsigned MaxRecurse) {
if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q))
  return C;

if (Constant *C = simplifyFPBinop(Op0, Op1))
  return C;

// fmul X, 1.0 ==> X
if (match(Op1, m_FPOne()))
  return Op0;

// fmul nnan nsz X, 0 ==> 0
if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZeroFP()))
  return ConstantFP::getNullValue(Op0->getType());

// sqrt(X) * sqrt(X) --> X, if we can:
// 1. Remove the intermediate rounding (reassociate).
// 2. Ignore non-zero negative numbers because sqrt would produce NAN.
// 3. Ignore -0.0 because sqrt(-0.0) == -0.0, but -0.0 * -0.0 == 0.0.
Value *X;
if (Op0 == Op1 && match(Op0, m_Intrinsic<Intrinsic::sqrt>(m_Value(X))) &&
    FMF.allowReassoc() && FMF.noNaNs() && FMF.noSignedZeros())
  return X;

return nullptr;
4285}

4287Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                            const SimplifyQuery &Q) {
return ::SimplifyFAddInst(Op0, Op1, FMF, Q, RecursionLimit);
4290}


4293Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                            const SimplifyQuery &Q) {
return ::SimplifyFSubInst(Op0, Op1, FMF, Q, RecursionLimit);
4296}

4298Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                            const SimplifyQuery &Q) {
return ::SimplifyFMulInst(Op0, Op1, FMF, Q, RecursionLimit);
4301}

4303static Value *SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                             const SimplifyQuery &Q, unsigned) {
if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q))
  return C;

if (Constant *C = simplifyFPBinop(Op0, Op1))
  return C;

// X / 1.0 -> X
if (match(Op1, m_FPOne()))
  return Op0;

// 0 / X -> 0
// Requires that NaNs are off (X could be zero) and signed zeroes are
// ignored (X could be positive or negative, so the output sign is unknown).
if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()))
  return ConstantFP::getNullValue(Op0->getType());

if (FMF.noNaNs()) {
  // X / X -> 1.0 is legal when NaNs are ignored.
  // We can ignore infinities because INF/INF is NaN.
  if (Op0 == Op1)
    return ConstantFP::get(Op0->getType(), 1.0);

  // (X * Y) / Y --> X if we can reassociate to the above form.
  Value *X;
  if (FMF.allowReassoc() && match(Op0, m_c_FMul(m_Value(X), m_Specific(Op1))))
    return X;

  // -X /  X -> -1.0 and
  //  X / -X -> -1.0 are legal when NaNs are ignored.
  // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
  if ((BinaryOperator::isFNeg(Op0, /*IgnoreZeroSign=*/true) &&
       BinaryOperator::getFNegArgument(Op0) == Op1) ||
      (BinaryOperator::isFNeg(Op1, /*IgnoreZeroSign=*/true) &&
       BinaryOperator::getFNegArgument(Op1) == Op0))
    return ConstantFP::get(Op0->getType(), -1.0);
}

return nullptr;
4343}

4345Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                            const SimplifyQuery &Q) {
return ::SimplifyFDivInst(Op0, Op1, FMF, Q, RecursionLimit);
4348}

4350static Value *SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                             const SimplifyQuery &Q, unsigned) {
if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q))
  return C;

if (Constant *C = simplifyFPBinop(Op0, Op1))
  return C;

// Unlike fdiv, the result of frem always matches the sign of the dividend.
// The constant match may include undef elements in a vector, so return a full
// zero constant as the result.
if (FMF.noNaNs()) {
  // +0 % X -> 0
  if (match(Op0, m_PosZeroFP()))
    return ConstantFP::getNullValue(Op0->getType());
  // -0 % X -> -0
  if (match(Op0, m_NegZeroFP()))
    return ConstantFP::getNegativeZero(Op0->getType());
}

return nullptr;
4371}

4373Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                            const SimplifyQuery &Q) {
return ::SimplifyFRemInst(Op0, Op1, FMF, Q, RecursionLimit);
4376}

4378//=== Helper functions for higher up the class hierarchy.

4380/// Given operands for a BinaryOperator, see if we can fold the result.
4381/// If not, this returns null.
4382static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
                          const SimplifyQuery &Q, unsigned MaxRecurse) {
switch (Opcode) {
2
←
Control jumps to 'case AShr:'  at line 4403→
case Instruction::Add:
  return SimplifyAddInst(LHS, RHS, false, false, Q, MaxRecurse);
case Instruction::Sub:
  return SimplifySubInst(LHS, RHS, false, false, Q, MaxRecurse);
case Instruction::Mul:
  return SimplifyMulInst(LHS, RHS, Q, MaxRecurse);
case Instruction::SDiv:
  return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
case Instruction::UDiv:
  return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
case Instruction::SRem:
  return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
case Instruction::URem:
  return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
case Instruction::Shl:
  return SimplifyShlInst(LHS, RHS, false, false, Q, MaxRecurse);
case Instruction::LShr:
  return SimplifyLShrInst(LHS, RHS, false, Q, MaxRecurse);
case Instruction::AShr:
  return SimplifyAShrInst(LHS, RHS, false, Q, MaxRecurse);
3
←
Calling 'SimplifyAShrInst'→
case Instruction::And:
  return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
case Instruction::Or:
  return SimplifyOrInst(LHS, RHS, Q, MaxRecurse);
case Instruction::Xor:
  return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
case Instruction::FAdd:
  return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
case Instruction::FSub:
  return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
case Instruction::FMul:
  return SimplifyFMulInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
case Instruction::FDiv:
  return SimplifyFDivInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
case Instruction::FRem:
  return SimplifyFRemInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse);
default:
  llvm_unreachable("Unexpected opcode")::llvm::llvm_unreachable_internal("Unexpected opcode", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 4422);
}
4424}

4426/// Given operands for a BinaryOperator, see if we can fold the result.
4427/// If not, this returns null.
4428/// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
4429/// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
4430static Value *SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
                            const FastMathFlags &FMF, const SimplifyQuery &Q,
                            unsigned MaxRecurse) {
switch (Opcode) {
case Instruction::FAdd:
  return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse);
case Instruction::FSub:
  return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse);
case Instruction::FMul:
  return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse);
case Instruction::FDiv:
  return SimplifyFDivInst(LHS, RHS, FMF, Q, MaxRecurse);
default:
  return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse);
}
4445}

4447Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
                         const SimplifyQuery &Q) {
return ::SimplifyBinOp(Opcode, LHS, RHS, Q, RecursionLimit);
1
Calling 'SimplifyBinOp'→
4450}

4452Value *llvm::SimplifyFPBinOp(unsigned Opcode, Value *LHS, Value *RHS,
                           FastMathFlags FMF, const SimplifyQuery &Q) {
return ::SimplifyFPBinOp(Opcode, LHS, RHS, FMF, Q, RecursionLimit);
4455}

4457/// Given operands for a CmpInst, see if we can fold the result.
4458static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
                            const SimplifyQuery &Q, unsigned MaxRecurse) {
if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
  return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
return SimplifyFCmpInst(Predicate, LHS, RHS, FastMathFlags(), Q, MaxRecurse);
4463}

4465Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
                           const SimplifyQuery &Q) {
return ::SimplifyCmpInst(Predicate, LHS, RHS, Q, RecursionLimit);
4468}

4470static bool IsIdempotent(Intrinsic::ID ID) {
switch (ID) {
default: return false;

// Unary idempotent: f(f(x)) = f(x)
case Intrinsic::fabs:
case Intrinsic::floor:
case Intrinsic::ceil:
case Intrinsic::trunc:
case Intrinsic::rint:
case Intrinsic::nearbyint:
case Intrinsic::round:
case Intrinsic::canonicalize:
  return true;
}
4485}

4487static Value *SimplifyRelativeLoad(Constant *Ptr, Constant *Offset,
                                 const DataLayout &DL) {
GlobalValue *PtrSym;
APInt PtrOffset;
if (!IsConstantOffsetFromGlobal(Ptr, PtrSym, PtrOffset, DL))
  return nullptr;

Type *Int8PtrTy = Type::getInt8PtrTy(Ptr->getContext());
Type *Int32Ty = Type::getInt32Ty(Ptr->getContext());
Type *Int32PtrTy = Int32Ty->getPointerTo();
Type *Int64Ty = Type::getInt64Ty(Ptr->getContext());

auto *OffsetConstInt = dyn_cast<ConstantInt>(Offset);
if (!OffsetConstInt || OffsetConstInt->getType()->getBitWidth() > 64)
  return nullptr;

uint64_t OffsetInt = OffsetConstInt->getSExtValue();
if (OffsetInt % 4 != 0)
  return nullptr;

Constant *C = ConstantExpr::getGetElementPtr(
    Int32Ty, ConstantExpr::getBitCast(Ptr, Int32PtrTy),
    ConstantInt::get(Int64Ty, OffsetInt / 4));
Constant *Loaded = ConstantFoldLoadFromConstPtr(C, Int32Ty, DL);
if (!Loaded)
  return nullptr;

auto *LoadedCE = dyn_cast<ConstantExpr>(Loaded);
if (!LoadedCE)
  return nullptr;

if (LoadedCE->getOpcode() == Instruction::Trunc) {
  LoadedCE = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
  if (!LoadedCE)
    return nullptr;
}

if (LoadedCE->getOpcode() != Instruction::Sub)
  return nullptr;

auto *LoadedLHS = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0));
if (!LoadedLHS || LoadedLHS->getOpcode() != Instruction::PtrToInt)
  return nullptr;
auto *LoadedLHSPtr = LoadedLHS->getOperand(0);

Constant *LoadedRHS = LoadedCE->getOperand(1);
GlobalValue *LoadedRHSSym;
APInt LoadedRHSOffset;
if (!IsConstantOffsetFromGlobal(LoadedRHS, LoadedRHSSym, LoadedRHSOffset,
                                DL) ||
    PtrSym != LoadedRHSSym || PtrOffset != LoadedRHSOffset)
  return nullptr;

return ConstantExpr::getBitCast(LoadedLHSPtr, Int8PtrTy);
4541}

4543static bool maskIsAllZeroOrUndef(Value *Mask) {
auto *ConstMask = dyn_cast<Constant>(Mask);
if (!ConstMask)
  return false;
if (ConstMask->isNullValue() || isa<UndefValue>(ConstMask))
  return true;
for (unsigned I = 0, E = ConstMask->getType()->getVectorNumElements(); I != E;
     ++I) {
  if (auto *MaskElt = ConstMask->getAggregateElement(I))
    if (MaskElt->isNullValue() || isa<UndefValue>(MaskElt))
      continue;
  return false;
}
return true;
4557}

4559template <typename IterTy>
4560static Value *SimplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd,
                              const SimplifyQuery &Q, unsigned MaxRecurse) {
Intrinsic::ID IID = F->getIntrinsicID();
unsigned NumOperands = std::distance(ArgBegin, ArgEnd);

// Unary Ops
if (NumOperands == 1) {
  // Perform idempotent optimizations
  if (IsIdempotent(IID)) {
    if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin)) {
      if (II->getIntrinsicID() == IID)
        return II;
    }
  }

  Value *IIOperand = *ArgBegin;
  Value *X;
  switch (IID) {
  case Intrinsic::fabs: {
    if (SignBitMustBeZero(IIOperand, Q.TLI))
      return IIOperand;
    return nullptr;
  }
  case Intrinsic::bswap: {
    // bswap(bswap(x)) -> x
    if (match(IIOperand, m_BSwap(m_Value(X))))
      return X;
    return nullptr;
  }
  case Intrinsic::bitreverse: {
    // bitreverse(bitreverse(x)) -> x
    if (match(IIOperand, m_BitReverse(m_Value(X))))
      return X;
    return nullptr;
  }
  case Intrinsic::exp: {
    // exp(log(x)) -> x
    if (Q.CxtI->hasAllowReassoc() &&
        match(IIOperand, m_Intrinsic<Intrinsic::log>(m_Value(X))))
      return X;
    return nullptr;
  }
  case Intrinsic::exp2: {
    // exp2(log2(x)) -> x
    if (Q.CxtI->hasAllowReassoc() &&
        match(IIOperand, m_Intrinsic<Intrinsic::log2>(m_Value(X))))
      return X;
    return nullptr;
  }
  case Intrinsic::log: {
    // log(exp(x)) -> x
    if (Q.CxtI->hasAllowReassoc() &&
        match(IIOperand, m_Intrinsic<Intrinsic::exp>(m_Value(X))))
      return X;
    return nullptr;
  }
  case Intrinsic::log2: {
    // log2(exp2(x)) -> x
    if (Q.CxtI->hasAllowReassoc() &&
        match(IIOperand, m_Intrinsic<Intrinsic::exp2>(m_Value(X)))) {
      return X;
    }
    return nullptr;
  }
  default:
    return nullptr;
  }
}

// Binary Ops
if (NumOperands == 2) {
  Value *LHS = *ArgBegin;
  Value *RHS = *(ArgBegin + 1);
  Type *ReturnType = F->getReturnType();

  switch (IID) {
  case Intrinsic::usub_with_overflow:
  case Intrinsic::ssub_with_overflow: {
    // X - X -> { 0, false }
    if (LHS == RHS)
      return Constant::getNullValue(ReturnType);

    // X - undef -> undef
    // undef - X -> undef
    if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
      return UndefValue::get(ReturnType);

    return nullptr;
  }
  case Intrinsic::uadd_with_overflow:
  case Intrinsic::sadd_with_overflow: {
    // X + undef -> undef
    if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
      return UndefValue::get(ReturnType);

    return nullptr;
  }
  case Intrinsic::umul_with_overflow:
  case Intrinsic::smul_with_overflow: {
    // 0 * X -> { 0, false }
    // X * 0 -> { 0, false }
    if (match(LHS, m_Zero()) || match(RHS, m_Zero()))
      return Constant::getNullValue(ReturnType);

    // undef * X -> { 0, false }
    // X * undef -> { 0, false }
    if (match(LHS, m_Undef()) || match(RHS, m_Undef()))
      return Constant::getNullValue(ReturnType);

    return nullptr;
  }
  case Intrinsic::load_relative: {
    Constant *C0 = dyn_cast<Constant>(LHS);
    Constant *C1 = dyn_cast<Constant>(RHS);
    if (C0 && C1)
      return SimplifyRelativeLoad(C0, C1, Q.DL);
    return nullptr;
  }
  case Intrinsic::powi:
    if (ConstantInt *Power = dyn_cast<ConstantInt>(RHS)) {
      // powi(x, 0) -> 1.0
      if (Power->isZero())
        return ConstantFP::get(LHS->getType(), 1.0);
      // powi(x, 1) -> x
      if (Power->isOne())
        return LHS;
    }
    return nullptr;
  default:
    return nullptr;
  }
}

// Simplify calls to llvm.masked.load.*
switch (IID) {
case Intrinsic::masked_load: {
  Value *MaskArg = ArgBegin[2];
  Value *PassthruArg = ArgBegin[3];
  // If the mask is all zeros or undef, the "passthru" argument is the result.
  if (maskIsAllZeroOrUndef(MaskArg))
    return PassthruArg;
  return nullptr;
}
default:
  return nullptr;
}
4706}

4708template <typename IterTy>
4709static Value *SimplifyCall(ImmutableCallSite CS, Value *V, IterTy ArgBegin,
                         IterTy ArgEnd, const SimplifyQuery &Q,
                         unsigned MaxRecurse) {
Type *Ty = V->getType();
if (PointerType *PTy = dyn_cast<PointerType>(Ty))
  Ty = PTy->getElementType();
FunctionType *FTy = cast<FunctionType>(Ty);

// call undef -> undef
// call null -> undef
if (isa<UndefValue>(V) || isa<ConstantPointerNull>(V))
  return UndefValue::get(FTy->getReturnType());

Function *F = dyn_cast<Function>(V);
if (!F)
  return nullptr;

if (F->isIntrinsic())
  if (Value *Ret = SimplifyIntrinsic(F, ArgBegin, ArgEnd, Q, MaxRecurse))
    return Ret;

if (!canConstantFoldCallTo(CS, F))
  return nullptr;

SmallVector<Constant *, 4> ConstantArgs;
ConstantArgs.reserve(ArgEnd - ArgBegin);
for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
  Constant *C = dyn_cast<Constant>(*I);
  if (!C)
    return nullptr;
  ConstantArgs.push_back(C);
}

return ConstantFoldCall(CS, F, ConstantArgs, Q.TLI);
4743}

4745Value *llvm::SimplifyCall(ImmutableCallSite CS, Value *V,
                        User::op_iterator ArgBegin, User::op_iterator ArgEnd,
                        const SimplifyQuery &Q) {
return ::SimplifyCall(CS, V, ArgBegin, ArgEnd, Q, RecursionLimit);
4749}

4751Value *llvm::SimplifyCall(ImmutableCallSite CS, Value *V,
                        ArrayRef<Value *> Args, const SimplifyQuery &Q) {
return ::SimplifyCall(CS, V, Args.begin(), Args.end(), Q, RecursionLimit);
4754}

4756Value *llvm::SimplifyCall(ImmutableCallSite ICS, const SimplifyQuery &Q) {
CallSite CS(const_cast<Instruction*>(ICS.getInstruction()));
return ::SimplifyCall(CS, CS.getCalledValue(), CS.arg_begin(), CS.arg_end(),
                      Q, RecursionLimit);
4760}

4762/// See if we can compute a simplified version of this instruction.
4763/// If not, this returns null.

4765Value *llvm::SimplifyInstruction(Instruction *I, const SimplifyQuery &SQ,
                               OptimizationRemarkEmitter *ORE) {
const SimplifyQuery Q = SQ.CxtI ? SQ : SQ.getWithInstruction(I);
Value *Result;

switch (I->getOpcode()) {
default:
  Result = ConstantFoldInstruction(I, Q.DL, Q.TLI);
  break;
case Instruction::FAdd:
  Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1),
                            I->getFastMathFlags(), Q);
  break;
case Instruction::Add:
  Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
                           cast<BinaryOperator>(I)->hasNoSignedWrap(),
                           cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
  break;
case Instruction::FSub:
  Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1),
                            I->getFastMathFlags(), Q);
  break;
case Instruction::Sub:
  Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
                           cast<BinaryOperator>(I)->hasNoSignedWrap(),
                           cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
  break;
case Instruction::FMul:
  Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1),
                            I->getFastMathFlags(), Q);
  break;
case Instruction::Mul:
  Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), Q);
  break;
case Instruction::SDiv:
  Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), Q);
  break;
case Instruction::UDiv:
  Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), Q);
  break;
case Instruction::FDiv:
  Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1),
                            I->getFastMathFlags(), Q);
  break;
case Instruction::SRem:
  Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), Q);
  break;
case Instruction::URem:
  Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), Q);
  break;
case Instruction::FRem:
  Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1),
                            I->getFastMathFlags(), Q);
  break;
case Instruction::Shl:
  Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
                           cast<BinaryOperator>(I)->hasNoSignedWrap(),
                           cast<BinaryOperator>(I)->hasNoUnsignedWrap(), Q);
  break;
case Instruction::LShr:
  Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
                            cast<BinaryOperator>(I)->isExact(), Q);
  break;
case Instruction::AShr:
  Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
                            cast<BinaryOperator>(I)->isExact(), Q);
  break;
case Instruction::And:
  Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), Q);
  break;
case Instruction::Or:
  Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), Q);
  break;
case Instruction::Xor:
  Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), Q);
  break;
case Instruction::ICmp:
  Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
                            I->getOperand(0), I->getOperand(1), Q);
  break;
case Instruction::FCmp:
  Result =
      SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), I->getOperand(0),
                       I->getOperand(1), I->getFastMathFlags(), Q);
  break;
case Instruction::Select:
  Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
                              I->getOperand(2), Q);
  break;
case Instruction::GetElementPtr: {
  SmallVector<Value *, 8> Ops(I->op_begin(), I->op_end());
  Result = SimplifyGEPInst(cast<GetElementPtrInst>(I)->getSourceElementType(),
                           Ops, Q);
  break;
}
case Instruction::InsertValue: {
  InsertValueInst *IV = cast<InsertValueInst>(I);
  Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
                                   IV->getInsertedValueOperand(),
                                   IV->getIndices(), Q);
  break;
}
case Instruction::InsertElement: {
  auto *IE = cast<InsertElementInst>(I);
  Result = SimplifyInsertElementInst(IE->getOperand(0), IE->getOperand(1),
                                     IE->getOperand(2), Q);
  break;
}
case Instruction::ExtractValue: {
  auto *EVI = cast<ExtractValueInst>(I);
  Result = SimplifyExtractValueInst(EVI->getAggregateOperand(),
                                    EVI->getIndices(), Q);
  break;
}
case Instruction::ExtractElement: {
  auto *EEI = cast<ExtractElementInst>(I);
  Result = SimplifyExtractElementInst(EEI->getVectorOperand(),
                                      EEI->getIndexOperand(), Q);
  break;
}
case Instruction::ShuffleVector: {
  auto *SVI = cast<ShuffleVectorInst>(I);
  Result = SimplifyShuffleVectorInst(SVI->getOperand(0), SVI->getOperand(1),
                                     SVI->getMask(), SVI->getType(), Q);
  break;
}
case Instruction::PHI:
  Result = SimplifyPHINode(cast<PHINode>(I), Q);
  break;
case Instruction::Call: {
  CallSite CS(cast<CallInst>(I));
  Result = SimplifyCall(CS, Q);
  break;
}
4899#define HANDLE_CAST_INST(num, opc, clas) case Instruction::opc:
4900#include "llvm/IR/Instruction.def"
4901#undef HANDLE_CAST_INST
  Result =
      SimplifyCastInst(I->getOpcode(), I->getOperand(0), I->getType(), Q);
  break;
case Instruction::Alloca:
  // No simplifications for Alloca and it can't be constant folded.
  Result = nullptr;
  break;
}

// In general, it is possible for computeKnownBits to determine all bits in a
// value even when the operands are not all constants.
if (!Result && I->getType()->isIntOrIntVectorTy()) {
  KnownBits Known = computeKnownBits(I, Q.DL, /*Depth*/ 0, Q.AC, I, Q.DT, ORE);
  if (Known.isConstant())
    Result = ConstantInt::get(I->getType(), Known.getConstant());
}

/// If called on unreachable code, the above logic may report that the
/// instruction simplified to itself.  Make life easier for users by
/// detecting that case here, returning a safe value instead.
return Result == I ? UndefValue::get(I->getType()) : Result;
4923}

4925/// \brief Implementation of recursive simplification through an instruction's
4926/// uses.
4927///
4928/// This is the common implementation of the recursive simplification routines.
4929/// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
4930/// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
4931/// instructions to process and attempt to simplify it using
4932/// InstructionSimplify.
4933///
4934/// This routine returns 'true' only when *it* simplifies something. The passed
4935/// in simplified value does not count toward this.
4936static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
                                            const TargetLibraryInfo *TLI,
                                            const DominatorTree *DT,
                                            AssumptionCache *AC) {
bool Simplified = false;
SmallSetVector<Instruction *, 8> Worklist;
const DataLayout &DL = I->getModule()->getDataLayout();

// If we have an explicit value to collapse to, do that round of the
// simplification loop by hand initially.
if (SimpleV) {
  for (User *U : I->users())
    if (U != I)
      Worklist.insert(cast<Instruction>(U));

  // Replace the instruction with its simplified value.
  I->replaceAllUsesWith(SimpleV);

  // Gracefully handle edge cases where the instruction is not wired into any
  // parent block.
  if (I->getParent() && !I->isEHPad() && !isa<TerminatorInst>(I) &&
      !I->mayHaveSideEffects())
    I->eraseFromParent();
} else {
  Worklist.insert(I);
}

// Note that we must test the size on each iteration, the worklist can grow.
for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
  I = Worklist[Idx];

  // See if this instruction simplifies.
  SimpleV = SimplifyInstruction(I, {DL, TLI, DT, AC});
  if (!SimpleV)
    continue;

  Simplified = true;

  // Stash away all the uses of the old instruction so we can check them for
  // recursive simplifications after a RAUW. This is cheaper than checking all
  // uses of To on the recursive step in most cases.
  for (User *U : I->users())
    Worklist.insert(cast<Instruction>(U));

  // Replace the instruction with its simplified value.
  I->replaceAllUsesWith(SimpleV);

  // Gracefully handle edge cases where the instruction is not wired into any
  // parent block.
  if (I->getParent() && !I->isEHPad() && !isa<TerminatorInst>(I) &&
      !I->mayHaveSideEffects())
    I->eraseFromParent();
}
return Simplified;
4990}

4992bool llvm::recursivelySimplifyInstruction(Instruction *I,
                                        const TargetLibraryInfo *TLI,
                                        const DominatorTree *DT,
                                        AssumptionCache *AC) {
return replaceAndRecursivelySimplifyImpl(I, nullptr, TLI, DT, AC);
4997}

4999bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
                                       const TargetLibraryInfo *TLI,
                                       const DominatorTree *DT,
                                       AssumptionCache *AC) {
assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!")(static_cast <bool> (I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!"
) ? void (0) : __assert_fail ("I != SimpleV && \"replaceAndRecursivelySimplify(X,X) is not valid!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 5003, __extension__ __PRETTY_FUNCTION__));
assert(SimpleV && "Must provide a simplified value.")(static_cast <bool> (SimpleV && "Must provide a simplified value."
) ? void (0) : __assert_fail ("SimpleV && \"Must provide a simplified value.\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/InstructionSimplify.cpp"
, 5004, __extension__ __PRETTY_FUNCTION__));
return replaceAndRecursivelySimplifyImpl(I, SimpleV, TLI, DT, AC);
5006}

5008namespace llvm {
5009const SimplifyQuery getBestSimplifyQuery(Pass &P, Function &F) {
auto *DTWP = P.getAnalysisIfAvailable<DominatorTreeWrapperPass>();
auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
auto *TLIWP = P.getAnalysisIfAvailable<TargetLibraryInfoWrapperPass>();
auto *TLI = TLIWP ? &TLIWP->getTLI() : nullptr;
auto *ACWP = P.getAnalysisIfAvailable<AssumptionCacheTracker>();
auto *AC = ACWP ? &ACWP->getAssumptionCache(F) : nullptr;
return {F.getParent()->getDataLayout(), TLI, DT, AC};
5017}

5019const SimplifyQuery getBestSimplifyQuery(LoopStandardAnalysisResults &AR,
                                       const DataLayout &DL) {
return {DL, &AR.TLI, &AR.DT, &AR.AC};
5022}

5024template <class T, class... TArgs>
5025const SimplifyQuery getBestSimplifyQuery(AnalysisManager<T, TArgs...> &AM,
                                       Function &F) {
auto *DT = AM.template getCachedResult<DominatorTreeAnalysis>(F);
auto *TLI = AM.template getCachedResult<TargetLibraryAnalysis>(F);
auto *AC = AM.template getCachedResult<AssumptionAnalysis>(F);
return {F.getParent()->getDataLayout(), TLI, DT, AC};
5031}
5032template const SimplifyQuery getBestSimplifyQuery(AnalysisManager<Function> &,
                                                Function &);
5034}