/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp

Bug Summary

File:	lib/Transforms/Scalar/Reassociate.cpp
Warning:	line 1482, column 44 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 Reassociate.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/Transforms/Scalar -I /build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar -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/Transforms/Scalar -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/Transforms/Scalar/Reassociate.cpp
1//===- Reassociate.cpp - Reassociate binary expressions -------------------===//
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 pass reassociates commutative expressions in an order that is designed
11// to promote better constant propagation, GCSE, LICM, PRE, etc.
12//
13// For example: 4 + (x + 5) -> x + (4 + 5)
14//
15// In the implementation of this algorithm, constants are assigned rank = 0,
16// function arguments are rank = 1, and other values are assigned ranks
17// corresponding to the reverse post order traversal of current function
18// (starting at 2), which effectively gives values in deep loops higher rank
19// than values not in loops.
20//
21//===----------------------------------------------------------------------===//

23#include "llvm/Transforms/Scalar/Reassociate.h"
24#include "llvm/ADT/APFloat.h"
25#include "llvm/ADT/APInt.h"
26#include "llvm/ADT/DenseMap.h"
27#include "llvm/ADT/PostOrderIterator.h"
28#include "llvm/ADT/SetVector.h"
29#include "llvm/ADT/SmallPtrSet.h"
30#include "llvm/ADT/SmallSet.h"
31#include "llvm/ADT/SmallVector.h"
32#include "llvm/ADT/Statistic.h"
33#include "llvm/Analysis/GlobalsModRef.h"
34#include "llvm/Analysis/Utils/Local.h"
35#include "llvm/Analysis/ValueTracking.h"
36#include "llvm/IR/Argument.h"
37#include "llvm/IR/BasicBlock.h"
38#include "llvm/IR/CFG.h"
39#include "llvm/IR/Constant.h"
40#include "llvm/IR/Constants.h"
41#include "llvm/IR/Function.h"
42#include "llvm/IR/IRBuilder.h"
43#include "llvm/IR/InstrTypes.h"
44#include "llvm/IR/Instruction.h"
45#include "llvm/IR/Instructions.h"
46#include "llvm/IR/Operator.h"
47#include "llvm/IR/PassManager.h"
48#include "llvm/IR/PatternMatch.h"
49#include "llvm/IR/Type.h"
50#include "llvm/IR/User.h"
51#include "llvm/IR/Value.h"
52#include "llvm/IR/ValueHandle.h"
53#include "llvm/Pass.h"
54#include "llvm/Support/Casting.h"
55#include "llvm/Support/Debug.h"
56#include "llvm/Support/ErrorHandling.h"
57#include "llvm/Support/raw_ostream.h"
58#include "llvm/Transforms/Scalar.h"
59#include <algorithm>
60#include <cassert>
61#include <utility>

63using namespace llvm;
64using namespace reassociate;

66#define DEBUG_TYPE"reassociate" "reassociate"

68STATISTIC(NumChanged, "Number of insts reassociated")static llvm::Statistic NumChanged = {"reassociate", "NumChanged"
, "Number of insts reassociated", {0}, {false}};
69STATISTIC(NumAnnihil, "Number of expr tree annihilated")static llvm::Statistic NumAnnihil = {"reassociate", "NumAnnihil"
, "Number of expr tree annihilated", {0}, {false}};
70STATISTIC(NumFactor , "Number of multiplies factored")static llvm::Statistic NumFactor = {"reassociate", "NumFactor"
, "Number of multiplies factored", {0}, {false}};

72#ifndef NDEBUG
73/// Print out the expression identified in the Ops list.
74static void PrintOps(Instruction *I, const SmallVectorImpl<ValueEntry> &Ops) {
Module *M = I->getModule();
dbgs() << Instruction::getOpcodeName(I->getOpcode()) << " "
     << *Ops[0].Op->getType() << '\t';
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
  dbgs() << "[ ";
  Ops[i].Op->printAsOperand(dbgs(), false, M);
  dbgs() << ", #" << Ops[i].Rank << "] ";
}
83}
84#endif

86/// Utility class representing a non-constant Xor-operand. We classify
87/// non-constant Xor-Operands into two categories:
88///  C1) The operand is in the form "X & C", where C is a constant and C != ~0
89///  C2)
90///    C2.1) The operand is in the form of "X | C", where C is a non-zero
91///          constant.
92///    C2.2) Any operand E which doesn't fall into C1 and C2.1, we view this
93///          operand as "E | 0"
94class llvm::reassociate::XorOpnd {
95public:
XorOpnd(Value *V);

bool isInvalid() const { return SymbolicPart == nullptr; }
bool isOrExpr() const { return isOr; }
Value *getValue() const { return OrigVal; }
Value *getSymbolicPart() const { return SymbolicPart; }
unsigned getSymbolicRank() const { return SymbolicRank; }
const APInt &getConstPart() const { return ConstPart; }

void Invalidate() { SymbolicPart = OrigVal = nullptr; }
void setSymbolicRank(unsigned R) { SymbolicRank = R; }

108private:
Value *OrigVal;
Value *SymbolicPart;
APInt ConstPart;
unsigned SymbolicRank;
bool isOr;
114};

116XorOpnd::XorOpnd(Value *V) {
assert(!isa<ConstantInt>(V) && "No ConstantInt")(static_cast <bool> (!isa<ConstantInt>(V) &&
 "No ConstantInt") ? void (0) : __assert_fail ("!isa<ConstantInt>(V) && \"No ConstantInt\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 117, __extension__ __PRETTY_FUNCTION__));
OrigVal = V;
Instruction *I = dyn_cast<Instruction>(V);
SymbolicRank = 0;

if (I && (I->getOpcode() == Instruction::Or ||
          I->getOpcode() == Instruction::And)) {
  Value *V0 = I->getOperand(0);
  Value *V1 = I->getOperand(1);
  const APInt *C;
  if (match(V0, PatternMatch::m_APInt(C)))
    std::swap(V0, V1);

  if (match(V1, PatternMatch::m_APInt(C))) {
    ConstPart = *C;
    SymbolicPart = V0;
    isOr = (I->getOpcode() == Instruction::Or);
    return;
  }
}

// view the operand as "V | 0"
SymbolicPart = V;
ConstPart = APInt::getNullValue(V->getType()->getScalarSizeInBits());
isOr = true;
142}

144/// Return true if V is an instruction of the specified opcode and if it
145/// only has one use.
146static BinaryOperator *isReassociableOp(Value *V, unsigned Opcode) {
auto *I = dyn_cast<Instruction>(V);
if (I && I->hasOneUse() && I->getOpcode() == Opcode)
  if (!isa<FPMathOperator>(I) || I->isFast())
    return cast<BinaryOperator>(I);
return nullptr;
152}

154static BinaryOperator *isReassociableOp(Value *V, unsigned Opcode1,
                                      unsigned Opcode2) {
auto *I = dyn_cast<Instruction>(V);
if (I && I->hasOneUse() &&
    (I->getOpcode() == Opcode1 || I->getOpcode() == Opcode2))
  if (!isa<FPMathOperator>(I) || I->isFast())
    return cast<BinaryOperator>(I);
return nullptr;
162}

164void ReassociatePass::BuildRankMap(Function &F,
                                 ReversePostOrderTraversal<Function*> &RPOT) {
unsigned Rank = 2;

// Assign distinct ranks to function arguments.
for (auto &Arg : F.args()) {
  ValueRankMap[&Arg] = ++Rank;
  DEBUG(dbgs() << "Calculated Rank[" << Arg.getName() << "] = " << Rankdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "Calculated Rank[" <<
 Arg.getName() << "] = " << Rank << "\n"; }
 } while (false)
               << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "Calculated Rank[" <<
 Arg.getName() << "] = " << Rank << "\n"; }
 } while (false);
}

// Traverse basic blocks in ReversePostOrder
for (BasicBlock *BB : RPOT) {
  unsigned BBRank = RankMap[BB] = ++Rank << 16;

  // Walk the basic block, adding precomputed ranks for any instructions that
  // we cannot move.  This ensures that the ranks for these instructions are
  // all different in the block.
  for (Instruction &I : *BB)
    if (mayBeMemoryDependent(I))
      ValueRankMap[&I] = ++BBRank;
}
186}

188unsigned ReassociatePass::getRank(Value *V) {
Instruction *I = dyn_cast<Instruction>(V);
if (!I) {
  if (isa<Argument>(V)) return ValueRankMap[V];   // Function argument.
  return 0;  // Otherwise it's a global or constant, rank 0.
}

if (unsigned Rank = ValueRankMap[I])
  return Rank;    // Rank already known?

// If this is an expression, return the 1+MAX(rank(LHS), rank(RHS)) so that
// we can reassociate expressions for code motion!  Since we do not recurse
// for PHI nodes, we cannot have infinite recursion here, because there
// cannot be loops in the value graph that do not go through PHI nodes.
unsigned Rank = 0, MaxRank = RankMap[I->getParent()];
for (unsigned i = 0, e = I->getNumOperands();
     i != e && Rank != MaxRank; ++i)
  Rank = std::max(Rank, getRank(I->getOperand(i)));

// If this is a not or neg instruction, do not count it for rank.  This
// assures us that X and ~X will have the same rank.
if  (!BinaryOperator::isNot(I) && !BinaryOperator::isNeg(I) &&
     !BinaryOperator::isFNeg(I))
  ++Rank;

DEBUG(dbgs() << "Calculated Rank[" << V->getName() << "] = " << Rank << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "Calculated Rank[" <<
 V->getName() << "] = " << Rank << "\n";
 } } while (false);

return ValueRankMap[I] = Rank;
216}

218// Canonicalize constants to RHS.  Otherwise, sort the operands by rank.
219void ReassociatePass::canonicalizeOperands(Instruction *I) {
assert(isa<BinaryOperator>(I) && "Expected binary operator.")(static_cast <bool> (isa<BinaryOperator>(I) &&
 "Expected binary operator.") ? void (0) : __assert_fail ("isa<BinaryOperator>(I) && \"Expected binary operator.\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 220, __extension__ __PRETTY_FUNCTION__));
assert(I->isCommutative() && "Expected commutative operator.")(static_cast <bool> (I->isCommutative() && "Expected commutative operator."
) ? void (0) : __assert_fail ("I->isCommutative() && \"Expected commutative operator.\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 221, __extension__ __PRETTY_FUNCTION__));

Value *LHS = I->getOperand(0);
Value *RHS = I->getOperand(1);
if (LHS == RHS || isa<Constant>(RHS))
  return;
if (isa<Constant>(LHS) || getRank(RHS) < getRank(LHS))
  cast<BinaryOperator>(I)->swapOperands();
229}

231static BinaryOperator *CreateAdd(Value *S1, Value *S2, const Twine &Name,
                               Instruction *InsertBefore, Value *FlagsOp) {
if (S1->getType()->isIntOrIntVectorTy())
  return BinaryOperator::CreateAdd(S1, S2, Name, InsertBefore);
else {
  BinaryOperator *Res =
      BinaryOperator::CreateFAdd(S1, S2, Name, InsertBefore);
  Res->setFastMathFlags(cast<FPMathOperator>(FlagsOp)->getFastMathFlags());
  return Res;
}
241}

243static BinaryOperator *CreateMul(Value *S1, Value *S2, const Twine &Name,
                               Instruction *InsertBefore, Value *FlagsOp) {
if (S1->getType()->isIntOrIntVectorTy())
  return BinaryOperator::CreateMul(S1, S2, Name, InsertBefore);
else {
  BinaryOperator *Res =
    BinaryOperator::CreateFMul(S1, S2, Name, InsertBefore);
  Res->setFastMathFlags(cast<FPMathOperator>(FlagsOp)->getFastMathFlags());
  return Res;
}
253}

255static BinaryOperator *CreateNeg(Value *S1, const Twine &Name,
                               Instruction *InsertBefore, Value *FlagsOp) {
if (S1->getType()->isIntOrIntVectorTy())
  return BinaryOperator::CreateNeg(S1, Name, InsertBefore);
else {
  BinaryOperator *Res = BinaryOperator::CreateFNeg(S1, Name, InsertBefore);
  Res->setFastMathFlags(cast<FPMathOperator>(FlagsOp)->getFastMathFlags());
  return Res;
}
264}

266/// Replace 0-X with X*-1.
267static BinaryOperator *LowerNegateToMultiply(Instruction *Neg) {
Type *Ty = Neg->getType();
Constant *NegOne = Ty->isIntOrIntVectorTy() ?
  ConstantInt::getAllOnesValue(Ty) : ConstantFP::get(Ty, -1.0);

BinaryOperator *Res = CreateMul(Neg->getOperand(1), NegOne, "", Neg, Neg);
Neg->setOperand(1, Constant::getNullValue(Ty)); // Drop use of op.
Res->takeName(Neg);
Neg->replaceAllUsesWith(Res);
Res->setDebugLoc(Neg->getDebugLoc());
return Res;
278}

280/// Returns k such that lambda(2^Bitwidth) = 2^k, where lambda is the Carmichael
281/// function. This means that x^(2^k) === 1 mod 2^Bitwidth for
282/// every odd x, i.e. x^(2^k) = 1 for every odd x in Bitwidth-bit arithmetic.
283/// Note that 0 <= k < Bitwidth, and if Bitwidth > 3 then x^(2^k) = 0 for every
284/// even x in Bitwidth-bit arithmetic.
285static unsigned CarmichaelShift(unsigned Bitwidth) {
if (Bitwidth < 3)
  return Bitwidth - 1;
return Bitwidth - 2;
289}

291/// Add the extra weight 'RHS' to the existing weight 'LHS',
292/// reducing the combined weight using any special properties of the operation.
293/// The existing weight LHS represents the computation X op X op ... op X where
294/// X occurs LHS times.  The combined weight represents  X op X op ... op X with
295/// X occurring LHS + RHS times.  If op is "Xor" for example then the combined
296/// operation is equivalent to X if LHS + RHS is odd, or 0 if LHS + RHS is even;
297/// the routine returns 1 in LHS in the first case, and 0 in LHS in the second.
298static void IncorporateWeight(APInt &LHS, const APInt &RHS, unsigned Opcode) {
// If we were working with infinite precision arithmetic then the combined
// weight would be LHS + RHS.  But we are using finite precision arithmetic,
// and the APInt sum LHS + RHS may not be correct if it wraps (it is correct
// for nilpotent operations and addition, but not for idempotent operations
// and multiplication), so it is important to correctly reduce the combined
// weight back into range if wrapping would be wrong.

// If RHS is zero then the weight didn't change.
if (RHS.isMinValue())
  return;
// If LHS is zero then the combined weight is RHS.
if (LHS.isMinValue()) {
  LHS = RHS;
  return;
}
// From this point on we know that neither LHS nor RHS is zero.

if (Instruction::isIdempotent(Opcode)) {
  // Idempotent means X op X === X, so any non-zero weight is equivalent to a
  // weight of 1.  Keeping weights at zero or one also means that wrapping is
  // not a problem.
  assert(LHS == 1 && RHS == 1 && "Weights not reduced!")(static_cast <bool> (LHS == 1 && RHS == 1 &&
 "Weights not reduced!") ? void (0) : __assert_fail ("LHS == 1 && RHS == 1 && \"Weights not reduced!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 320, __extension__ __PRETTY_FUNCTION__));
  return; // Return a weight of 1.
}
if (Instruction::isNilpotent(Opcode)) {
  // Nilpotent means X op X === 0, so reduce weights modulo 2.
  assert(LHS == 1 && RHS == 1 && "Weights not reduced!")(static_cast <bool> (LHS == 1 && RHS == 1 &&
 "Weights not reduced!") ? void (0) : __assert_fail ("LHS == 1 && RHS == 1 && \"Weights not reduced!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 325, __extension__ __PRETTY_FUNCTION__));
  LHS = 0; // 1 + 1 === 0 modulo 2.
  return;
}
if (Opcode == Instruction::Add || Opcode == Instruction::FAdd) {
  // TODO: Reduce the weight by exploiting nsw/nuw?
  LHS += RHS;
  return;
}

assert((Opcode == Instruction::Mul || Opcode == Instruction::FMul) &&(static_cast <bool> ((Opcode == Instruction::Mul || Opcode
 == Instruction::FMul) && "Unknown associative operation!"
) ? void (0) : __assert_fail ("(Opcode == Instruction::Mul || Opcode == Instruction::FMul) && \"Unknown associative operation!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 336, __extension__ __PRETTY_FUNCTION__))
       "Unknown associative operation!")(static_cast <bool> ((Opcode == Instruction::Mul || Opcode
 == Instruction::FMul) && "Unknown associative operation!"
) ? void (0) : __assert_fail ("(Opcode == Instruction::Mul || Opcode == Instruction::FMul) && \"Unknown associative operation!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 336, __extension__ __PRETTY_FUNCTION__));
unsigned Bitwidth = LHS.getBitWidth();
// If CM is the Carmichael number then a weight W satisfying W >= CM+Bitwidth
// can be replaced with W-CM.  That's because x^W=x^(W-CM) for every Bitwidth
// bit number x, since either x is odd in which case x^CM = 1, or x is even in
// which case both x^W and x^(W - CM) are zero.  By subtracting off multiples
// of CM like this weights can always be reduced to the range [0, CM+Bitwidth)
// which by a happy accident means that they can always be represented using
// Bitwidth bits.
// TODO: Reduce the weight by exploiting nsw/nuw?  (Could do much better than
// the Carmichael number).
if (Bitwidth > 3) {
  /// CM - The value of Carmichael's lambda function.
  APInt CM = APInt::getOneBitSet(Bitwidth, CarmichaelShift(Bitwidth));
  // Any weight W >= Threshold can be replaced with W - CM.
  APInt Threshold = CM + Bitwidth;
  assert(LHS.ult(Threshold) && RHS.ult(Threshold) && "Weights not reduced!")(static_cast <bool> (LHS.ult(Threshold) && RHS.
ult(Threshold) && "Weights not reduced!") ? void (0) :
 __assert_fail ("LHS.ult(Threshold) && RHS.ult(Threshold) && \"Weights not reduced!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 352, __extension__ __PRETTY_FUNCTION__));
  // For Bitwidth 4 or more the following sum does not overflow.
  LHS += RHS;
  while (LHS.uge(Threshold))
    LHS -= CM;
} else {
  // To avoid problems with overflow do everything the same as above but using
  // a larger type.
  unsigned CM = 1U << CarmichaelShift(Bitwidth);
  unsigned Threshold = CM + Bitwidth;
  assert(LHS.getZExtValue() < Threshold && RHS.getZExtValue() < Threshold &&(static_cast <bool> (LHS.getZExtValue() < Threshold &&
 RHS.getZExtValue() < Threshold && "Weights not reduced!"
) ? void (0) : __assert_fail ("LHS.getZExtValue() < Threshold && RHS.getZExtValue() < Threshold && \"Weights not reduced!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 363, __extension__ __PRETTY_FUNCTION__))
         "Weights not reduced!")(static_cast <bool> (LHS.getZExtValue() < Threshold &&
 RHS.getZExtValue() < Threshold && "Weights not reduced!"
) ? void (0) : __assert_fail ("LHS.getZExtValue() < Threshold && RHS.getZExtValue() < Threshold && \"Weights not reduced!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 363, __extension__ __PRETTY_FUNCTION__));
  unsigned Total = LHS.getZExtValue() + RHS.getZExtValue();
  while (Total >= Threshold)
    Total -= CM;
  LHS = Total;
}
369}

371using RepeatedValue = std::pair<Value*, APInt>;

373/// Given an associative binary expression, return the leaf
374/// nodes in Ops along with their weights (how many times the leaf occurs).  The
375/// original expression is the same as
376///   (Ops[0].first op Ops[0].first op ... Ops[0].first)  <- Ops[0].second times
377/// op
378///   (Ops[1].first op Ops[1].first op ... Ops[1].first)  <- Ops[1].second times
379/// op
380///   ...
381/// op
382///   (Ops[N].first op Ops[N].first op ... Ops[N].first)  <- Ops[N].second times
383///
384/// Note that the values Ops[0].first, ..., Ops[N].first are all distinct.
385///
386/// This routine may modify the function, in which case it returns 'true'.  The
387/// changes it makes may well be destructive, changing the value computed by 'I'
388/// to something completely different.  Thus if the routine returns 'true' then
389/// you MUST either replace I with a new expression computed from the Ops array,
390/// or use RewriteExprTree to put the values back in.
391///
392/// A leaf node is either not a binary operation of the same kind as the root
393/// node 'I' (i.e. is not a binary operator at all, or is, but with a different
394/// opcode), or is the same kind of binary operator but has a use which either
395/// does not belong to the expression, or does belong to the expression but is
396/// a leaf node.  Every leaf node has at least one use that is a non-leaf node
397/// of the expression, while for non-leaf nodes (except for the root 'I') every
398/// use is a non-leaf node of the expression.
399///
400/// For example:
401///           expression graph        node names
402///
403///                     +        |        I
404///                    / \       |
405///                   +   +      |      A,  B
406///                  / \ / \     |
407///                 *   +   *    |    C,  D,  E
408///                / \ / \ / \   |
409///                   +   *      |      F,  G
410///
411/// The leaf nodes are C, E, F and G.  The Ops array will contain (maybe not in
412/// that order) (C, 1), (E, 1), (F, 2), (G, 2).
413///
414/// The expression is maximal: if some instruction is a binary operator of the
415/// same kind as 'I', and all of its uses are non-leaf nodes of the expression,
416/// then the instruction also belongs to the expression, is not a leaf node of
417/// it, and its operands also belong to the expression (but may be leaf nodes).
418///
419/// NOTE: This routine will set operands of non-leaf non-root nodes to undef in
420/// order to ensure that every non-root node in the expression has *exactly one*
421/// use by a non-leaf node of the expression.  This destruction means that the
422/// caller MUST either replace 'I' with a new expression or use something like
423/// RewriteExprTree to put the values back in if the routine indicates that it
424/// made a change by returning 'true'.
425///
426/// In the above example either the right operand of A or the left operand of B
427/// will be replaced by undef.  If it is B's operand then this gives:
428///
429///                     +        |        I
430///                    / \       |
431///                   +   +      |      A,  B - operand of B replaced with undef
432///                  / \   \     |
433///                 *   +   *    |    C,  D,  E
434///                / \ / \ / \   |
435///                   +   *      |      F,  G
436///
437/// Note that such undef operands can only be reached by passing through 'I'.
438/// For example, if you visit operands recursively starting from a leaf node
439/// then you will never see such an undef operand unless you get back to 'I',
440/// which requires passing through a phi node.
441///
442/// Note that this routine may also mutate binary operators of the wrong type
443/// that have all uses inside the expression (i.e. only used by non-leaf nodes
444/// of the expression) if it can turn them into binary operators of the right
445/// type and thus make the expression bigger.
446static bool LinearizeExprTree(BinaryOperator *I,
                            SmallVectorImpl<RepeatedValue> &Ops) {
DEBUG(dbgs() << "LINEARIZE: " << *I << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "LINEARIZE: " << *I <<
 '\n'; } } while (false);
unsigned Bitwidth = I->getType()->getScalarType()->getPrimitiveSizeInBits();
unsigned Opcode = I->getOpcode();
assert(I->isAssociative() && I->isCommutative() &&(static_cast <bool> (I->isAssociative() && I
->isCommutative() && "Expected an associative and commutative operation!"
) ? void (0) : __assert_fail ("I->isAssociative() && I->isCommutative() && \"Expected an associative and commutative operation!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 452, __extension__ __PRETTY_FUNCTION__))
       "Expected an associative and commutative operation!")(static_cast <bool> (I->isAssociative() && I
->isCommutative() && "Expected an associative and commutative operation!"
) ? void (0) : __assert_fail ("I->isAssociative() && I->isCommutative() && \"Expected an associative and commutative operation!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 452, __extension__ __PRETTY_FUNCTION__));

// Visit all operands of the expression, keeping track of their weight (the
// number of paths from the expression root to the operand, or if you like
// the number of times that operand occurs in the linearized expression).
// For example, if I = X + A, where X = A + B, then I, X and B have weight 1
// while A has weight two.

// Worklist of non-leaf nodes (their operands are in the expression too) along
// with their weights, representing a certain number of paths to the operator.
// If an operator occurs in the worklist multiple times then we found multiple
// ways to get to it.
SmallVector<std::pair<BinaryOperator*, APInt>, 8> Worklist; // (Op, Weight)
Worklist.push_back(std::make_pair(I, APInt(Bitwidth, 1)));
bool Changed = false;

// Leaves of the expression are values that either aren't the right kind of
// operation (eg: a constant, or a multiply in an add tree), or are, but have
// some uses that are not inside the expression.  For example, in I = X + X,
// X = A + B, the value X has two uses (by I) that are in the expression.  If
// X has any other uses, for example in a return instruction, then we consider
// X to be a leaf, and won't analyze it further.  When we first visit a value,
// if it has more than one use then at first we conservatively consider it to
// be a leaf.  Later, as the expression is explored, we may discover some more
// uses of the value from inside the expression.  If all uses turn out to be
// from within the expression (and the value is a binary operator of the right
// kind) then the value is no longer considered to be a leaf, and its operands
// are explored.

// Leaves - Keeps track of the set of putative leaves as well as the number of
// paths to each leaf seen so far.
using LeafMap = DenseMap<Value *, APInt>;
LeafMap Leaves; // Leaf -> Total weight so far.
SmallVector<Value *, 8> LeafOrder; // Ensure deterministic leaf output order.

487#ifndef NDEBUG
SmallPtrSet<Value *, 8> Visited; // For sanity checking the iteration scheme.
489#endif
while (!Worklist.empty()) {
  std::pair<BinaryOperator*, APInt> P = Worklist.pop_back_val();
  I = P.first; // We examine the operands of this binary operator.

  for (unsigned OpIdx = 0; OpIdx < 2; ++OpIdx) { // Visit operands.
    Value *Op = I->getOperand(OpIdx);
    APInt Weight = P.second; // Number of paths to this operand.
    DEBUG(dbgs() << "OPERAND: " << *Op << " (" << Weight << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "OPERAND: " << *Op <<
 " (" << Weight << ")\n"; } } while (false);
    assert(!Op->use_empty() && "No uses, so how did we get to it?!")(static_cast <bool> (!Op->use_empty() && "No uses, so how did we get to it?!"
) ? void (0) : __assert_fail ("!Op->use_empty() && \"No uses, so how did we get to it?!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 498, __extension__ __PRETTY_FUNCTION__));

    // If this is a binary operation of the right kind with only one use then
    // add its operands to the expression.
    if (BinaryOperator *BO = isReassociableOp(Op, Opcode)) {
      assert(Visited.insert(Op).second && "Not first visit!")(static_cast <bool> (Visited.insert(Op).second &&
 "Not first visit!") ? void (0) : __assert_fail ("Visited.insert(Op).second && \"Not first visit!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 503, __extension__ __PRETTY_FUNCTION__));
      DEBUG(dbgs() << "DIRECT ADD: " << *Op << " (" << Weight << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "DIRECT ADD: " << *Op
 << " (" << Weight << ")\n"; } } while (false
);
      Worklist.push_back(std::make_pair(BO, Weight));
      continue;
    }

    // Appears to be a leaf.  Is the operand already in the set of leaves?
    LeafMap::iterator It = Leaves.find(Op);
    if (It == Leaves.end()) {
      // Not in the leaf map.  Must be the first time we saw this operand.
      assert(Visited.insert(Op).second && "Not first visit!")(static_cast <bool> (Visited.insert(Op).second &&
 "Not first visit!") ? void (0) : __assert_fail ("Visited.insert(Op).second && \"Not first visit!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 513, __extension__ __PRETTY_FUNCTION__));
      if (!Op->hasOneUse()) {
        // This value has uses not accounted for by the expression, so it is
        // not safe to modify.  Mark it as being a leaf.
        DEBUG(dbgs() << "ADD USES LEAF: " << *Op << " (" << Weight << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "ADD USES LEAF: " <<
 *Op << " (" << Weight << ")\n"; } } while (
false);
        LeafOrder.push_back(Op);
        Leaves[Op] = Weight;
        continue;
      }
      // No uses outside the expression, try morphing it.
    } else {
      // Already in the leaf map.
      assert(It != Leaves.end() && Visited.count(Op) &&(static_cast <bool> (It != Leaves.end() && Visited
.count(Op) && "In leaf map but not visited!") ? void (
0) : __assert_fail ("It != Leaves.end() && Visited.count(Op) && \"In leaf map but not visited!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 526, __extension__ __PRETTY_FUNCTION__))
             "In leaf map but not visited!")(static_cast <bool> (It != Leaves.end() && Visited
.count(Op) && "In leaf map but not visited!") ? void (
0) : __assert_fail ("It != Leaves.end() && Visited.count(Op) && \"In leaf map but not visited!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 526, __extension__ __PRETTY_FUNCTION__));

      // Update the number of paths to the leaf.
      IncorporateWeight(It->second, Weight, Opcode);

531#if 0   // TODO: Re-enable once PR13021 is fixed.
      // The leaf already has one use from inside the expression.  As we want
      // exactly one such use, drop this new use of the leaf.
      assert(!Op->hasOneUse() && "Only one use, but we got here twice!")(static_cast <bool> (!Op->hasOneUse() && "Only one use, but we got here twice!"
) ? void (0) : __assert_fail ("!Op->hasOneUse() && \"Only one use, but we got here twice!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 534, __extension__ __PRETTY_FUNCTION__));
      I->setOperand(OpIdx, UndefValue::get(I->getType()));
      Changed = true;

      // If the leaf is a binary operation of the right kind and we now see
      // that its multiple original uses were in fact all by nodes belonging
      // to the expression, then no longer consider it to be a leaf and add
      // its operands to the expression.
      if (BinaryOperator *BO = isReassociableOp(Op, Opcode)) {
        DEBUG(dbgs() << "UNLEAF: " << *Op << " (" << It->second << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "UNLEAF: " << *Op <<
 " (" << It->second << ")\n"; } } while (false
);
        Worklist.push_back(std::make_pair(BO, It->second));
        Leaves.erase(It);
        continue;
      }
548#endif

      // If we still have uses that are not accounted for by the expression
      // then it is not safe to modify the value.
      if (!Op->hasOneUse())
        continue;

      // No uses outside the expression, try morphing it.
      Weight = It->second;
      Leaves.erase(It); // Since the value may be morphed below.
    }

    // At this point we have a value which, first of all, is not a binary
    // expression of the right kind, and secondly, is only used inside the
    // expression.  This means that it can safely be modified.  See if we
    // can usefully morph it into an expression of the right kind.
    assert((!isa<Instruction>(Op) ||(static_cast <bool> ((!isa<Instruction>(Op) || cast
<Instruction>(Op)->getOpcode() != Opcode || (isa<
FPMathOperator>(Op) && !cast<Instruction>(Op
)->isFast())) && "Should have been handled above!"
) ? void (0) : __assert_fail ("(!isa<Instruction>(Op) || cast<Instruction>(Op)->getOpcode() != Opcode || (isa<FPMathOperator>(Op) && !cast<Instruction>(Op)->isFast())) && \"Should have been handled above!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 568, __extension__ __PRETTY_FUNCTION__))
            cast<Instruction>(Op)->getOpcode() != Opcode(static_cast <bool> ((!isa<Instruction>(Op) || cast
<Instruction>(Op)->getOpcode() != Opcode || (isa<
FPMathOperator>(Op) && !cast<Instruction>(Op
)->isFast())) && "Should have been handled above!"
) ? void (0) : __assert_fail ("(!isa<Instruction>(Op) || cast<Instruction>(Op)->getOpcode() != Opcode || (isa<FPMathOperator>(Op) && !cast<Instruction>(Op)->isFast())) && \"Should have been handled above!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 568, __extension__ __PRETTY_FUNCTION__))
            || (isa<FPMathOperator>(Op) &&(static_cast <bool> ((!isa<Instruction>(Op) || cast
<Instruction>(Op)->getOpcode() != Opcode || (isa<
FPMathOperator>(Op) && !cast<Instruction>(Op
)->isFast())) && "Should have been handled above!"
) ? void (0) : __assert_fail ("(!isa<Instruction>(Op) || cast<Instruction>(Op)->getOpcode() != Opcode || (isa<FPMathOperator>(Op) && !cast<Instruction>(Op)->isFast())) && \"Should have been handled above!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 568, __extension__ __PRETTY_FUNCTION__))
                !cast<Instruction>(Op)->isFast())) &&(static_cast <bool> ((!isa<Instruction>(Op) || cast
<Instruction>(Op)->getOpcode() != Opcode || (isa<
FPMathOperator>(Op) && !cast<Instruction>(Op
)->isFast())) && "Should have been handled above!"
) ? void (0) : __assert_fail ("(!isa<Instruction>(Op) || cast<Instruction>(Op)->getOpcode() != Opcode || (isa<FPMathOperator>(Op) && !cast<Instruction>(Op)->isFast())) && \"Should have been handled above!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 568, __extension__ __PRETTY_FUNCTION__))
           "Should have been handled above!")(static_cast <bool> ((!isa<Instruction>(Op) || cast
<Instruction>(Op)->getOpcode() != Opcode || (isa<
FPMathOperator>(Op) && !cast<Instruction>(Op
)->isFast())) && "Should have been handled above!"
) ? void (0) : __assert_fail ("(!isa<Instruction>(Op) || cast<Instruction>(Op)->getOpcode() != Opcode || (isa<FPMathOperator>(Op) && !cast<Instruction>(Op)->isFast())) && \"Should have been handled above!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 568, __extension__ __PRETTY_FUNCTION__));
    assert(Op->hasOneUse() && "Has uses outside the expression tree!")(static_cast <bool> (Op->hasOneUse() && "Has uses outside the expression tree!"
) ? void (0) : __assert_fail ("Op->hasOneUse() && \"Has uses outside the expression tree!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 569, __extension__ __PRETTY_FUNCTION__));

    // If this is a multiply expression, turn any internal negations into
    // multiplies by -1 so they can be reassociated.
    if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op))
      if ((Opcode == Instruction::Mul && BinaryOperator::isNeg(BO)) ||
          (Opcode == Instruction::FMul && BinaryOperator::isFNeg(BO))) {
        DEBUG(dbgs() << "MORPH LEAF: " << *Op << " (" << Weight << ") TO ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "MORPH LEAF: " << *Op
 << " (" << Weight << ") TO "; } } while (false
);
        BO = LowerNegateToMultiply(BO);
        DEBUG(dbgs() << *BO << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << *BO << '\n'; } } while
 (false);
        Worklist.push_back(std::make_pair(BO, Weight));
        Changed = true;
        continue;
      }

    // Failed to morph into an expression of the right type.  This really is
    // a leaf.
    DEBUG(dbgs() << "ADD LEAF: " << *Op << " (" << Weight << ")\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "ADD LEAF: " << *Op <<
 " (" << Weight << ")\n"; } } while (false);
    assert(!isReassociableOp(Op, Opcode) && "Value was morphed?")(static_cast <bool> (!isReassociableOp(Op, Opcode) &&
 "Value was morphed?") ? void (0) : __assert_fail ("!isReassociableOp(Op, Opcode) && \"Value was morphed?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 587, __extension__ __PRETTY_FUNCTION__));
    LeafOrder.push_back(Op);
    Leaves[Op] = Weight;
  }
}

// The leaves, repeated according to their weights, represent the linearized
// form of the expression.
for (unsigned i = 0, e = LeafOrder.size(); i != e; ++i) {
  Value *V = LeafOrder[i];
  LeafMap::iterator It = Leaves.find(V);
  if (It == Leaves.end())
    // Node initially thought to be a leaf wasn't.
    continue;
  assert(!isReassociableOp(V, Opcode) && "Shouldn't be a leaf!")(static_cast <bool> (!isReassociableOp(V, Opcode) &&
 "Shouldn't be a leaf!") ? void (0) : __assert_fail ("!isReassociableOp(V, Opcode) && \"Shouldn't be a leaf!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 601, __extension__ __PRETTY_FUNCTION__));
  APInt Weight = It->second;
  if (Weight.isMinValue())
    // Leaf already output or weight reduction eliminated it.
    continue;
  // Ensure the leaf is only output once.
  It->second = 0;
  Ops.push_back(std::make_pair(V, Weight));
}

// For nilpotent operations or addition there may be no operands, for example
// because the expression was "X xor X" or consisted of 2^Bitwidth additions:
// in both cases the weight reduces to 0 causing the value to be skipped.
if (Ops.empty()) {
  Constant *Identity = ConstantExpr::getBinOpIdentity(Opcode, I->getType());
  assert(Identity && "Associative operation without identity!")(static_cast <bool> (Identity && "Associative operation without identity!"
) ? void (0) : __assert_fail ("Identity && \"Associative operation without identity!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 616, __extension__ __PRETTY_FUNCTION__));
  Ops.emplace_back(Identity, APInt(Bitwidth, 1));
}

return Changed;
621}

623/// Now that the operands for this expression tree are
624/// linearized and optimized, emit them in-order.
625void ReassociatePass::RewriteExprTree(BinaryOperator *I,
                                    SmallVectorImpl<ValueEntry> &Ops) {
assert(Ops.size() > 1 && "Single values should be used directly!")(static_cast <bool> (Ops.size() > 1 && "Single values should be used directly!"
) ? void (0) : __assert_fail ("Ops.size() > 1 && \"Single values should be used directly!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 627, __extension__ __PRETTY_FUNCTION__));

// Since our optimizations should never increase the number of operations, the
// new expression can usually be written reusing the existing binary operators
// from the original expression tree, without creating any new instructions,
// though the rewritten expression may have a completely different topology.
// We take care to not change anything if the new expression will be the same
// as the original.  If more than trivial changes (like commuting operands)
// were made then we are obliged to clear out any optional subclass data like
// nsw flags.

/// NodesToRewrite - Nodes from the original expression available for writing
/// the new expression into.
SmallVector<BinaryOperator*, 8> NodesToRewrite;
unsigned Opcode = I->getOpcode();
BinaryOperator *Op = I;

/// NotRewritable - The operands being written will be the leaves of the new
/// expression and must not be used as inner nodes (via NodesToRewrite) by
/// mistake.  Inner nodes are always reassociable, and usually leaves are not
/// (if they were they would have been incorporated into the expression and so
/// would not be leaves), so most of the time there is no danger of this.  But
/// in rare cases a leaf may become reassociable if an optimization kills uses
/// of it, or it may momentarily become reassociable during rewriting (below)
/// due it being removed as an operand of one of its uses.  Ensure that misuse
/// of leaf nodes as inner nodes cannot occur by remembering all of the future
/// leaves and refusing to reuse any of them as inner nodes.
SmallPtrSet<Value*, 8> NotRewritable;
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
  NotRewritable.insert(Ops[i].Op);

// ExpressionChanged - Non-null if the rewritten expression differs from the
// original in some non-trivial way, requiring the clearing of optional flags.
// Flags are cleared from the operator in ExpressionChanged up to I inclusive.
BinaryOperator *ExpressionChanged = nullptr;
for (unsigned i = 0; ; ++i) {
  // The last operation (which comes earliest in the IR) is special as both
  // operands will come from Ops, rather than just one with the other being
  // a subexpression.
  if (i+2 == Ops.size()) {
    Value *NewLHS = Ops[i].Op;
    Value *NewRHS = Ops[i+1].Op;
    Value *OldLHS = Op->getOperand(0);
    Value *OldRHS = Op->getOperand(1);

    if (NewLHS == OldLHS && NewRHS == OldRHS)
      // Nothing changed, leave it alone.
      break;

    if (NewLHS == OldRHS && NewRHS == OldLHS) {
      // The order of the operands was reversed.  Swap them.
      DEBUG(dbgs() << "RA: " << *Op << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "RA: " << *Op <<
 '\n'; } } while (false);
      Op->swapOperands();
      DEBUG(dbgs() << "TO: " << *Op << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "TO: " << *Op <<
 '\n'; } } while (false);
      MadeChange = true;
      ++NumChanged;
      break;
    }

    // The new operation differs non-trivially from the original. Overwrite
    // the old operands with the new ones.
    DEBUG(dbgs() << "RA: " << *Op << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "RA: " << *Op <<
 '\n'; } } while (false);
    if (NewLHS != OldLHS) {
      BinaryOperator *BO = isReassociableOp(OldLHS, Opcode);
      if (BO && !NotRewritable.count(BO))
        NodesToRewrite.push_back(BO);
      Op->setOperand(0, NewLHS);
    }
    if (NewRHS != OldRHS) {
      BinaryOperator *BO = isReassociableOp(OldRHS, Opcode);
      if (BO && !NotRewritable.count(BO))
        NodesToRewrite.push_back(BO);
      Op->setOperand(1, NewRHS);
    }
    DEBUG(dbgs() << "TO: " << *Op << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "TO: " << *Op <<
 '\n'; } } while (false);

    ExpressionChanged = Op;
    MadeChange = true;
    ++NumChanged;

    break;
  }

  // Not the last operation.  The left-hand side will be a sub-expression
  // while the right-hand side will be the current element of Ops.
  Value *NewRHS = Ops[i].Op;
  if (NewRHS != Op->getOperand(1)) {
    DEBUG(dbgs() << "RA: " << *Op << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "RA: " << *Op <<
 '\n'; } } while (false);
    if (NewRHS == Op->getOperand(0)) {
      // The new right-hand side was already present as the left operand.  If
      // we are lucky then swapping the operands will sort out both of them.
      Op->swapOperands();
    } else {
      // Overwrite with the new right-hand side.
      BinaryOperator *BO = isReassociableOp(Op->getOperand(1), Opcode);
      if (BO && !NotRewritable.count(BO))
        NodesToRewrite.push_back(BO);
      Op->setOperand(1, NewRHS);
      ExpressionChanged = Op;
    }
    DEBUG(dbgs() << "TO: " << *Op << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "TO: " << *Op <<
 '\n'; } } while (false);
    MadeChange = true;
    ++NumChanged;
  }

  // Now deal with the left-hand side.  If this is already an operation node
  // from the original expression then just rewrite the rest of the expression
  // into it.
  BinaryOperator *BO = isReassociableOp(Op->getOperand(0), Opcode);
  if (BO && !NotRewritable.count(BO)) {
    Op = BO;
    continue;
  }

  // Otherwise, grab a spare node from the original expression and use that as
  // the left-hand side.  If there are no nodes left then the optimizers made
  // an expression with more nodes than the original!  This usually means that
  // they did something stupid but it might mean that the problem was just too
  // hard (finding the mimimal number of multiplications needed to realize a
  // multiplication expression is NP-complete).  Whatever the reason, smart or
  // stupid, create a new node if there are none left.
  BinaryOperator *NewOp;
  if (NodesToRewrite.empty()) {
    Constant *Undef = UndefValue::get(I->getType());
    NewOp = BinaryOperator::Create(Instruction::BinaryOps(Opcode),
                                   Undef, Undef, "", I);
    if (NewOp->getType()->isFPOrFPVectorTy())
      NewOp->setFastMathFlags(I->getFastMathFlags());
  } else {
    NewOp = NodesToRewrite.pop_back_val();
  }

  DEBUG(dbgs() << "RA: " << *Op << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "RA: " << *Op <<
 '\n'; } } while (false);
  Op->setOperand(0, NewOp);
  DEBUG(dbgs() << "TO: " << *Op << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "TO: " << *Op <<
 '\n'; } } while (false);
  ExpressionChanged = Op;
  MadeChange = true;
  ++NumChanged;
  Op = NewOp;
}

// If the expression changed non-trivially then clear out all subclass data
// starting from the operator specified in ExpressionChanged, and compactify
// the operators to just before the expression root to guarantee that the
// expression tree is dominated by all of Ops.
if (ExpressionChanged)
  do {
    // Preserve FastMathFlags.
    if (isa<FPMathOperator>(I)) {
      FastMathFlags Flags = I->getFastMathFlags();
      ExpressionChanged->clearSubclassOptionalData();
      ExpressionChanged->setFastMathFlags(Flags);
    } else
      ExpressionChanged->clearSubclassOptionalData();

    if (ExpressionChanged == I)
      break;
    ExpressionChanged->moveBefore(I);
    ExpressionChanged = cast<BinaryOperator>(*ExpressionChanged->user_begin());
  } while (true);

// Throw away any left over nodes from the original expression.
for (unsigned i = 0, e = NodesToRewrite.size(); i != e; ++i)
  RedoInsts.insert(NodesToRewrite[i]);
791}

793/// Insert instructions before the instruction pointed to by BI,
794/// that computes the negative version of the value specified.  The negative
795/// version of the value is returned, and BI is left pointing at the instruction
796/// that should be processed next by the reassociation pass.
797/// Also add intermediate instructions to the redo list that are modified while
798/// pushing the negates through adds.  These will be revisited to see if
799/// additional opportunities have been exposed.
800static Value *NegateValue(Value *V, Instruction *BI,
                        SetVector<AssertingVH<Instruction>> &ToRedo) {
if (auto *C = dyn_cast<Constant>(V))
  return C->getType()->isFPOrFPVectorTy() ? ConstantExpr::getFNeg(C) :
                                            ConstantExpr::getNeg(C);

// We are trying to expose opportunity for reassociation.  One of the things
// that we want to do to achieve this is to push a negation as deep into an
// expression chain as possible, to expose the add instructions.  In practice,
// this means that we turn this:
//   X = -(A+12+C+D)   into    X = -A + -12 + -C + -D = -12 + -A + -C + -D
// so that later, a: Y = 12+X could get reassociated with the -12 to eliminate
// the constants.  We assume that instcombine will clean up the mess later if
// we introduce tons of unnecessary negation instructions.
//
if (BinaryOperator *I =
        isReassociableOp(V, Instruction::Add, Instruction::FAdd)) {
  // Push the negates through the add.
  I->setOperand(0, NegateValue(I->getOperand(0), BI, ToRedo));
  I->setOperand(1, NegateValue(I->getOperand(1), BI, ToRedo));
  if (I->getOpcode() == Instruction::Add) {
    I->setHasNoUnsignedWrap(false);
    I->setHasNoSignedWrap(false);
  }

  // We must move the add instruction here, because the neg instructions do
  // not dominate the old add instruction in general.  By moving it, we are
  // assured that the neg instructions we just inserted dominate the
  // instruction we are about to insert after them.
  //
  I->moveBefore(BI);
  I->setName(I->getName()+".neg");

  // Add the intermediate negates to the redo list as processing them later
  // could expose more reassociating opportunities.
  ToRedo.insert(I);
  return I;
}

// Okay, we need to materialize a negated version of V with an instruction.
// Scan the use lists of V to see if we have one already.
for (User *U : V->users()) {
  if (!BinaryOperator::isNeg(U) && !BinaryOperator::isFNeg(U))
    continue;

  // We found one!  Now we have to make sure that the definition dominates
  // this use.  We do this by moving it to the entry block (if it is a
  // non-instruction value) or right after the definition.  These negates will
  // be zapped by reassociate later, so we don't need much finesse here.
  BinaryOperator *TheNeg = cast<BinaryOperator>(U);

  // Verify that the negate is in this function, V might be a constant expr.
  if (TheNeg->getParent()->getParent() != BI->getParent()->getParent())
    continue;

  BasicBlock::iterator InsertPt;
  if (Instruction *InstInput = dyn_cast<Instruction>(V)) {
    if (InvokeInst *II = dyn_cast<InvokeInst>(InstInput)) {
      InsertPt = II->getNormalDest()->begin();
    } else {
      InsertPt = ++InstInput->getIterator();
    }
    while (isa<PHINode>(InsertPt)) ++InsertPt;
  } else {
    InsertPt = TheNeg->getParent()->getParent()->getEntryBlock().begin();
  }
  TheNeg->moveBefore(&*InsertPt);
  if (TheNeg->getOpcode() == Instruction::Sub) {
    TheNeg->setHasNoUnsignedWrap(false);
    TheNeg->setHasNoSignedWrap(false);
  } else {
    TheNeg->andIRFlags(BI);
  }
  ToRedo.insert(TheNeg);
  return TheNeg;
}

// Insert a 'neg' instruction that subtracts the value from zero to get the
// negation.
BinaryOperator *NewNeg = CreateNeg(V, V->getName() + ".neg", BI, BI);
ToRedo.insert(NewNeg);
return NewNeg;
882}

884/// Return true if we should break up this subtract of X-Y into (X + -Y).
885static bool ShouldBreakUpSubtract(Instruction *Sub) {
// If this is a negation, we can't split it up!
if (BinaryOperator::isNeg(Sub) || BinaryOperator::isFNeg(Sub))
  return false;

// Don't breakup X - undef.
if (isa<UndefValue>(Sub->getOperand(1)))
  return false;

// Don't bother to break this up unless either the LHS is an associable add or
// subtract or if this is only used by one.
Value *V0 = Sub->getOperand(0);
if (isReassociableOp(V0, Instruction::Add, Instruction::FAdd) ||
    isReassociableOp(V0, Instruction::Sub, Instruction::FSub))
  return true;
Value *V1 = Sub->getOperand(1);
if (isReassociableOp(V1, Instruction::Add, Instruction::FAdd) ||
    isReassociableOp(V1, Instruction::Sub, Instruction::FSub))
  return true;
Value *VB = Sub->user_back();
if (Sub->hasOneUse() &&
    (isReassociableOp(VB, Instruction::Add, Instruction::FAdd) ||
     isReassociableOp(VB, Instruction::Sub, Instruction::FSub)))
  return true;

return false;
911}

913/// If we have (X-Y), and if either X is an add, or if this is only used by an
914/// add, transform this into (X+(0-Y)) to promote better reassociation.
915static BinaryOperator *
916BreakUpSubtract(Instruction *Sub, SetVector<AssertingVH<Instruction>> &ToRedo) {
// Convert a subtract into an add and a neg instruction. This allows sub
// instructions to be commuted with other add instructions.
//
// Calculate the negative value of Operand 1 of the sub instruction,
// and set it as the RHS of the add instruction we just made.
Value *NegVal = NegateValue(Sub->getOperand(1), Sub, ToRedo);
BinaryOperator *New = CreateAdd(Sub->getOperand(0), NegVal, "", Sub, Sub);
Sub->setOperand(0, Constant::getNullValue(Sub->getType())); // Drop use of op.
Sub->setOperand(1, Constant::getNullValue(Sub->getType())); // Drop use of op.
New->takeName(Sub);

// Everyone now refers to the add instruction.
Sub->replaceAllUsesWith(New);
New->setDebugLoc(Sub->getDebugLoc());

DEBUG(dbgs() << "Negated: " << *New << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "Negated: " << *New <<
 '\n'; } } while (false);
return New;
934}

936/// If this is a shift of a reassociable multiply or is used by one, change
937/// this into a multiply by a constant to assist with further reassociation.
938static BinaryOperator *ConvertShiftToMul(Instruction *Shl) {
Constant *MulCst = ConstantInt::get(Shl->getType(), 1);
MulCst = ConstantExpr::getShl(MulCst, cast<Constant>(Shl->getOperand(1)));

BinaryOperator *Mul =
  BinaryOperator::CreateMul(Shl->getOperand(0), MulCst, "", Shl);
Shl->setOperand(0, UndefValue::get(Shl->getType())); // Drop use of op.
Mul->takeName(Shl);

// Everyone now refers to the mul instruction.
Shl->replaceAllUsesWith(Mul);
Mul->setDebugLoc(Shl->getDebugLoc());

// We can safely preserve the nuw flag in all cases.  It's also safe to turn a
// nuw nsw shl into a nuw nsw mul.  However, nsw in isolation requires special
// handling.
bool NSW = cast<BinaryOperator>(Shl)->hasNoSignedWrap();
bool NUW = cast<BinaryOperator>(Shl)->hasNoUnsignedWrap();
if (NSW && NUW)
  Mul->setHasNoSignedWrap(true);
Mul->setHasNoUnsignedWrap(NUW);
return Mul;
960}

962/// Scan backwards and forwards among values with the same rank as element i
963/// to see if X exists.  If X does not exist, return i.  This is useful when
964/// scanning for 'x' when we see '-x' because they both get the same rank.
965static unsigned FindInOperandList(const SmallVectorImpl<ValueEntry> &Ops,
                                unsigned i, Value *X) {
unsigned XRank = Ops[i].Rank;
unsigned e = Ops.size();
for (unsigned j = i+1; j != e && Ops[j].Rank == XRank; ++j) {
  if (Ops[j].Op == X)
    return j;
  if (Instruction *I1 = dyn_cast<Instruction>(Ops[j].Op))
    if (Instruction *I2 = dyn_cast<Instruction>(X))
      if (I1->isIdenticalTo(I2))
        return j;
}
// Scan backwards.
for (unsigned j = i-1; j != ~0U && Ops[j].Rank == XRank; --j) {
  if (Ops[j].Op == X)
    return j;
  if (Instruction *I1 = dyn_cast<Instruction>(Ops[j].Op))
    if (Instruction *I2 = dyn_cast<Instruction>(X))
      if (I1->isIdenticalTo(I2))
        return j;
}
return i;
987}

989/// Emit a tree of add instructions, summing Ops together
990/// and returning the result.  Insert the tree before I.
991static Value *EmitAddTreeOfValues(Instruction *I,
                                SmallVectorImpl<WeakTrackingVH> &Ops) {
if (Ops.size() == 1) return Ops.back();

Value *V1 = Ops.back();
Ops.pop_back();
Value *V2 = EmitAddTreeOfValues(I, Ops);
return CreateAdd(V2, V1, "reass.add", I, I);
999}

1001/// If V is an expression tree that is a multiplication sequence,
1002/// and if this sequence contains a multiply by Factor,
1003/// remove Factor from the tree and return the new tree.
1004Value *ReassociatePass::RemoveFactorFromExpression(Value *V, Value *Factor) {
BinaryOperator *BO = isReassociableOp(V, Instruction::Mul, Instruction::FMul);
if (!BO)
  return nullptr;

SmallVector<RepeatedValue, 8> Tree;
MadeChange |= LinearizeExprTree(BO, Tree);
SmallVector<ValueEntry, 8> Factors;
Factors.reserve(Tree.size());
for (unsigned i = 0, e = Tree.size(); i != e; ++i) {
  RepeatedValue E = Tree[i];
  Factors.append(E.second.getZExtValue(),
                 ValueEntry(getRank(E.first), E.first));
}

bool FoundFactor = false;
bool NeedsNegate = false;
for (unsigned i = 0, e = Factors.size(); i != e; ++i) {
  if (Factors[i].Op == Factor) {
    FoundFactor = true;
    Factors.erase(Factors.begin()+i);
    break;
  }

  // If this is a negative version of this factor, remove it.
  if (ConstantInt *FC1 = dyn_cast<ConstantInt>(Factor)) {
    if (ConstantInt *FC2 = dyn_cast<ConstantInt>(Factors[i].Op))
      if (FC1->getValue() == -FC2->getValue()) {
        FoundFactor = NeedsNegate = true;
        Factors.erase(Factors.begin()+i);
        break;
      }
  } else if (ConstantFP *FC1 = dyn_cast<ConstantFP>(Factor)) {
    if (ConstantFP *FC2 = dyn_cast<ConstantFP>(Factors[i].Op)) {
      const APFloat &F1 = FC1->getValueAPF();
      APFloat F2(FC2->getValueAPF());
      F2.changeSign();
      if (F1.compare(F2) == APFloat::cmpEqual) {
        FoundFactor = NeedsNegate = true;
        Factors.erase(Factors.begin() + i);
        break;
      }
    }
  }
}

if (!FoundFactor) {
  // Make sure to restore the operands to the expression tree.
  RewriteExprTree(BO, Factors);
  return nullptr;
}

BasicBlock::iterator InsertPt = ++BO->getIterator();

// If this was just a single multiply, remove the multiply and return the only
// remaining operand.
if (Factors.size() == 1) {
  RedoInsts.insert(BO);
  V = Factors[0].Op;
} else {
  RewriteExprTree(BO, Factors);
  V = BO;
}

if (NeedsNegate)
  V = CreateNeg(V, "neg", &*InsertPt, BO);

return V;
1072}

1074/// If V is a single-use multiply, recursively add its operands as factors,
1075/// otherwise add V to the list of factors.
1076///
1077/// Ops is the top-level list of add operands we're trying to factor.
1078static void FindSingleUseMultiplyFactors(Value *V,
                                       SmallVectorImpl<Value*> &Factors) {
BinaryOperator *BO = isReassociableOp(V, Instruction::Mul, Instruction::FMul);
if (!BO) {
  Factors.push_back(V);
  return;
}

// Otherwise, add the LHS and RHS to the list of factors.
FindSingleUseMultiplyFactors(BO->getOperand(1), Factors);
FindSingleUseMultiplyFactors(BO->getOperand(0), Factors);
1089}

1091/// Optimize a series of operands to an 'and', 'or', or 'xor' instruction.
1092/// This optimizes based on identities.  If it can be reduced to a single Value,
1093/// it is returned, otherwise the Ops list is mutated as necessary.
1094static Value *OptimizeAndOrXor(unsigned Opcode,
                             SmallVectorImpl<ValueEntry> &Ops) {
// Scan the operand lists looking for X and ~X pairs, along with X,X pairs.
// If we find any, we can simplify the expression. X&~X == 0, X|~X == -1.
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
  // First, check for X and ~X in the operand list.
  assert(i < Ops.size())(static_cast <bool> (i < Ops.size()) ? void (0) : __assert_fail
 ("i < Ops.size()", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1100, __extension__ __PRETTY_FUNCTION__));
  if (BinaryOperator::isNot(Ops[i].Op)) {    // Cannot occur for ^.
    Value *X = BinaryOperator::getNotArgument(Ops[i].Op);
    unsigned FoundX = FindInOperandList(Ops, i, X);
    if (FoundX != i) {
      if (Opcode == Instruction::And)   // ...&X&~X = 0
        return Constant::getNullValue(X->getType());

      if (Opcode == Instruction::Or)    // ...|X|~X = -1
        return Constant::getAllOnesValue(X->getType());
    }
  }

  // Next, check for duplicate pairs of values, which we assume are next to
  // each other, due to our sorting criteria.
  assert(i < Ops.size())(static_cast <bool> (i < Ops.size()) ? void (0) : __assert_fail
 ("i < Ops.size()", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1115, __extension__ __PRETTY_FUNCTION__));
  if (i+1 != Ops.size() && Ops[i+1].Op == Ops[i].Op) {
    if (Opcode == Instruction::And || Opcode == Instruction::Or) {
      // Drop duplicate values for And and Or.
      Ops.erase(Ops.begin()+i);
      --i; --e;
      ++NumAnnihil;
      continue;
    }

    // Drop pairs of values for Xor.
    assert(Opcode == Instruction::Xor)(static_cast <bool> (Opcode == Instruction::Xor) ? void
 (0) : __assert_fail ("Opcode == Instruction::Xor", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1126, __extension__ __PRETTY_FUNCTION__));
    if (e == 2)
      return Constant::getNullValue(Ops[0].Op->getType());

    // Y ^ X^X -> Y
    Ops.erase(Ops.begin()+i, Ops.begin()+i+2);
    i -= 1; e -= 2;
    ++NumAnnihil;
  }
}
return nullptr;
1137}

1139/// Helper function of CombineXorOpnd(). It creates a bitwise-and
1140/// instruction with the given two operands, and return the resulting
1141/// instruction. There are two special cases: 1) if the constant operand is 0,
1142/// it will return NULL. 2) if the constant is ~0, the symbolic operand will
1143/// be returned.
1144static Value *createAndInstr(Instruction *InsertBefore, Value *Opnd,
                           const APInt &ConstOpnd) {
if (ConstOpnd.isNullValue())
  return nullptr;

if (ConstOpnd.isAllOnesValue())
  return Opnd;

Instruction *I = BinaryOperator::CreateAnd(
    Opnd, ConstantInt::get(Opnd->getType(), ConstOpnd), "and.ra",
    InsertBefore);
I->setDebugLoc(InsertBefore->getDebugLoc());
return I;
1157}

1159// Helper function of OptimizeXor(). It tries to simplify "Opnd1 ^ ConstOpnd"
1160// into "R ^ C", where C would be 0, and R is a symbolic value.
1161//
1162// If it was successful, true is returned, and the "R" and "C" is returned
1163// via "Res" and "ConstOpnd", respectively; otherwise, false is returned,
1164// and both "Res" and "ConstOpnd" remain unchanged.
1165bool ReassociatePass::CombineXorOpnd(Instruction *I, XorOpnd *Opnd1,
                                   APInt &ConstOpnd, Value *&Res) {
// Xor-Rule 1: (x | c1) ^ c2 = (x | c1) ^ (c1 ^ c1) ^ c2 
//                       = ((x | c1) ^ c1) ^ (c1 ^ c2)
//                       = (x & ~c1) ^ (c1 ^ c2)
// It is useful only when c1 == c2.
if (!Opnd1->isOrExpr() || Opnd1->getConstPart().isNullValue())
  return false;

if (!Opnd1->getValue()->hasOneUse())
  return false;

const APInt &C1 = Opnd1->getConstPart();
if (C1 != ConstOpnd)
  return false;

Value *X = Opnd1->getSymbolicPart();
Res = createAndInstr(I, X, ~C1);
// ConstOpnd was C2, now C1 ^ C2.
ConstOpnd ^= C1;

if (Instruction *T = dyn_cast<Instruction>(Opnd1->getValue()))
  RedoInsts.insert(T);
return true;
1189}
                         
1191// Helper function of OptimizeXor(). It tries to simplify
1192// "Opnd1 ^ Opnd2 ^ ConstOpnd" into "R ^ C", where C would be 0, and R is a
1193// symbolic value. 
1194// 
1195// If it was successful, true is returned, and the "R" and "C" is returned 
1196// via "Res" and "ConstOpnd", respectively (If the entire expression is
1197// evaluated to a constant, the Res is set to NULL); otherwise, false is
1198// returned, and both "Res" and "ConstOpnd" remain unchanged.
1199bool ReassociatePass::CombineXorOpnd(Instruction *I, XorOpnd *Opnd1,
                                   XorOpnd *Opnd2, APInt &ConstOpnd,
                                   Value *&Res) {
Value *X = Opnd1->getSymbolicPart();
if (X != Opnd2->getSymbolicPart())
  return false;

// This many instruction become dead.(At least "Opnd1 ^ Opnd2" will die.)
int DeadInstNum = 1;
if (Opnd1->getValue()->hasOneUse())
  DeadInstNum++;
if (Opnd2->getValue()->hasOneUse())
  DeadInstNum++;

// Xor-Rule 2:
//  (x | c1) ^ (x & c2)
//   = (x|c1) ^ (x&c2) ^ (c1 ^ c1) = ((x|c1) ^ c1) ^ (x & c2) ^ c1
//   = (x & ~c1) ^ (x & c2) ^ c1               // Xor-Rule 1
//   = (x & c3) ^ c1, where c3 = ~c1 ^ c2      // Xor-rule 3
//
if (Opnd1->isOrExpr() != Opnd2->isOrExpr()) {
  if (Opnd2->isOrExpr())
    std::swap(Opnd1, Opnd2);

  const APInt &C1 = Opnd1->getConstPart();
  const APInt &C2 = Opnd2->getConstPart();
  APInt C3((~C1) ^ C2);

  // Do not increase code size!
  if (!C3.isNullValue() && !C3.isAllOnesValue()) {
    int NewInstNum = ConstOpnd.getBoolValue() ? 1 : 2;
    if (NewInstNum > DeadInstNum)
      return false;
  }

  Res = createAndInstr(I, X, C3);
  ConstOpnd ^= C1;
} else if (Opnd1->isOrExpr()) {
  // Xor-Rule 3: (x | c1) ^ (x | c2) = (x & c3) ^ c3 where c3 = c1 ^ c2
  //
  const APInt &C1 = Opnd1->getConstPart();
  const APInt &C2 = Opnd2->getConstPart();
  APInt C3 = C1 ^ C2;
  
  // Do not increase code size
  if (!C3.isNullValue() && !C3.isAllOnesValue()) {
    int NewInstNum = ConstOpnd.getBoolValue() ? 1 : 2;
    if (NewInstNum > DeadInstNum)
      return false;
  }

  Res = createAndInstr(I, X, C3);
  ConstOpnd ^= C3;
} else {
  // Xor-Rule 4: (x & c1) ^ (x & c2) = (x & (c1^c2))
  //
  const APInt &C1 = Opnd1->getConstPart();
  const APInt &C2 = Opnd2->getConstPart();
  APInt C3 = C1 ^ C2;
  Res = createAndInstr(I, X, C3);
}

// Put the original operands in the Redo list; hope they will be deleted
// as dead code.
if (Instruction *T = dyn_cast<Instruction>(Opnd1->getValue()))
  RedoInsts.insert(T);
if (Instruction *T = dyn_cast<Instruction>(Opnd2->getValue()))
  RedoInsts.insert(T);

return true;
1269}

1271/// Optimize a series of operands to an 'xor' instruction. If it can be reduced
1272/// to a single Value, it is returned, otherwise the Ops list is mutated as
1273/// necessary.
1274Value *ReassociatePass::OptimizeXor(Instruction *I,
                                  SmallVectorImpl<ValueEntry> &Ops) {
if (Value *V = OptimizeAndOrXor(Instruction::Xor, Ops))
  return V;
    
if (Ops.size() == 1)
  return nullptr;

SmallVector<XorOpnd, 8> Opnds;
SmallVector<XorOpnd*, 8> OpndPtrs;
Type *Ty = Ops[0].Op->getType();
APInt ConstOpnd(Ty->getScalarSizeInBits(), 0);

// Step 1: Convert ValueEntry to XorOpnd
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
  Value *V = Ops[i].Op;
  const APInt *C;
  // TODO: Support non-splat vectors.
  if (match(V, PatternMatch::m_APInt(C))) {
    ConstOpnd ^= *C;
  } else {
    XorOpnd O(V);
    O.setSymbolicRank(getRank(O.getSymbolicPart()));
    Opnds.push_back(O);
  }
}

// NOTE: From this point on, do *NOT* add/delete element to/from "Opnds".
//  It would otherwise invalidate the "Opnds"'s iterator, and hence invalidate
//  the "OpndPtrs" as well. For the similar reason, do not fuse this loop
//  with the previous loop --- the iterator of the "Opnds" may be invalidated
//  when new elements are added to the vector.
for (unsigned i = 0, e = Opnds.size(); i != e; ++i)
  OpndPtrs.push_back(&Opnds[i]);

// Step 2: Sort the Xor-Operands in a way such that the operands containing
//  the same symbolic value cluster together. For instance, the input operand
//  sequence ("x | 123", "y & 456", "x & 789") will be sorted into:
//  ("x | 123", "x & 789", "y & 456").
//
//  The purpose is twofold:
//  1) Cluster together the operands sharing the same symbolic-value.
//  2) Operand having smaller symbolic-value-rank is permuted earlier, which
//     could potentially shorten crital path, and expose more loop-invariants.
//     Note that values' rank are basically defined in RPO order (FIXME).
//     So, if Rank(X) < Rank(Y) < Rank(Z), it means X is defined earlier
//     than Y which is defined earlier than Z. Permute "x | 1", "Y & 2",
//     "z" in the order of X-Y-Z is better than any other orders.
std::stable_sort(OpndPtrs.begin(), OpndPtrs.end(),
                 [](XorOpnd *LHS, XorOpnd *RHS) {
  return LHS->getSymbolicRank() < RHS->getSymbolicRank();
});

// Step 3: Combine adjacent operands
XorOpnd *PrevOpnd = nullptr;
bool Changed = false;
for (unsigned i = 0, e = Opnds.size(); i < e; i++) {
  XorOpnd *CurrOpnd = OpndPtrs[i];
  // The combined value
  Value *CV;

  // Step 3.1: Try simplifying "CurrOpnd ^ ConstOpnd"
  if (!ConstOpnd.isNullValue() &&
      CombineXorOpnd(I, CurrOpnd, ConstOpnd, CV)) {
    Changed = true;
    if (CV)
      *CurrOpnd = XorOpnd(CV);
    else {
      CurrOpnd->Invalidate();
      continue;
    }
  }

  if (!PrevOpnd || CurrOpnd->getSymbolicPart() != PrevOpnd->getSymbolicPart()) {
    PrevOpnd = CurrOpnd;
    continue;
  }

  // step 3.2: When previous and current operands share the same symbolic
  //  value, try to simplify "PrevOpnd ^ CurrOpnd ^ ConstOpnd" 
  if (CombineXorOpnd(I, CurrOpnd, PrevOpnd, ConstOpnd, CV)) {
    // Remove previous operand
    PrevOpnd->Invalidate();
    if (CV) {
      *CurrOpnd = XorOpnd(CV);
      PrevOpnd = CurrOpnd;
    } else {
      CurrOpnd->Invalidate();
      PrevOpnd = nullptr;
    }
    Changed = true;
  }
}

// Step 4: Reassemble the Ops
if (Changed) {
  Ops.clear();
  for (unsigned int i = 0, e = Opnds.size(); i < e; i++) {
    XorOpnd &O = Opnds[i];
    if (O.isInvalid())
      continue;
    ValueEntry VE(getRank(O.getValue()), O.getValue());
    Ops.push_back(VE);
  }
  if (!ConstOpnd.isNullValue()) {
    Value *C = ConstantInt::get(Ty, ConstOpnd);
    ValueEntry VE(getRank(C), C);
    Ops.push_back(VE);
  }
  unsigned Sz = Ops.size();
  if (Sz == 1)
    return Ops.back().Op;
  if (Sz == 0) {
    assert(ConstOpnd.isNullValue())(static_cast <bool> (ConstOpnd.isNullValue()) ? void (0
) : __assert_fail ("ConstOpnd.isNullValue()", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1387, __extension__ __PRETTY_FUNCTION__));
    return ConstantInt::get(Ty, ConstOpnd);
  }
}

return nullptr;
1393}

1395/// Optimize a series of operands to an 'add' instruction.  This
1396/// optimizes based on identities.  If it can be reduced to a single Value, it
1397/// is returned, otherwise the Ops list is mutated as necessary.
1398Value *ReassociatePass::OptimizeAdd(Instruction *I,
                                  SmallVectorImpl<ValueEntry> &Ops) {
// Scan the operand lists looking for X and -X pairs.  If we find any, we
// can simplify expressions like X+-X == 0 and X+~X ==-1.  While we're at it,
// scan for any
// duplicates.  We want to canonicalize Y+Y+Y+Z -> 3*Y+Z.

for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
1
Assuming 'i' is not equal to 'e'→
2
←
Loop condition is true.  Entering loop body→
  Value *TheOp = Ops[i].Op;
  // Check to see if we've seen this operand before.  If so, we factor all
  // instances of the operand together.  Due to our sorting criteria, we know
  // that these need to be next to each other in the vector.
  if (i+1 != Ops.size() && Ops[i+1].Op == TheOp) {
3
←
Assuming the condition is false→
    // Rescan the list, remove all instances of this operand from the expr.
    unsigned NumFound = 0;
    do {
      Ops.erase(Ops.begin()+i);
      ++NumFound;
    } while (i != Ops.size() && Ops[i].Op == TheOp);

    DEBUG(dbgs() << "\nFACTORING [" << NumFound << "]: " << *TheOp << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "\nFACTORING [" << NumFound
 << "]: " << *TheOp << '\n'; } } while (false
);
    ++NumFactor;

    // Insert a new multiply.
    Type *Ty = TheOp->getType();
    Constant *C = Ty->isIntOrIntVectorTy() ?
      ConstantInt::get(Ty, NumFound) : ConstantFP::get(Ty, NumFound);
    Instruction *Mul = CreateMul(TheOp, C, "factor", I, I);

    // Now that we have inserted a multiply, optimize it. This allows us to
    // handle cases that require multiple factoring steps, such as this:
    // (X*2) + (X*2) + (X*2) -> (X*2)*3 -> X*6
    RedoInsts.insert(Mul);

    // If every add operand was a duplicate, return the multiply.
    if (Ops.empty())
      return Mul;

    // Otherwise, we had some input that didn't have the dupe, such as
    // "A + A + B" -> "A*2 + B".  Add the new multiply to the list of
    // things being added by this operation.
    Ops.insert(Ops.begin(), ValueEntry(getRank(Mul), Mul));

    --i;
    e = Ops.size();
    continue;
  }

  // Check for X and -X or X and ~X in the operand list.
  if (!BinaryOperator::isNeg(TheOp) && !BinaryOperator::isFNeg(TheOp) &&
4
←
Assuming the condition is false→
      !BinaryOperator::isNot(TheOp))
    continue;

  Value *X = nullptr;
5
←
'X' initialized to a null pointer value→
  if (BinaryOperator::isNeg(TheOp) || BinaryOperator::isFNeg(TheOp))
6
←
Assuming the condition is false→
7
←
Assuming the condition is false→
8
←
Taking false branch→
    X = BinaryOperator::getNegArgument(TheOp);
  else if (BinaryOperator::isNot(TheOp))
9
←
Assuming the condition is false→
10
←
Taking false branch→
    X = BinaryOperator::getNotArgument(TheOp);

  unsigned FoundX = FindInOperandList(Ops, i, X);
  if (FoundX == i)
11
←
Taking false branch→
    continue;

  // Remove X and -X from the operand list.
  if (Ops.size() == 2 &&
12
←
Assuming the condition is false→
      (BinaryOperator::isNeg(TheOp) || BinaryOperator::isFNeg(TheOp)))
    return Constant::getNullValue(X->getType());

  // Remove X and ~X from the operand list.
  if (Ops.size() == 2 && BinaryOperator::isNot(TheOp))
13
←
Assuming the condition is false→
    return Constant::getAllOnesValue(X->getType());

  Ops.erase(Ops.begin()+i);
  if (i < FoundX)
14
←
Taking true branch→
    --FoundX;
  else
    --i;   // Need to back up an extra one.
  Ops.erase(Ops.begin()+FoundX);
  ++NumAnnihil;
  --i;     // Revisit element.
  e -= 2;  // Removed two elements.

  // if X and ~X we append -1 to the operand list.
  if (BinaryOperator::isNot(TheOp)) {
15
←
Assuming the condition is true→
16
←
Taking true branch→
    Value *V = Constant::getAllOnesValue(X->getType());
17
←
Called C++ object pointer is null
    Ops.insert(Ops.end(), ValueEntry(getRank(V), V));
    e += 1;
  }
}

// Scan the operand list, checking to see if there are any common factors
// between operands.  Consider something like A*A+A*B*C+D.  We would like to
// reassociate this to A*(A+B*C)+D, which reduces the number of multiplies.
// To efficiently find this, we count the number of times a factor occurs
// for any ADD operands that are MULs.
DenseMap<Value*, unsigned> FactorOccurrences;

// Keep track of each multiply we see, to avoid triggering on (X*4)+(X*4)
// where they are actually the same multiply.
unsigned MaxOcc = 0;
Value *MaxOccVal = nullptr;
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
  BinaryOperator *BOp =
      isReassociableOp(Ops[i].Op, Instruction::Mul, Instruction::FMul);
  if (!BOp)
    continue;

  // Compute all of the factors of this added value.
  SmallVector<Value*, 8> Factors;
  FindSingleUseMultiplyFactors(BOp, Factors);
  assert(Factors.size() > 1 && "Bad linearize!")(static_cast <bool> (Factors.size() > 1 && "Bad linearize!"
) ? void (0) : __assert_fail ("Factors.size() > 1 && \"Bad linearize!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1508, __extension__ __PRETTY_FUNCTION__));

  // Add one to FactorOccurrences for each unique factor in this op.
  SmallPtrSet<Value*, 8> Duplicates;
  for (unsigned i = 0, e = Factors.size(); i != e; ++i) {
    Value *Factor = Factors[i];
    if (!Duplicates.insert(Factor).second)
      continue;

    unsigned Occ = ++FactorOccurrences[Factor];
    if (Occ > MaxOcc) {
      MaxOcc = Occ;
      MaxOccVal = Factor;
    }

    // If Factor is a negative constant, add the negated value as a factor
    // because we can percolate the negate out.  Watch for minint, which
    // cannot be positivified.
    if (ConstantInt *CI = dyn_cast<ConstantInt>(Factor)) {
      if (CI->isNegative() && !CI->isMinValue(true)) {
        Factor = ConstantInt::get(CI->getContext(), -CI->getValue());
        if (!Duplicates.insert(Factor).second)
          continue;
        unsigned Occ = ++FactorOccurrences[Factor];
        if (Occ > MaxOcc) {
          MaxOcc = Occ;
          MaxOccVal = Factor;
        }
      }
    } else if (ConstantFP *CF = dyn_cast<ConstantFP>(Factor)) {
      if (CF->isNegative()) {
        APFloat F(CF->getValueAPF());
        F.changeSign();
        Factor = ConstantFP::get(CF->getContext(), F);
        if (!Duplicates.insert(Factor).second)
          continue;
        unsigned Occ = ++FactorOccurrences[Factor];
        if (Occ > MaxOcc) {
          MaxOcc = Occ;
          MaxOccVal = Factor;
        }
      }
    }
  }
}

// If any factor occurred more than one time, we can pull it out.
if (MaxOcc > 1) {
  DEBUG(dbgs() << "\nFACTORING [" << MaxOcc << "]: " << *MaxOccVal << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "\nFACTORING [" << MaxOcc
 << "]: " << *MaxOccVal << '\n'; } } while (
false);
  ++NumFactor;

  // Create a new instruction that uses the MaxOccVal twice.  If we don't do
  // this, we could otherwise run into situations where removing a factor
  // from an expression will drop a use of maxocc, and this can cause
  // RemoveFactorFromExpression on successive values to behave differently.
  Instruction *DummyInst =
      I->getType()->isIntOrIntVectorTy()
          ? BinaryOperator::CreateAdd(MaxOccVal, MaxOccVal)
          : BinaryOperator::CreateFAdd(MaxOccVal, MaxOccVal);

  SmallVector<WeakTrackingVH, 4> NewMulOps;
  for (unsigned i = 0; i != Ops.size(); ++i) {
    // Only try to remove factors from expressions we're allowed to.
    BinaryOperator *BOp =
        isReassociableOp(Ops[i].Op, Instruction::Mul, Instruction::FMul);
    if (!BOp)
      continue;

    if (Value *V = RemoveFactorFromExpression(Ops[i].Op, MaxOccVal)) {
      // The factorized operand may occur several times.  Convert them all in
      // one fell swoop.
      for (unsigned j = Ops.size(); j != i;) {
        --j;
        if (Ops[j].Op == Ops[i].Op) {
          NewMulOps.push_back(V);
          Ops.erase(Ops.begin()+j);
        }
      }
      --i;
    }
  }

  // No need for extra uses anymore.
  DummyInst->deleteValue();

  unsigned NumAddedValues = NewMulOps.size();
  Value *V = EmitAddTreeOfValues(I, NewMulOps);

  // Now that we have inserted the add tree, optimize it. This allows us to
  // handle cases that require multiple factoring steps, such as this:
  // A*A*B + A*A*C   -->   A*(A*B+A*C)   -->   A*(A*(B+C))
  assert(NumAddedValues > 1 && "Each occurrence should contribute a value")(static_cast <bool> (NumAddedValues > 1 && "Each occurrence should contribute a value"
) ? void (0) : __assert_fail ("NumAddedValues > 1 && \"Each occurrence should contribute a value\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1599, __extension__ __PRETTY_FUNCTION__));
  (void)NumAddedValues;
  if (Instruction *VI = dyn_cast<Instruction>(V))
    RedoInsts.insert(VI);

  // Create the multiply.
  Instruction *V2 = CreateMul(V, MaxOccVal, "reass.mul", I, I);

  // Rerun associate on the multiply in case the inner expression turned into
  // a multiply.  We want to make sure that we keep things in canonical form.
  RedoInsts.insert(V2);

  // If every add operand included the factor (e.g. "A*B + A*C"), then the
  // entire result expression is just the multiply "A*(B+C)".
  if (Ops.empty())
    return V2;

  // Otherwise, we had some input that didn't have the factor, such as
  // "A*B + A*C + D" -> "A*(B+C) + D".  Add the new multiply to the list of
  // things being added by this operation.
  Ops.insert(Ops.begin(), ValueEntry(getRank(V2), V2));
}

return nullptr;
1623}

1625/// \brief Build up a vector of value/power pairs factoring a product.
1626///
1627/// Given a series of multiplication operands, build a vector of factors and
1628/// the powers each is raised to when forming the final product. Sort them in
1629/// the order of descending power.
1630///
1631///      (x*x)          -> [(x, 2)]
1632///     ((x*x)*x)       -> [(x, 3)]
1633///   ((((x*y)*x)*y)*x) -> [(x, 3), (y, 2)]
1634///
1635/// \returns Whether any factors have a power greater than one.
1636static bool collectMultiplyFactors(SmallVectorImpl<ValueEntry> &Ops,
                                 SmallVectorImpl<Factor> &Factors) {
// FIXME: Have Ops be (ValueEntry, Multiplicity) pairs, simplifying this.
// Compute the sum of powers of simplifiable factors.
unsigned FactorPowerSum = 0;
for (unsigned Idx = 1, Size = Ops.size(); Idx < Size; ++Idx) {
  Value *Op = Ops[Idx-1].Op;

  // Count the number of occurrences of this value.
  unsigned Count = 1;
  for (; Idx < Size && Ops[Idx].Op == Op; ++Idx)
    ++Count;
  // Track for simplification all factors which occur 2 or more times.
  if (Count > 1)
    FactorPowerSum += Count;
}

// We can only simplify factors if the sum of the powers of our simplifiable
// factors is 4 or higher. When that is the case, we will *always* have
// a simplification. This is an important invariant to prevent cyclicly
// trying to simplify already minimal formations.
if (FactorPowerSum < 4)
  return false;

// Now gather the simplifiable factors, removing them from Ops.
FactorPowerSum = 0;
for (unsigned Idx = 1; Idx < Ops.size(); ++Idx) {
  Value *Op = Ops[Idx-1].Op;

  // Count the number of occurrences of this value.
  unsigned Count = 1;
  for (; Idx < Ops.size() && Ops[Idx].Op == Op; ++Idx)
    ++Count;
  if (Count == 1)
    continue;
  // Move an even number of occurrences to Factors.
  Count &= ~1U;
  Idx -= Count;
  FactorPowerSum += Count;
  Factors.push_back(Factor(Op, Count));
  Ops.erase(Ops.begin()+Idx, Ops.begin()+Idx+Count);
}

// None of the adjustments above should have reduced the sum of factor powers
// below our mininum of '4'.
assert(FactorPowerSum >= 4)(static_cast <bool> (FactorPowerSum >= 4) ? void (0)
 : __assert_fail ("FactorPowerSum >= 4", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1681, __extension__ __PRETTY_FUNCTION__));

std::stable_sort(Factors.begin(), Factors.end(),
                 [](const Factor &LHS, const Factor &RHS) {
  return LHS.Power > RHS.Power;
});
return true;
1688}

1690/// \brief Build a tree of multiplies, computing the product of Ops.
1691static Value *buildMultiplyTree(IRBuilder<> &Builder,
                              SmallVectorImpl<Value*> &Ops) {
if (Ops.size() == 1)
  return Ops.back();

Value *LHS = Ops.pop_back_val();
do {
  if (LHS->getType()->isIntOrIntVectorTy())
    LHS = Builder.CreateMul(LHS, Ops.pop_back_val());
  else
    LHS = Builder.CreateFMul(LHS, Ops.pop_back_val());
} while (!Ops.empty());

return LHS;
1705}

1707/// \brief Build a minimal multiplication DAG for (a^x)*(b^y)*(c^z)*...
1708///
1709/// Given a vector of values raised to various powers, where no two values are
1710/// equal and the powers are sorted in decreasing order, compute the minimal
1711/// DAG of multiplies to compute the final product, and return that product
1712/// value.
1713Value *
1714ReassociatePass::buildMinimalMultiplyDAG(IRBuilder<> &Builder,
                                       SmallVectorImpl<Factor> &Factors) {
assert(Factors[0].Power)(static_cast <bool> (Factors[0].Power) ? void (0) : __assert_fail
 ("Factors[0].Power", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1716, __extension__ __PRETTY_FUNCTION__));
SmallVector<Value *, 4> OuterProduct;
for (unsigned LastIdx = 0, Idx = 1, Size = Factors.size();
     Idx < Size && Factors[Idx].Power > 0; ++Idx) {
  if (Factors[Idx].Power != Factors[LastIdx].Power) {
    LastIdx = Idx;
    continue;
  }

  // We want to multiply across all the factors with the same power so that
  // we can raise them to that power as a single entity. Build a mini tree
  // for that.
  SmallVector<Value *, 4> InnerProduct;
  InnerProduct.push_back(Factors[LastIdx].Base);
  do {
    InnerProduct.push_back(Factors[Idx].Base);
    ++Idx;
  } while (Idx < Size && Factors[Idx].Power == Factors[LastIdx].Power);

  // Reset the base value of the first factor to the new expression tree.
  // We'll remove all the factors with the same power in a second pass.
  Value *M = Factors[LastIdx].Base = buildMultiplyTree(Builder, InnerProduct);
  if (Instruction *MI = dyn_cast<Instruction>(M))
    RedoInsts.insert(MI);

  LastIdx = Idx;
}
// Unique factors with equal powers -- we've folded them into the first one's
// base.
Factors.erase(std::unique(Factors.begin(), Factors.end(),
                          [](const Factor &LHS, const Factor &RHS) {
                            return LHS.Power == RHS.Power;
                          }),
              Factors.end());

// Iteratively collect the base of each factor with an add power into the
// outer product, and halve each power in preparation for squaring the
// expression.
for (unsigned Idx = 0, Size = Factors.size(); Idx != Size; ++Idx) {
  if (Factors[Idx].Power & 1)
    OuterProduct.push_back(Factors[Idx].Base);
  Factors[Idx].Power >>= 1;
}
if (Factors[0].Power) {
  Value *SquareRoot = buildMinimalMultiplyDAG(Builder, Factors);
  OuterProduct.push_back(SquareRoot);
  OuterProduct.push_back(SquareRoot);
}
if (OuterProduct.size() == 1)
  return OuterProduct.front();

Value *V = buildMultiplyTree(Builder, OuterProduct);
return V;
1769}

1771Value *ReassociatePass::OptimizeMul(BinaryOperator *I,
                                  SmallVectorImpl<ValueEntry> &Ops) {
// We can only optimize the multiplies when there is a chain of more than
// three, such that a balanced tree might require fewer total multiplies.
if (Ops.size() < 4)
  return nullptr;

// Try to turn linear trees of multiplies without other uses of the
// intermediate stages into minimal multiply DAGs with perfect sub-expression
// re-use.
SmallVector<Factor, 4> Factors;
if (!collectMultiplyFactors(Ops, Factors))
  return nullptr; // All distinct factors, so nothing left for us to do.

IRBuilder<> Builder(I);
// The reassociate transformation for FP operations is performed only
// if unsafe algebra is permitted by FastMathFlags. Propagate those flags
// to the newly generated operations.
if (auto FPI = dyn_cast<FPMathOperator>(I))
  Builder.setFastMathFlags(FPI->getFastMathFlags());

Value *V = buildMinimalMultiplyDAG(Builder, Factors);
if (Ops.empty())
  return V;

ValueEntry NewEntry = ValueEntry(getRank(V), V);
Ops.insert(std::lower_bound(Ops.begin(), Ops.end(), NewEntry), NewEntry);
return nullptr;
1799}

1801Value *ReassociatePass::OptimizeExpression(BinaryOperator *I,
                                         SmallVectorImpl<ValueEntry> &Ops) {
// Now that we have the linearized expression tree, try to optimize it.
// Start by folding any constants that we found.
Constant *Cst = nullptr;
unsigned Opcode = I->getOpcode();
while (!Ops.empty() && isa<Constant>(Ops.back().Op)) {
  Constant *C = cast<Constant>(Ops.pop_back_val().Op);
  Cst = Cst ? ConstantExpr::get(Opcode, C, Cst) : C;
}
// If there was nothing but constants then we are done.
if (Ops.empty())
  return Cst;

// Put the combined constant back at the end of the operand list, except if
// there is no point.  For example, an add of 0 gets dropped here, while a
// multiplication by zero turns the whole expression into zero.
if (Cst && Cst != ConstantExpr::getBinOpIdentity(Opcode, I->getType())) {
  if (Cst == ConstantExpr::getBinOpAbsorber(Opcode, I->getType()))
    return Cst;
  Ops.push_back(ValueEntry(0, Cst));
}

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

// Handle destructive annihilation due to identities between elements in the
// argument list here.
unsigned NumOps = Ops.size();
switch (Opcode) {
default: break;
case Instruction::And:
case Instruction::Or:
  if (Value *Result = OptimizeAndOrXor(Opcode, Ops))
    return Result;
  break;

case Instruction::Xor:
  if (Value *Result = OptimizeXor(I, Ops))
    return Result;
  break;

case Instruction::Add:
case Instruction::FAdd:
  if (Value *Result = OptimizeAdd(I, Ops))
    return Result;
  break;

case Instruction::Mul:
case Instruction::FMul:
  if (Value *Result = OptimizeMul(I, Ops))
    return Result;
  break;
}

if (Ops.size() != NumOps)
  return OptimizeExpression(I, Ops);
return nullptr;
1858}

1860// Remove dead instructions and if any operands are trivially dead add them to
1861// Insts so they will be removed as well.
1862void ReassociatePass::RecursivelyEraseDeadInsts(
  Instruction *I, SetVector<AssertingVH<Instruction>> &Insts) {
assert(isInstructionTriviallyDead(I) && "Trivially dead instructions only!")(static_cast <bool> (isInstructionTriviallyDead(I) &&
 "Trivially dead instructions only!") ? void (0) : __assert_fail
 ("isInstructionTriviallyDead(I) && \"Trivially dead instructions only!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1864, __extension__ __PRETTY_FUNCTION__));
SmallVector<Value *, 4> Ops(I->op_begin(), I->op_end());
ValueRankMap.erase(I);
Insts.remove(I);
RedoInsts.remove(I);
I->eraseFromParent();
for (auto Op : Ops)
  if (Instruction *OpInst = dyn_cast<Instruction>(Op))
    if (OpInst->use_empty())
      Insts.insert(OpInst);
1874}

1876/// Zap the given instruction, adding interesting operands to the work list.
1877void ReassociatePass::EraseInst(Instruction *I) {
assert(isInstructionTriviallyDead(I) && "Trivially dead instructions only!")(static_cast <bool> (isInstructionTriviallyDead(I) &&
 "Trivially dead instructions only!") ? void (0) : __assert_fail
 ("isInstructionTriviallyDead(I) && \"Trivially dead instructions only!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1878, __extension__ __PRETTY_FUNCTION__));
DEBUG(dbgs() << "Erasing dead inst: "; I->dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "Erasing dead inst: "; I->
dump(); } } while (false);

SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
// Erase the dead instruction.
ValueRankMap.erase(I);
RedoInsts.remove(I);
I->eraseFromParent();
// Optimize its operands.
SmallPtrSet<Instruction *, 8> Visited; // Detect self-referential nodes.
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
  if (Instruction *Op = dyn_cast<Instruction>(Ops[i])) {
    // If this is a node in an expression tree, climb to the expression root
    // and add that since that's where optimization actually happens.
    unsigned Opcode = Op->getOpcode();
    while (Op->hasOneUse() && Op->user_back()->getOpcode() == Opcode &&
           Visited.insert(Op).second)
      Op = Op->user_back();
    RedoInsts.insert(Op);
  }

MadeChange = true;
1900}

1902// Canonicalize expressions of the following form:
1903//  x + (-Constant * y) -> x - (Constant * y)
1904//  x - (-Constant * y) -> x + (Constant * y)
1905Instruction *ReassociatePass::canonicalizeNegConstExpr(Instruction *I) {
if (!I->hasOneUse() || I->getType()->isVectorTy())
  return nullptr;

// Must be a fmul or fdiv instruction.
unsigned Opcode = I->getOpcode();
if (Opcode != Instruction::FMul && Opcode != Instruction::FDiv)
  return nullptr;

auto *C0 = dyn_cast<ConstantFP>(I->getOperand(0));
auto *C1 = dyn_cast<ConstantFP>(I->getOperand(1));

// Both operands are constant, let it get constant folded away.
if (C0 && C1)
  return nullptr;

ConstantFP *CF = C0 ? C0 : C1;

// Must have one constant operand.
if (!CF)
  return nullptr;

// Must be a negative ConstantFP.
if (!CF->isNegative())
  return nullptr;

// User must be a binary operator with one or more uses.
Instruction *User = I->user_back();
if (!isa<BinaryOperator>(User) || User->use_empty())
  return nullptr;

unsigned UserOpcode = User->getOpcode();
if (UserOpcode != Instruction::FAdd && UserOpcode != Instruction::FSub)
  return nullptr;

// Subtraction is not commutative. Explicitly, the following transform is
// not valid: (-Constant * y) - x  -> x + (Constant * y)
if (!User->isCommutative() && User->getOperand(1) != I)
  return nullptr;

// Don't canonicalize x + (-Constant * y) -> x - (Constant * y), if the
// resulting subtract will be broken up later.  This can get us into an
// infinite loop during reassociation.
if (UserOpcode == Instruction::FAdd && ShouldBreakUpSubtract(User))
  return nullptr;

// Change the sign of the constant.
APFloat Val = CF->getValueAPF();
Val.changeSign();
I->setOperand(C0 ? 0 : 1, ConstantFP::get(CF->getContext(), Val));

// Canonicalize I to RHS to simplify the next bit of logic. E.g.,
// ((-Const*y) + x) -> (x + (-Const*y)).
if (User->getOperand(0) == I && User->isCommutative())
  cast<BinaryOperator>(User)->swapOperands();

Value *Op0 = User->getOperand(0);
Value *Op1 = User->getOperand(1);
BinaryOperator *NI;
switch (UserOpcode) {
default:
  llvm_unreachable("Unexpected Opcode!")::llvm::llvm_unreachable_internal("Unexpected Opcode!", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 1966);
case Instruction::FAdd:
  NI = BinaryOperator::CreateFSub(Op0, Op1);
  NI->setFastMathFlags(cast<FPMathOperator>(User)->getFastMathFlags());
  break;
case Instruction::FSub:
  NI = BinaryOperator::CreateFAdd(Op0, Op1);
  NI->setFastMathFlags(cast<FPMathOperator>(User)->getFastMathFlags());
  break;
}

NI->insertBefore(User);
NI->setName(User->getName());
User->replaceAllUsesWith(NI);
NI->setDebugLoc(I->getDebugLoc());
RedoInsts.insert(I);
MadeChange = true;
return NI;
1984}

1986/// Inspect and optimize the given instruction. Note that erasing
1987/// instructions is not allowed.
1988void ReassociatePass::OptimizeInst(Instruction *I) {
// Only consider operations that we understand.
if (!isa<BinaryOperator>(I))
  return;

if (I->getOpcode() == Instruction::Shl && isa<ConstantInt>(I->getOperand(1)))
  // If an operand of this shift is a reassociable multiply, or if the shift
  // is used by a reassociable multiply or add, turn into a multiply.
  if (isReassociableOp(I->getOperand(0), Instruction::Mul) ||
      (I->hasOneUse() &&
       (isReassociableOp(I->user_back(), Instruction::Mul) ||
        isReassociableOp(I->user_back(), Instruction::Add)))) {
    Instruction *NI = ConvertShiftToMul(I);
    RedoInsts.insert(I);
    MadeChange = true;
    I = NI;
  }

// Canonicalize negative constants out of expressions.
if (Instruction *Res = canonicalizeNegConstExpr(I))
  I = Res;

// Commute binary operators, to canonicalize the order of their operands.
// This can potentially expose more CSE opportunities, and makes writing other
// transformations simpler.
if (I->isCommutative())
  canonicalizeOperands(I);

// Don't optimize floating-point instructions unless they are 'fast'.
if (I->getType()->isFPOrFPVectorTy() && !I->isFast())
  return;

// Do not reassociate boolean (i1) expressions.  We want to preserve the
// original order of evaluation for short-circuited comparisons that
// SimplifyCFG has folded to AND/OR expressions.  If the expression
// is not further optimized, it is likely to be transformed back to a
// short-circuited form for code gen, and the source order may have been
// optimized for the most likely conditions.
if (I->getType()->isIntegerTy(1))
  return;

// If this is a subtract instruction which is not already in negate form,
// see if we can convert it to X+-Y.
if (I->getOpcode() == Instruction::Sub) {
  if (ShouldBreakUpSubtract(I)) {
    Instruction *NI = BreakUpSubtract(I, RedoInsts);
    RedoInsts.insert(I);
    MadeChange = true;
    I = NI;
  } else if (BinaryOperator::isNeg(I)) {
    // Otherwise, this is a negation.  See if the operand is a multiply tree
    // and if this is not an inner node of a multiply tree.
    if (isReassociableOp(I->getOperand(1), Instruction::Mul) &&
        (!I->hasOneUse() ||
         !isReassociableOp(I->user_back(), Instruction::Mul))) {
      Instruction *NI = LowerNegateToMultiply(I);
      // If the negate was simplified, revisit the users to see if we can
      // reassociate further.
      for (User *U : NI->users()) {
        if (BinaryOperator *Tmp = dyn_cast<BinaryOperator>(U))
          RedoInsts.insert(Tmp);
      }
      RedoInsts.insert(I);
      MadeChange = true;
      I = NI;
    }
  }
} else if (I->getOpcode() == Instruction::FSub) {
  if (ShouldBreakUpSubtract(I)) {
    Instruction *NI = BreakUpSubtract(I, RedoInsts);
    RedoInsts.insert(I);
    MadeChange = true;
    I = NI;
  } else if (BinaryOperator::isFNeg(I)) {
    // Otherwise, this is a negation.  See if the operand is a multiply tree
    // and if this is not an inner node of a multiply tree.
    if (isReassociableOp(I->getOperand(1), Instruction::FMul) &&
        (!I->hasOneUse() ||
         !isReassociableOp(I->user_back(), Instruction::FMul))) {
      // If the negate was simplified, revisit the users to see if we can
      // reassociate further.
      Instruction *NI = LowerNegateToMultiply(I);
      for (User *U : NI->users()) {
        if (BinaryOperator *Tmp = dyn_cast<BinaryOperator>(U))
          RedoInsts.insert(Tmp);
      }
      RedoInsts.insert(I);
      MadeChange = true;
      I = NI;
    }
  }
}

// If this instruction is an associative binary operator, process it.
if (!I->isAssociative()) return;
BinaryOperator *BO = cast<BinaryOperator>(I);

// If this is an interior node of a reassociable tree, ignore it until we
// get to the root of the tree, to avoid N^2 analysis.
unsigned Opcode = BO->getOpcode();
if (BO->hasOneUse() && BO->user_back()->getOpcode() == Opcode) {
  // During the initial run we will get to the root of the tree.
  // But if we get here while we are redoing instructions, there is no
  // guarantee that the root will be visited. So Redo later
  if (BO->user_back() != BO &&
      BO->getParent() == BO->user_back()->getParent())
    RedoInsts.insert(BO->user_back());
  return;
}

// If this is an add tree that is used by a sub instruction, ignore it
// until we process the subtract.
if (BO->hasOneUse() && BO->getOpcode() == Instruction::Add &&
    cast<Instruction>(BO->user_back())->getOpcode() == Instruction::Sub)
  return;
if (BO->hasOneUse() && BO->getOpcode() == Instruction::FAdd &&
    cast<Instruction>(BO->user_back())->getOpcode() == Instruction::FSub)
  return;

ReassociateExpression(BO);
2108}

2110void ReassociatePass::ReassociateExpression(BinaryOperator *I) {
// First, walk the expression tree, linearizing the tree, collecting the
// operand information.
SmallVector<RepeatedValue, 8> Tree;
MadeChange |= LinearizeExprTree(I, Tree);
SmallVector<ValueEntry, 8> Ops;
Ops.reserve(Tree.size());
for (unsigned i = 0, e = Tree.size(); i != e; ++i) {
  RepeatedValue E = Tree[i];
  Ops.append(E.second.getZExtValue(),
             ValueEntry(getRank(E.first), E.first));
}

DEBUG(dbgs() << "RAIn:\t"; PrintOps(I, Ops); dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "RAIn:\t"; PrintOps(I, Ops
); dbgs() << '\n'; } } while (false);

// Now that we have linearized the tree to a list and have gathered all of
// the operands and their ranks, sort the operands by their rank.  Use a
// stable_sort so that values with equal ranks will have their relative
// positions maintained (and so the compiler is deterministic).  Note that
// this sorts so that the highest ranking values end up at the beginning of
// the vector.
std::stable_sort(Ops.begin(), Ops.end());

// Now that we have the expression tree in a convenient
// sorted form, optimize it globally if possible.
if (Value *V = OptimizeExpression(I, Ops)) {
  if (V == I)
    // Self-referential expression in unreachable code.
    return;
  // This expression tree simplified to something that isn't a tree,
  // eliminate it.
  DEBUG(dbgs() << "Reassoc to scalar: " << *V << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "Reassoc to scalar: " <<
 *V << '\n'; } } while (false);
  I->replaceAllUsesWith(V);
  if (Instruction *VI = dyn_cast<Instruction>(V))
    if (I->getDebugLoc())
      VI->setDebugLoc(I->getDebugLoc());
  RedoInsts.insert(I);
  ++NumAnnihil;
  return;
}

// We want to sink immediates as deeply as possible except in the case where
// this is a multiply tree used only by an add, and the immediate is a -1.
// In this case we reassociate to put the negation on the outside so that we
// can fold the negation into the add: (-X)*Y + Z -> Z-X*Y
if (I->hasOneUse()) {
  if (I->getOpcode() == Instruction::Mul &&
      cast<Instruction>(I->user_back())->getOpcode() == Instruction::Add &&
      isa<ConstantInt>(Ops.back().Op) &&
      cast<ConstantInt>(Ops.back().Op)->isMinusOne()) {
    ValueEntry Tmp = Ops.pop_back_val();
    Ops.insert(Ops.begin(), Tmp);
  } else if (I->getOpcode() == Instruction::FMul &&
             cast<Instruction>(I->user_back())->getOpcode() ==
                 Instruction::FAdd &&
             isa<ConstantFP>(Ops.back().Op) &&
             cast<ConstantFP>(Ops.back().Op)->isExactlyValue(-1.0)) {
    ValueEntry Tmp = Ops.pop_back_val();
    Ops.insert(Ops.begin(), Tmp);
  }
}

DEBUG(dbgs() << "RAOut:\t"; PrintOps(I, Ops); dbgs() << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("reassociate")) { dbgs() << "RAOut:\t"; PrintOps(I, Ops
); dbgs() << '\n'; } } while (false);

if (Ops.size() == 1) {
  if (Ops[0].Op == I)
    // Self-referential expression in unreachable code.
    return;

  // This expression tree simplified to something that isn't a tree,
  // eliminate it.
  I->replaceAllUsesWith(Ops[0].Op);
  if (Instruction *OI = dyn_cast<Instruction>(Ops[0].Op))
    OI->setDebugLoc(I->getDebugLoc());
  RedoInsts.insert(I);
  return;
}

if (Ops.size() > 2 && Ops.size() <= GlobalReassociateLimit) {
  // Find the pair with the highest count in the pairmap and move it to the
  // back of the list so that it can later be CSE'd.
  // example:
  //   a*b*c*d*e
  // if c*e is the most "popular" pair, we can express this as
  //   (((c*e)*d)*b)*a
  unsigned Max = 1;
  unsigned BestRank = 0;
  std::pair<unsigned, unsigned> BestPair;
  unsigned Idx = I->getOpcode() - Instruction::BinaryOpsBegin;
  for (unsigned i = 0; i < Ops.size() - 1; ++i)
    for (unsigned j = i + 1; j < Ops.size(); ++j) {
      unsigned Score = 0;
      Value *Op0 = Ops[i].Op;
      Value *Op1 = Ops[j].Op;
      if (std::less<Value *>()(Op1, Op0))
        std::swap(Op0, Op1);
      auto it = PairMap[Idx].find({Op0, Op1});
      if (it != PairMap[Idx].end())
        Score += it->second;

      unsigned MaxRank = std::max(Ops[i].Rank, Ops[j].Rank);
      if (Score > Max || (Score == Max && MaxRank < BestRank)) {
        BestPair = {i, j};
        Max = Score;
        BestRank = MaxRank;
      }
    }
  if (Max > 1) {
    auto Op0 = Ops[BestPair.first];
    auto Op1 = Ops[BestPair.second];
    Ops.erase(&Ops[BestPair.second]);
    Ops.erase(&Ops[BestPair.first]);
    Ops.push_back(Op0);
    Ops.push_back(Op1);
  }
}
// Now that we ordered and optimized the expressions, splat them back into
// the expression tree, removing any unneeded nodes.
RewriteExprTree(I, Ops);
2229}

2231void
2232ReassociatePass::BuildPairMap(ReversePostOrderTraversal<Function *> &RPOT) {
// Make a "pairmap" of how often each operand pair occurs.
for (BasicBlock *BI : RPOT) {
  for (Instruction &I : *BI) {
    if (!I.isAssociative())
      continue;

    // Ignore nodes that aren't at the root of trees.
    if (I.hasOneUse() && I.user_back()->getOpcode() == I.getOpcode())
      continue;

    // Collect all operands in a single reassociable expression.
    // Since Reassociate has already been run once, we can assume things
    // are already canonical according to Reassociation's regime.
    SmallVector<Value *, 8> Worklist = { I.getOperand(0), I.getOperand(1) };
    SmallVector<Value *, 8> Ops;
    while (!Worklist.empty() && Ops.size() <= GlobalReassociateLimit) {
      Value *Op = Worklist.pop_back_val();
      Instruction *OpI = dyn_cast<Instruction>(Op);
      if (!OpI || OpI->getOpcode() != I.getOpcode() || !OpI->hasOneUse()) {
        Ops.push_back(Op);
        continue;
      }
      // Be paranoid about self-referencing expressions in unreachable code.
      if (OpI->getOperand(0) != OpI)
        Worklist.push_back(OpI->getOperand(0));
      if (OpI->getOperand(1) != OpI)
        Worklist.push_back(OpI->getOperand(1));
    }
    // Skip extremely long expressions.
    if (Ops.size() > GlobalReassociateLimit)
      continue;

    // Add all pairwise combinations of operands to the pair map.
    unsigned BinaryIdx = I.getOpcode() - Instruction::BinaryOpsBegin;
    SmallSet<std::pair<Value *, Value*>, 32> Visited;
    for (unsigned i = 0; i < Ops.size() - 1; ++i) {
      for (unsigned j = i + 1; j < Ops.size(); ++j) {
        // Canonicalize operand orderings.
        Value *Op0 = Ops[i];
        Value *Op1 = Ops[j];
        if (std::less<Value *>()(Op1, Op0))
          std::swap(Op0, Op1);
        if (!Visited.insert({Op0, Op1}).second)
          continue;
        auto res = PairMap[BinaryIdx].insert({{Op0, Op1}, 1});
        if (!res.second)
          ++res.first->second;
      }
    }
  }
}
2284}

2286PreservedAnalyses ReassociatePass::run(Function &F, FunctionAnalysisManager &) {
// Get the functions basic blocks in Reverse Post Order. This order is used by
// BuildRankMap to pre calculate ranks correctly. It also excludes dead basic
// blocks (it has been seen that the analysis in this pass could hang when
// analysing dead basic blocks).
ReversePostOrderTraversal<Function *> RPOT(&F);

// Calculate the rank map for F.
BuildRankMap(F, RPOT);

// Build the pair map before running reassociate.
// Technically this would be more accurate if we did it after one round
// of reassociation, but in practice it doesn't seem to help much on
// real-world code, so don't waste the compile time running reassociate
// twice.
// If a user wants, they could expicitly run reassociate twice in their
// pass pipeline for further potential gains.
// It might also be possible to update the pair map during runtime, but the
// overhead of that may be large if there's many reassociable chains.
BuildPairMap(RPOT);

MadeChange = false;

// Traverse the same blocks that were analysed by BuildRankMap.
for (BasicBlock *BI : RPOT) {
  assert(RankMap.count(&*BI) && "BB should be ranked.")(static_cast <bool> (RankMap.count(&*BI) &&
 "BB should be ranked.") ? void (0) : __assert_fail ("RankMap.count(&*BI) && \"BB should be ranked.\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 2311, __extension__ __PRETTY_FUNCTION__));
  // Optimize every instruction in the basic block.
  for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE;)
    if (isInstructionTriviallyDead(&*II)) {
      EraseInst(&*II++);
    } else {
      OptimizeInst(&*II);
      assert(II->getParent() == &*BI && "Moved to a different block!")(static_cast <bool> (II->getParent() == &*BI &&
 "Moved to a different block!") ? void (0) : __assert_fail ("II->getParent() == &*BI && \"Moved to a different block!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Transforms/Scalar/Reassociate.cpp"
, 2318, __extension__ __PRETTY_FUNCTION__));
      ++II;
    }

  // Make a copy of all the instructions to be redone so we can remove dead
  // instructions.
  SetVector<AssertingVH<Instruction>> ToRedo(RedoInsts);
  // Iterate over all instructions to be reevaluated and remove trivially dead
  // instructions. If any operand of the trivially dead instruction becomes
  // dead mark it for deletion as well. Continue this process until all
  // trivially dead instructions have been removed.
  while (!ToRedo.empty()) {
    Instruction *I = ToRedo.pop_back_val();
    if (isInstructionTriviallyDead(I)) {
      RecursivelyEraseDeadInsts(I, ToRedo);
      MadeChange = true;
    }
  }

  // Now that we have removed dead instructions, we can reoptimize the
  // remaining instructions.
  while (!RedoInsts.empty()) {
    Instruction *I = RedoInsts.pop_back_val();
    if (isInstructionTriviallyDead(I))
      EraseInst(I);
    else
      OptimizeInst(I);
  }
}

// We are done with the rank map and pair map.
RankMap.clear();
ValueRankMap.clear();
for (auto &Entry : PairMap)
  Entry.clear();

if (MadeChange) {
  PreservedAnalyses PA;
  PA.preserveSet<CFGAnalyses>();
  PA.preserve<GlobalsAA>();
  return PA;
}

return PreservedAnalyses::all();
2362}

2364namespace {

class ReassociateLegacyPass : public FunctionPass {
  ReassociatePass Impl;

public:
  static char ID; // Pass identification, replacement for typeid

  ReassociateLegacyPass() : FunctionPass(ID) {
    initializeReassociateLegacyPassPass(*PassRegistry::getPassRegistry());
  }

  bool runOnFunction(Function &F) override {
    if (skipFunction(F))
      return false;

    FunctionAnalysisManager DummyFAM;
    auto PA = Impl.run(F, DummyFAM);
    return !PA.areAllPreserved();
  }

  void getAnalysisUsage(AnalysisUsage &AU) const override {
    AU.setPreservesCFG();
    AU.addPreserved<GlobalsAAWrapperPass>();
  }
};

2391} // end anonymous namespace

2393char ReassociateLegacyPass::ID = 0;

2395INITIALIZE_PASS(ReassociateLegacyPass, "reassociate",static void *initializeReassociateLegacyPassPassOnce(PassRegistry
 &Registry) { PassInfo *PI = new PassInfo( "Reassociate expressions"
, "reassociate", &ReassociateLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<ReassociateLegacyPass>), false, false)
; Registry.registerPass(*PI, true); return PI; } static llvm::
once_flag InitializeReassociateLegacyPassPassFlag; void llvm::
initializeReassociateLegacyPassPass(PassRegistry &Registry
) { llvm::call_once(InitializeReassociateLegacyPassPassFlag, initializeReassociateLegacyPassPassOnce
, std::ref(Registry)); }
              "Reassociate expressions", false, false)static void *initializeReassociateLegacyPassPassOnce(PassRegistry
 &Registry) { PassInfo *PI = new PassInfo( "Reassociate expressions"
, "reassociate", &ReassociateLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<ReassociateLegacyPass>), false, false)
; Registry.registerPass(*PI, true); return PI; } static llvm::
once_flag InitializeReassociateLegacyPassPassFlag; void llvm::
initializeReassociateLegacyPassPass(PassRegistry &Registry
) { llvm::call_once(InitializeReassociateLegacyPassPassFlag, initializeReassociateLegacyPassPassOnce
, std::ref(Registry)); }

2398// Public interface to the Reassociate pass
2399FunctionPass *llvm::createReassociatePass() {
return new ReassociateLegacyPass();
2401}