caio/clang-p2996
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
4794bbffb228894de3ca0dad50fc027eb94f743e
clang-p2996/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
Nikita Popov fc18a88231 [InstCombine] Avoid creating float binop ConstantExprs 
Replace ConstantExpr:getFAdd etc with call to
ConstantFoldBinaryOpOperands(). I'm using the constant folding API
rather than IRBuilder here to ensure that this does actually
constant fold. These transforms don't use m_ImmConstant(), so this
would not otherwise be guaranteed (and apparently, they can't use
m_ImmConstant because they want to handle scalable vector splats).

There is an opportunity here to further migrate these to the
ConstantFoldFPInstOperands() API, which would respect the denormal
mode. I've held off on doing so here, because some of this code
explicitly checks for denormal results, and I don't want to touch
it in a mostly NFC change.
2022-07-08 16:36:04 +02:00

1635 lines
62 KiB
C++
Raw Blame History

//===- InstCombineMulDivRem.cpp -------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the visit functions for mul, fmul, sdiv, udiv, fdiv,
// srem, urem, frem.
//
//===----------------------------------------------------------------------===//
#include "InstCombineInternal.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Transforms/InstCombine/InstCombiner.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
#include <cassert>
#define DEBUG_TYPE "instcombine"
#include "llvm/Transforms/Utils/InstructionWorklist.h"
using namespace llvm;
using namespace PatternMatch;
/// The specific integer value is used in a context where it is known to be
/// non-zero. If this allows us to simplify the computation, do so and return
/// the new operand, otherwise return null.
static Value *simplifyValueKnownNonZero(Value *V, InstCombinerImpl &IC,
Instruction &CxtI) {
// If V has multiple uses, then we would have to do more analysis to determine
// if this is safe. For example, the use could be in dynamically unreached
// code.
if (!V->hasOneUse()) return nullptr;
bool MadeChange = false;
// ((1 << A) >>u B) --> (1 << (A-B))
// Because V cannot be zero, we know that B is less than A.
Value *A = nullptr, *B = nullptr, *One = nullptr;
if (match(V, m_LShr(m_OneUse(m_Shl(m_Value(One), m_Value(A))), m_Value(B))) &&
match(One, m_One())) {
A = IC.Builder.CreateSub(A, B);
return IC.Builder.CreateShl(One, A);
}
// (PowerOfTwo >>u B) --> isExact since shifting out the result would make it
// inexact. Similarly for <<.
BinaryOperator *I = dyn_cast<BinaryOperator>(V);
if (I && I->isLogicalShift() &&
IC.isKnownToBeAPowerOfTwo(I->getOperand(0), false, 0, &CxtI)) {
// We know that this is an exact/nuw shift and that the input is a
// non-zero context as well.
if (Value *V2 = simplifyValueKnownNonZero(I->getOperand(0), IC, CxtI)) {
IC.replaceOperand(*I, 0, V2);
MadeChange = true;
}
if (I->getOpcode() == Instruction::LShr && !I->isExact()) {
I->setIsExact();
MadeChange = true;
}
if (I->getOpcode() == Instruction::Shl && !I->hasNoUnsignedWrap()) {
I->setHasNoUnsignedWrap();
MadeChange = true;
}
}
// TODO: Lots more we could do here:
// If V is a phi node, we can call this on each of its operands.
// "select cond, X, 0" can simplify to "X".
return MadeChange ? V : nullptr;
}
// TODO: This is a specific form of a much more general pattern.
// We could detect a select with any binop identity constant, or we
// could use SimplifyBinOp to see if either arm of the select reduces.
// But that needs to be done carefully and/or while removing potential
// reverse canonicalizations as in InstCombiner::foldSelectIntoOp().
static Value *foldMulSelectToNegate(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
Value *Cond, *OtherOp;
// mul (select Cond, 1, -1), OtherOp --> select Cond, OtherOp, -OtherOp
// mul OtherOp, (select Cond, 1, -1) --> select Cond, OtherOp, -OtherOp
if (match(&I, m_c_Mul(m_OneUse(m_Select(m_Value(Cond), m_One(), m_AllOnes())),
m_Value(OtherOp)))) {
bool HasAnyNoWrap = I.hasNoSignedWrap() || I.hasNoUnsignedWrap();
Value *Neg = Builder.CreateNeg(OtherOp, "", false, HasAnyNoWrap);
return Builder.CreateSelect(Cond, OtherOp, Neg);
}
// mul (select Cond, -1, 1), OtherOp --> select Cond, -OtherOp, OtherOp
// mul OtherOp, (select Cond, -1, 1) --> select Cond, -OtherOp, OtherOp
if (match(&I, m_c_Mul(m_OneUse(m_Select(m_Value(Cond), m_AllOnes(), m_One())),
m_Value(OtherOp)))) {
bool HasAnyNoWrap = I.hasNoSignedWrap() || I.hasNoUnsignedWrap();
Value *Neg = Builder.CreateNeg(OtherOp, "", false, HasAnyNoWrap);
return Builder.CreateSelect(Cond, Neg, OtherOp);
}
// fmul (select Cond, 1.0, -1.0), OtherOp --> select Cond, OtherOp, -OtherOp
// fmul OtherOp, (select Cond, 1.0, -1.0) --> select Cond, OtherOp, -OtherOp
if (match(&I, m_c_FMul(m_OneUse(m_Select(m_Value(Cond), m_SpecificFP(1.0),
m_SpecificFP(-1.0))),
m_Value(OtherOp)))) {
IRBuilder<>::FastMathFlagGuard FMFGuard(Builder);
Builder.setFastMathFlags(I.getFastMathFlags());
return Builder.CreateSelect(Cond, OtherOp, Builder.CreateFNeg(OtherOp));
}
// fmul (select Cond, -1.0, 1.0), OtherOp --> select Cond, -OtherOp, OtherOp
// fmul OtherOp, (select Cond, -1.0, 1.0) --> select Cond, -OtherOp, OtherOp
if (match(&I, m_c_FMul(m_OneUse(m_Select(m_Value(Cond), m_SpecificFP(-1.0),
m_SpecificFP(1.0))),
m_Value(OtherOp)))) {
IRBuilder<>::FastMathFlagGuard FMFGuard(Builder);
Builder.setFastMathFlags(I.getFastMathFlags());
return Builder.CreateSelect(Cond, Builder.CreateFNeg(OtherOp), OtherOp);
}
return nullptr;
}
Instruction *InstCombinerImpl::visitMul(BinaryOperator &I) {
if (Value *V = simplifyMulInst(I.getOperand(0), I.getOperand(1),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (SimplifyAssociativeOrCommutative(I))
return &I;
if (Instruction *X = foldVectorBinop(I))
return X;
if (Instruction *Phi = foldBinopWithPhiOperands(I))
return Phi;
if (Value *V = SimplifyUsingDistributiveLaws(I))
return replaceInstUsesWith(I, V);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
unsigned BitWidth = I.getType()->getScalarSizeInBits();
// X * -1 == 0 - X
if (match(Op1, m_AllOnes())) {
BinaryOperator *BO = BinaryOperator::CreateNeg(Op0, I.getName());
if (I.hasNoSignedWrap())
BO->setHasNoSignedWrap();
return BO;
}
// Also allow combining multiply instructions on vectors.
{
Value *NewOp;
Constant *C1, *C2;
const APInt *IVal;
if (match(&I, m_Mul(m_Shl(m_Value(NewOp), m_Constant(C2)),
m_Constant(C1))) &&
match(C1, m_APInt(IVal))) {
// ((X << C2)*C1) == (X * (C1 << C2))
Constant *Shl = ConstantExpr::getShl(C1, C2);
BinaryOperator *Mul = cast<BinaryOperator>(I.getOperand(0));
BinaryOperator *BO = BinaryOperator::CreateMul(NewOp, Shl);
if (I.hasNoUnsignedWrap() && Mul->hasNoUnsignedWrap())
BO->setHasNoUnsignedWrap();
if (I.hasNoSignedWrap() && Mul->hasNoSignedWrap() &&
Shl->isNotMinSignedValue())
BO->setHasNoSignedWrap();
return BO;
}
if (match(&I, m_Mul(m_Value(NewOp), m_Constant(C1)))) {
// Replace X*(2^C) with X << C, where C is either a scalar or a vector.
if (Constant *NewCst = ConstantExpr::getExactLogBase2(C1)) {
BinaryOperator *Shl = BinaryOperator::CreateShl(NewOp, NewCst);
if (I.hasNoUnsignedWrap())
Shl->setHasNoUnsignedWrap();
if (I.hasNoSignedWrap()) {
const APInt *V;
if (match(NewCst, m_APInt(V)) && *V != V->getBitWidth() - 1)
Shl->setHasNoSignedWrap();
}
return Shl;
}
}
}
if (Op0->hasOneUse() && match(Op1, m_NegatedPower2())) {
// Interpret X * (-1<<C) as (-X) * (1<<C) and try to sink the negation.
// The "* (1<<C)" thus becomes a potential shifting opportunity.
if (Value *NegOp0 = Negator::Negate(/*IsNegation*/ true, Op0, *this))
return BinaryOperator::CreateMul(
NegOp0, ConstantExpr::getNeg(cast<Constant>(Op1)), I.getName());
}
if (Instruction *FoldedMul = foldBinOpIntoSelectOrPhi(I))
return FoldedMul;
if (Value *FoldedMul = foldMulSelectToNegate(I, Builder))
return replaceInstUsesWith(I, FoldedMul);
// Simplify mul instructions with a constant RHS.
if (isa<Constant>(Op1)) {
// Canonicalize (X+C1)*CI -> X*CI+C1*CI.
Value *X;
Constant *C1;
if (match(Op0, m_OneUse(m_Add(m_Value(X), m_Constant(C1))))) {
Value *Mul = Builder.CreateMul(C1, Op1);
// Only go forward with the transform if C1*CI simplifies to a tidier
// constant.
if (!match(Mul, m_Mul(m_Value(), m_Value())))
return BinaryOperator::CreateAdd(Builder.CreateMul(X, Op1), Mul);
}
}
// abs(X) * abs(X) -> X * X
// nabs(X) * nabs(X) -> X * X
if (Op0 == Op1) {
Value *X, *Y;
SelectPatternFlavor SPF = matchSelectPattern(Op0, X, Y).Flavor;
if (SPF == SPF_ABS || SPF == SPF_NABS)
return BinaryOperator::CreateMul(X, X);
if (match(Op0, m_Intrinsic<Intrinsic::abs>(m_Value(X))))
return BinaryOperator::CreateMul(X, X);
}
// -X * C --> X * -C
Value *X, *Y;
Constant *Op1C;
if (match(Op0, m_Neg(m_Value(X))) && match(Op1, m_Constant(Op1C)))
return BinaryOperator::CreateMul(X, ConstantExpr::getNeg(Op1C));
// -X * -Y --> X * Y
if (match(Op0, m_Neg(m_Value(X))) && match(Op1, m_Neg(m_Value(Y)))) {
auto *NewMul = BinaryOperator::CreateMul(X, Y);
if (I.hasNoSignedWrap() &&
cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap() &&
cast<OverflowingBinaryOperator>(Op1)->hasNoSignedWrap())
NewMul->setHasNoSignedWrap();
return NewMul;
}
// -X * Y --> -(X * Y)
// X * -Y --> -(X * Y)
if (match(&I, m_c_Mul(m_OneUse(m_Neg(m_Value(X))), m_Value(Y))))
return BinaryOperator::CreateNeg(Builder.CreateMul(X, Y));
// (X / Y) * Y = X - (X % Y)
// (X / Y) * -Y = (X % Y) - X
{
Value *Y = Op1;
BinaryOperator *Div = dyn_cast<BinaryOperator>(Op0);
if (!Div || (Div->getOpcode() != Instruction::UDiv &&
Div->getOpcode() != Instruction::SDiv)) {
Y = Op0;
Div = dyn_cast<BinaryOperator>(Op1);
}
Value *Neg = dyn_castNegVal(Y);
if (Div && Div->hasOneUse() &&
(Div->getOperand(1) == Y || Div->getOperand(1) == Neg) &&
(Div->getOpcode() == Instruction::UDiv ||
Div->getOpcode() == Instruction::SDiv)) {
Value *X = Div->getOperand(0), *DivOp1 = Div->getOperand(1);
// If the division is exact, X % Y is zero, so we end up with X or -X.
if (Div->isExact()) {
if (DivOp1 == Y)
return replaceInstUsesWith(I, X);
return BinaryOperator::CreateNeg(X);
}
auto RemOpc = Div->getOpcode() == Instruction::UDiv ? Instruction::URem
: Instruction::SRem;
// X must be frozen because we are increasing its number of uses.
Value *XFreeze = Builder.CreateFreeze(X, X->getName() + ".fr");
Value *Rem = Builder.CreateBinOp(RemOpc, XFreeze, DivOp1);
if (DivOp1 == Y)
return BinaryOperator::CreateSub(XFreeze, Rem);
return BinaryOperator::CreateSub(Rem, XFreeze);
}
}
// Fold the following two scenarios:
// 1) i1 mul -> i1 and.
// 2) X * Y --> X & Y, iff X, Y can be only {0,1}.
// Note: We could use known bits to generalize this and related patterns with
// shifts/truncs
Type *Ty = I.getType();
if (Ty->isIntOrIntVectorTy(1) ||
(match(Op0, m_And(m_Value(), m_One())) &&
match(Op1, m_And(m_Value(), m_One()))))
return BinaryOperator::CreateAnd(Op0, Op1);
// X*(1 << Y) --> X << Y
// (1 << Y)*X --> X << Y
{
Value *Y;
BinaryOperator *BO = nullptr;
bool ShlNSW = false;
if (match(Op0, m_Shl(m_One(), m_Value(Y)))) {
BO = BinaryOperator::CreateShl(Op1, Y);
ShlNSW = cast<ShlOperator>(Op0)->hasNoSignedWrap();
} else if (match(Op1, m_Shl(m_One(), m_Value(Y)))) {
BO = BinaryOperator::CreateShl(Op0, Y);
ShlNSW = cast<ShlOperator>(Op1)->hasNoSignedWrap();
}
if (BO) {
if (I.hasNoUnsignedWrap())
BO->setHasNoUnsignedWrap();
if (I.hasNoSignedWrap() && ShlNSW)
BO->setHasNoSignedWrap();
return BO;
}
}
// (zext bool X) * (zext bool Y) --> zext (and X, Y)
// (sext bool X) * (sext bool Y) --> zext (and X, Y)
// Note: -1 * -1 == 1 * 1 == 1 (if the extends match, the result is the same)
if (((match(Op0, m_ZExt(m_Value(X))) && match(Op1, m_ZExt(m_Value(Y)))) ||
(match(Op0, m_SExt(m_Value(X))) && match(Op1, m_SExt(m_Value(Y))))) &&
X->getType()->isIntOrIntVectorTy(1) && X->getType() == Y->getType() &&
(Op0->hasOneUse() || Op1->hasOneUse() || X == Y)) {
Value *And = Builder.CreateAnd(X, Y, "mulbool");
return CastInst::Create(Instruction::ZExt, And, Ty);
}
// (sext bool X) * (zext bool Y) --> sext (and X, Y)
// (zext bool X) * (sext bool Y) --> sext (and X, Y)
// Note: -1 * 1 == 1 * -1 == -1
if (((match(Op0, m_SExt(m_Value(X))) && match(Op1, m_ZExt(m_Value(Y)))) ||
(match(Op0, m_ZExt(m_Value(X))) && match(Op1, m_SExt(m_Value(Y))))) &&
X->getType()->isIntOrIntVectorTy(1) && X->getType() == Y->getType() &&
(Op0->hasOneUse() || Op1->hasOneUse())) {
Value *And = Builder.CreateAnd(X, Y, "mulbool");
return CastInst::Create(Instruction::SExt, And, Ty);
}
// (zext bool X) * Y --> X ? Y : 0
// Y * (zext bool X) --> X ? Y : 0
if (match(Op0, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))
return SelectInst::Create(X, Op1, ConstantInt::getNullValue(Ty));
if (match(Op1, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))
return SelectInst::Create(X, Op0, ConstantInt::getNullValue(Ty));
Constant *ImmC;
if (match(Op1, m_ImmConstant(ImmC))) {
// (sext bool X) * C --> X ? -C : 0
if (match(Op0, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) {
Constant *NegC = ConstantExpr::getNeg(ImmC);
return SelectInst::Create(X, NegC, ConstantInt::getNullValue(Ty));
}
// (ashr i32 X, 31) * C --> (X < 0) ? -C : 0
const APInt *C;
if (match(Op0, m_OneUse(m_AShr(m_Value(X), m_APInt(C)))) &&
*C == C->getBitWidth() - 1) {
Constant *NegC = ConstantExpr::getNeg(ImmC);
Value *IsNeg = Builder.CreateIsNeg(X, "isneg");
return SelectInst::Create(IsNeg, NegC, ConstantInt::getNullValue(Ty));
}
}
// (lshr X, 31) * Y --> (X < 0) ? Y : 0
// TODO: We are not checking one-use because the elimination of the multiply
// is better for analysis?
const APInt *C;
if (match(&I, m_c_BinOp(m_LShr(m_Value(X), m_APInt(C)), m_Value(Y))) &&
*C == C->getBitWidth() - 1) {
Value *IsNeg = Builder.CreateIsNeg(X, "isneg");
return SelectInst::Create(IsNeg, Y, ConstantInt::getNullValue(Ty));
}
// (and X, 1) * Y --> (trunc X) ? Y : 0
if (match(&I, m_c_BinOp(m_OneUse(m_And(m_Value(X), m_One())), m_Value(Y)))) {
Value *Tr = Builder.CreateTrunc(X, CmpInst::makeCmpResultType(Ty));
return SelectInst::Create(Tr, Y, ConstantInt::getNullValue(Ty));
}
// ((ashr X, 31) | 1) * X --> abs(X)
// X * ((ashr X, 31) | 1) --> abs(X)
if (match(&I, m_c_BinOp(m_Or(m_AShr(m_Value(X),
m_SpecificIntAllowUndef(BitWidth - 1)),
m_One()),
m_Deferred(X)))) {
Value *Abs = Builder.CreateBinaryIntrinsic(
Intrinsic::abs, X,
ConstantInt::getBool(I.getContext(), I.hasNoSignedWrap()));
Abs->takeName(&I);
return replaceInstUsesWith(I, Abs);
}
if (Instruction *Ext = narrowMathIfNoOverflow(I))
return Ext;
bool Changed = false;
if (!I.hasNoSignedWrap() && willNotOverflowSignedMul(Op0, Op1, I)) {
Changed = true;
I.setHasNoSignedWrap(true);
}
if (!I.hasNoUnsignedWrap() && willNotOverflowUnsignedMul(Op0, Op1, I)) {
Changed = true;
I.setHasNoUnsignedWrap(true);
}
return Changed ? &I : nullptr;
}
Instruction *InstCombinerImpl::foldFPSignBitOps(BinaryOperator &I) {
BinaryOperator::BinaryOps Opcode = I.getOpcode();
assert((Opcode == Instruction::FMul || Opcode == Instruction::FDiv) &&
"Expected fmul or fdiv");
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Value *X, *Y;
// -X * -Y --> X * Y
// -X / -Y --> X / Y
if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_FNeg(m_Value(Y))))
return BinaryOperator::CreateWithCopiedFlags(Opcode, X, Y, &I);
// fabs(X) * fabs(X) -> X * X
// fabs(X) / fabs(X) -> X / X
if (Op0 == Op1 && match(Op0, m_FAbs(m_Value(X))))
return BinaryOperator::CreateWithCopiedFlags(Opcode, X, X, &I);
// fabs(X) * fabs(Y) --> fabs(X * Y)
// fabs(X) / fabs(Y) --> fabs(X / Y)
if (match(Op0, m_FAbs(m_Value(X))) && match(Op1, m_FAbs(m_Value(Y))) &&
(Op0->hasOneUse() || Op1->hasOneUse())) {
IRBuilder<>::FastMathFlagGuard FMFGuard(Builder);
Builder.setFastMathFlags(I.getFastMathFlags());
Value *XY = Builder.CreateBinOp(Opcode, X, Y);
Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, XY);
Fabs->takeName(&I);
return replaceInstUsesWith(I, Fabs);
}
return nullptr;
}
Instruction *InstCombinerImpl::visitFMul(BinaryOperator &I) {
if (Value *V = simplifyFMulInst(I.getOperand(0), I.getOperand(1),
I.getFastMathFlags(),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (SimplifyAssociativeOrCommutative(I))
return &I;
if (Instruction *X = foldVectorBinop(I))
return X;
if (Instruction *Phi = foldBinopWithPhiOperands(I))
return Phi;
if (Instruction *FoldedMul = foldBinOpIntoSelectOrPhi(I))
return FoldedMul;
if (Value *FoldedMul = foldMulSelectToNegate(I, Builder))
return replaceInstUsesWith(I, FoldedMul);
if (Instruction *R = foldFPSignBitOps(I))
return R;
// X * -1.0 --> -X
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
if (match(Op1, m_SpecificFP(-1.0)))
return UnaryOperator::CreateFNegFMF(Op0, &I);
// -X * C --> X * -C
Value *X, *Y;
Constant *C;
if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_Constant(C)))
return BinaryOperator::CreateFMulFMF(X, ConstantExpr::getFNeg(C), &I);
// (select A, B, C) * (select A, D, E) --> select A, (B*D), (C*E)
if (Value *V = SimplifySelectsFeedingBinaryOp(I, Op0, Op1))
return replaceInstUsesWith(I, V);
if (I.hasAllowReassoc()) {
// Reassociate constant RHS with another constant to form constant
// expression.
if (match(Op1, m_Constant(C)) && C->isFiniteNonZeroFP()) {
Constant *C1;
if (match(Op0, m_OneUse(m_FDiv(m_Constant(C1), m_Value(X))))) {
// (C1 / X) * C --> (C * C1) / X
Constant *CC1 =
ConstantFoldBinaryOpOperands(Instruction::FMul, C, C1, DL);
if (CC1 && CC1->isNormalFP())
return BinaryOperator::CreateFDivFMF(CC1, X, &I);
}
if (match(Op0, m_FDiv(m_Value(X), m_Constant(C1)))) {
// (X / C1) * C --> X * (C / C1)
Constant *CDivC1 =
ConstantFoldBinaryOpOperands(Instruction::FDiv, C, C1, DL);
if (CDivC1 && CDivC1->isNormalFP())
return BinaryOperator::CreateFMulFMF(X, CDivC1, &I);
// If the constant was a denormal, try reassociating differently.
// (X / C1) * C --> X / (C1 / C)
Constant *C1DivC =
ConstantFoldBinaryOpOperands(Instruction::FDiv, C1, C, DL);
if (C1DivC && Op0->hasOneUse() && C1DivC->isNormalFP())
return BinaryOperator::CreateFDivFMF(X, C1DivC, &I);
}
// We do not need to match 'fadd C, X' and 'fsub X, C' because they are
// canonicalized to 'fadd X, C'. Distributing the multiply may allow
// further folds and (X * C) + C2 is 'fma'.
if (match(Op0, m_OneUse(m_FAdd(m_Value(X), m_Constant(C1))))) {
// (X + C1) * C --> (X * C) + (C * C1)
if (Constant *CC1 = ConstantFoldBinaryOpOperands(
Instruction::FMul, C, C1, DL)) {
Value *XC = Builder.CreateFMulFMF(X, C, &I);
return BinaryOperator::CreateFAddFMF(XC, CC1, &I);
}
}
if (match(Op0, m_OneUse(m_FSub(m_Constant(C1), m_Value(X))))) {
// (C1 - X) * C --> (C * C1) - (X * C)
if (Constant *CC1 = ConstantFoldBinaryOpOperands(
Instruction::FMul, C, C1, DL)) {
Value *XC = Builder.CreateFMulFMF(X, C, &I);
return BinaryOperator::CreateFSubFMF(CC1, XC, &I);
}
}
}
Value *Z;
if (match(&I, m_c_FMul(m_OneUse(m_FDiv(m_Value(X), m_Value(Y))),
m_Value(Z)))) {
// Sink division: (X / Y) * Z --> (X * Z) / Y
Value *NewFMul = Builder.CreateFMulFMF(X, Z, &I);
return BinaryOperator::CreateFDivFMF(NewFMul, Y, &I);
}
// sqrt(X) * sqrt(Y) -> sqrt(X * Y)
// nnan disallows the possibility of returning a number if both operands are
// negative (in that case, we should return NaN).
if (I.hasNoNaNs() && match(Op0, m_OneUse(m_Sqrt(m_Value(X)))) &&
match(Op1, m_OneUse(m_Sqrt(m_Value(Y))))) {
Value *XY = Builder.CreateFMulFMF(X, Y, &I);
Value *Sqrt = Builder.CreateUnaryIntrinsic(Intrinsic::sqrt, XY, &I);
return replaceInstUsesWith(I, Sqrt);
}
// The following transforms are done irrespective of the number of uses
// for the expression "1.0/sqrt(X)".
// 1) 1.0/sqrt(X) * X -> X/sqrt(X)
// 2) X * 1.0/sqrt(X) -> X/sqrt(X)
// We always expect the backend to reduce X/sqrt(X) to sqrt(X), if it
// has the necessary (reassoc) fast-math-flags.
if (I.hasNoSignedZeros() &&
match(Op0, (m_FDiv(m_SpecificFP(1.0), m_Value(Y)))) &&
match(Y, m_Sqrt(m_Value(X))) && Op1 == X)
return BinaryOperator::CreateFDivFMF(X, Y, &I);
if (I.hasNoSignedZeros() &&
match(Op1, (m_FDiv(m_SpecificFP(1.0), m_Value(Y)))) &&
match(Y, m_Sqrt(m_Value(X))) && Op0 == X)
return BinaryOperator::CreateFDivFMF(X, Y, &I);
// Like the similar transform in instsimplify, this requires 'nsz' because
// sqrt(-0.0) = -0.0, and -0.0 * -0.0 does not simplify to -0.0.
if (I.hasNoNaNs() && I.hasNoSignedZeros() && Op0 == Op1 &&
Op0->hasNUses(2)) {
// Peek through fdiv to find squaring of square root:
// (X / sqrt(Y)) * (X / sqrt(Y)) --> (X * X) / Y
if (match(Op0, m_FDiv(m_Value(X), m_Sqrt(m_Value(Y))))) {
Value *XX = Builder.CreateFMulFMF(X, X, &I);
return BinaryOperator::CreateFDivFMF(XX, Y, &I);
}
// (sqrt(Y) / X) * (sqrt(Y) / X) --> Y / (X * X)
if (match(Op0, m_FDiv(m_Sqrt(m_Value(Y)), m_Value(X)))) {
Value *XX = Builder.CreateFMulFMF(X, X, &I);
return BinaryOperator::CreateFDivFMF(Y, XX, &I);
}
}
if (I.isOnlyUserOfAnyOperand()) {
// pow(x, y) * pow(x, z) -> pow(x, y + z)
if (match(Op0, m_Intrinsic<Intrinsic::pow>(m_Value(X), m_Value(Y))) &&
match(Op1, m_Intrinsic<Intrinsic::pow>(m_Specific(X), m_Value(Z)))) {
auto *YZ = Builder.CreateFAddFMF(Y, Z, &I);
auto *NewPow = Builder.CreateBinaryIntrinsic(Intrinsic::pow, X, YZ, &I);
return replaceInstUsesWith(I, NewPow);
}
// powi(x, y) * powi(x, z) -> powi(x, y + z)
if (match(Op0, m_Intrinsic<Intrinsic::powi>(m_Value(X), m_Value(Y))) &&
match(Op1, m_Intrinsic<Intrinsic::powi>(m_Specific(X), m_Value(Z))) &&
Y->getType() == Z->getType()) {
auto *YZ = Builder.CreateAdd(Y, Z);
auto *NewPow = Builder.CreateIntrinsic(
Intrinsic::powi, {X->getType(), YZ->getType()}, {X, YZ}, &I);
return replaceInstUsesWith(I, NewPow);
}
// exp(X) * exp(Y) -> exp(X + Y)
if (match(Op0, m_Intrinsic<Intrinsic::exp>(m_Value(X))) &&
match(Op1, m_Intrinsic<Intrinsic::exp>(m_Value(Y)))) {
Value *XY = Builder.CreateFAddFMF(X, Y, &I);
Value *Exp = Builder.CreateUnaryIntrinsic(Intrinsic::exp, XY, &I);
return replaceInstUsesWith(I, Exp);
}
// exp2(X) * exp2(Y) -> exp2(X + Y)
if (match(Op0, m_Intrinsic<Intrinsic::exp2>(m_Value(X))) &&
match(Op1, m_Intrinsic<Intrinsic::exp2>(m_Value(Y)))) {
Value *XY = Builder.CreateFAddFMF(X, Y, &I);
Value *Exp2 = Builder.CreateUnaryIntrinsic(Intrinsic::exp2, XY, &I);
return replaceInstUsesWith(I, Exp2);
}
}
// (X*Y) * X => (X*X) * Y where Y != X
// The purpose is two-fold:
// 1) to form a power expression (of X).
// 2) potentially shorten the critical path: After transformation, the
// latency of the instruction Y is amortized by the expression of X*X,
// and therefore Y is in a "less critical" position compared to what it
// was before the transformation.
if (match(Op0, m_OneUse(m_c_FMul(m_Specific(Op1), m_Value(Y)))) &&
Op1 != Y) {
Value *XX = Builder.CreateFMulFMF(Op1, Op1, &I);
return BinaryOperator::CreateFMulFMF(XX, Y, &I);
}
if (match(Op1, m_OneUse(m_c_FMul(m_Specific(Op0), m_Value(Y)))) &&
Op0 != Y) {
Value *XX = Builder.CreateFMulFMF(Op0, Op0, &I);
return BinaryOperator::CreateFMulFMF(XX, Y, &I);
}
}
// log2(X * 0.5) * Y = log2(X) * Y - Y
if (I.isFast()) {
IntrinsicInst *Log2 = nullptr;
if (match(Op0, m_OneUse(m_Intrinsic<Intrinsic::log2>(
m_OneUse(m_FMul(m_Value(X), m_SpecificFP(0.5))))))) {
Log2 = cast<IntrinsicInst>(Op0);
Y = Op1;
}
if (match(Op1, m_OneUse(m_Intrinsic<Intrinsic::log2>(
m_OneUse(m_FMul(m_Value(X), m_SpecificFP(0.5))))))) {
Log2 = cast<IntrinsicInst>(Op1);
Y = Op0;
}
if (Log2) {
Value *Log2 = Builder.CreateUnaryIntrinsic(Intrinsic::log2, X, &I);
Value *LogXTimesY = Builder.CreateFMulFMF(Log2, Y, &I);
return BinaryOperator::CreateFSubFMF(LogXTimesY, Y, &I);
}
}
return nullptr;
}
/// Fold a divide or remainder with a select instruction divisor when one of the
/// select operands is zero. In that case, we can use the other select operand
/// because div/rem by zero is undefined.
bool InstCombinerImpl::simplifyDivRemOfSelectWithZeroOp(BinaryOperator &I) {
SelectInst *SI = dyn_cast<SelectInst>(I.getOperand(1));
if (!SI)
return false;
int NonNullOperand;
if (match(SI->getTrueValue(), m_Zero()))
// div/rem X, (Cond ? 0 : Y) -> div/rem X, Y
NonNullOperand = 2;
else if (match(SI->getFalseValue(), m_Zero()))
// div/rem X, (Cond ? Y : 0) -> div/rem X, Y
NonNullOperand = 1;
else
return false;
// Change the div/rem to use 'Y' instead of the select.
replaceOperand(I, 1, SI->getOperand(NonNullOperand));
// Okay, we know we replace the operand of the div/rem with 'Y' with no
// problem. However, the select, or the condition of the select may have
// multiple uses. Based on our knowledge that the operand must be non-zero,
// propagate the known value for the select into other uses of it, and
// propagate a known value of the condition into its other users.
// If the select and condition only have a single use, don't bother with this,
// early exit.
Value *SelectCond = SI->getCondition();
if (SI->use_empty() && SelectCond->hasOneUse())
return true;
// Scan the current block backward, looking for other uses of SI.
BasicBlock::iterator BBI = I.getIterator(), BBFront = I.getParent()->begin();
Type *CondTy = SelectCond->getType();
while (BBI != BBFront) {
--BBI;
// If we found an instruction that we can't assume will return, so
// information from below it cannot be propagated above it.
if (!isGuaranteedToTransferExecutionToSuccessor(&*BBI))
break;
// Replace uses of the select or its condition with the known values.
for (Use &Op : BBI->operands()) {
if (Op == SI) {
replaceUse(Op, SI->getOperand(NonNullOperand));
Worklist.push(&*BBI);
} else if (Op == SelectCond) {
replaceUse(Op, NonNullOperand == 1 ? ConstantInt::getTrue(CondTy)
: ConstantInt::getFalse(CondTy));
Worklist.push(&*BBI);
}
}
// If we past the instruction, quit looking for it.
if (&*BBI == SI)
SI = nullptr;
if (&*BBI == SelectCond)
SelectCond = nullptr;
// If we ran out of things to eliminate, break out of the loop.
if (!SelectCond && !SI)
break;
}
return true;
}
/// True if the multiply can not be expressed in an int this size.
static bool multiplyOverflows(const APInt &C1, const APInt &C2, APInt &Product,
bool IsSigned) {
bool Overflow;
Product = IsSigned ? C1.smul_ov(C2, Overflow) : C1.umul_ov(C2, Overflow);
return Overflow;
}
/// True if C1 is a multiple of C2. Quotient contains C1/C2.
static bool isMultiple(const APInt &C1, const APInt &C2, APInt &Quotient,
bool IsSigned) {
assert(C1.getBitWidth() == C2.getBitWidth() && "Constant widths not equal");
// Bail if we will divide by zero.
if (C2.isZero())
return false;
// Bail if we would divide INT_MIN by -1.
if (IsSigned && C1.isMinSignedValue() && C2.isAllOnes())
return false;
APInt Remainder(C1.getBitWidth(), /*val=*/0ULL, IsSigned);
if (IsSigned)
APInt::sdivrem(C1, C2, Quotient, Remainder);
else
APInt::udivrem(C1, C2, Quotient, Remainder);
return Remainder.isMinValue();
}
/// This function implements the transforms common to both integer division
/// instructions (udiv and sdiv). It is called by the visitors to those integer
/// division instructions.
/// Common integer divide transforms
Instruction *InstCombinerImpl::commonIDivTransforms(BinaryOperator &I) {
if (Instruction *Phi = foldBinopWithPhiOperands(I))
return Phi;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
bool IsSigned = I.getOpcode() == Instruction::SDiv;
Type *Ty = I.getType();
// The RHS is known non-zero.
if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this, I))
return replaceOperand(I, 1, V);
// Handle cases involving: [su]div X, (select Cond, Y, Z)
// This does not apply for fdiv.
if (simplifyDivRemOfSelectWithZeroOp(I))
return &I;
// If the divisor is a select-of-constants, try to constant fold all div ops:
// C / (select Cond, TrueC, FalseC) --> select Cond, (C / TrueC), (C / FalseC)
// TODO: Adapt simplifyDivRemOfSelectWithZeroOp to allow this and other folds.
if (match(Op0, m_ImmConstant()) &&
match(Op1, m_Select(m_Value(), m_ImmConstant(), m_ImmConstant()))) {
if (Instruction *R = FoldOpIntoSelect(I, cast<SelectInst>(Op1),
/*FoldWithMultiUse*/ true))
return R;
}
const APInt *C2;
if (match(Op1, m_APInt(C2))) {
Value *X;
const APInt *C1;
// (X / C1) / C2 -> X / (C1*C2)
if ((IsSigned && match(Op0, m_SDiv(m_Value(X), m_APInt(C1)))) ||
(!IsSigned && match(Op0, m_UDiv(m_Value(X), m_APInt(C1))))) {
APInt Product(C1->getBitWidth(), /*val=*/0ULL, IsSigned);
if (!multiplyOverflows(*C1, *C2, Product, IsSigned))
return BinaryOperator::Create(I.getOpcode(), X,
ConstantInt::get(Ty, Product));
}
if ((IsSigned && match(Op0, m_NSWMul(m_Value(X), m_APInt(C1)))) ||
(!IsSigned && match(Op0, m_NUWMul(m_Value(X), m_APInt(C1))))) {
APInt Quotient(C1->getBitWidth(), /*val=*/0ULL, IsSigned);
// (X * C1) / C2 -> X / (C2 / C1) if C2 is a multiple of C1.
if (isMultiple(*C2, *C1, Quotient, IsSigned)) {
auto *NewDiv = BinaryOperator::Create(I.getOpcode(), X,
ConstantInt::get(Ty, Quotient));
NewDiv->setIsExact(I.isExact());
return NewDiv;
}
// (X * C1) / C2 -> X * (C1 / C2) if C1 is a multiple of C2.
if (isMultiple(*C1, *C2, Quotient, IsSigned)) {
auto *Mul = BinaryOperator::Create(Instruction::Mul, X,
ConstantInt::get(Ty, Quotient));
auto *OBO = cast<OverflowingBinaryOperator>(Op0);
Mul->setHasNoUnsignedWrap(!IsSigned && OBO->hasNoUnsignedWrap());
Mul->setHasNoSignedWrap(OBO->hasNoSignedWrap());
return Mul;
}
}
if ((IsSigned && match(Op0, m_NSWShl(m_Value(X), m_APInt(C1))) &&
C1->ult(C1->getBitWidth() - 1)) ||
(!IsSigned && match(Op0, m_NUWShl(m_Value(X), m_APInt(C1))) &&
C1->ult(C1->getBitWidth()))) {
APInt Quotient(C1->getBitWidth(), /*val=*/0ULL, IsSigned);
APInt C1Shifted = APInt::getOneBitSet(
C1->getBitWidth(), static_cast<unsigned>(C1->getZExtValue()));
// (X << C1) / C2 -> X / (C2 >> C1) if C2 is a multiple of 1 << C1.
if (isMultiple(*C2, C1Shifted, Quotient, IsSigned)) {
auto *BO = BinaryOperator::Create(I.getOpcode(), X,
ConstantInt::get(Ty, Quotient));
BO->setIsExact(I.isExact());
return BO;
}
// (X << C1) / C2 -> X * ((1 << C1) / C2) if 1 << C1 is a multiple of C2.
if (isMultiple(C1Shifted, *C2, Quotient, IsSigned)) {
auto *Mul = BinaryOperator::Create(Instruction::Mul, X,
ConstantInt::get(Ty, Quotient));
auto *OBO = cast<OverflowingBinaryOperator>(Op0);
Mul->setHasNoUnsignedWrap(!IsSigned && OBO->hasNoUnsignedWrap());
Mul->setHasNoSignedWrap(OBO->hasNoSignedWrap());
return Mul;
}
}
if (!C2->isZero()) // avoid X udiv 0
if (Instruction *FoldedDiv = foldBinOpIntoSelectOrPhi(I))
return FoldedDiv;
}
if (match(Op0, m_One())) {
assert(!Ty->isIntOrIntVectorTy(1) && "i1 divide not removed?");
if (IsSigned) {
// 1 / 0 --> undef ; 1 / 1 --> 1 ; 1 / -1 --> -1 ; 1 / anything else --> 0
// (Op1 + 1) u< 3 ? Op1 : 0
// Op1 must be frozen because we are increasing its number of uses.
Value *F1 = Builder.CreateFreeze(Op1, Op1->getName() + ".fr");
Value *Inc = Builder.CreateAdd(F1, Op0);
Value *Cmp = Builder.CreateICmpULT(Inc, ConstantInt::get(Ty, 3));
return SelectInst::Create(Cmp, F1, ConstantInt::get(Ty, 0));
} else {
// If Op1 is 0 then it's undefined behaviour. If Op1 is 1 then the
// result is one, otherwise it's zero.
return new ZExtInst(Builder.CreateICmpEQ(Op1, Op0), Ty);
}
}
// See if we can fold away this div instruction.
if (SimplifyDemandedInstructionBits(I))
return &I;
// (X - (X rem Y)) / Y -> X / Y; usually originates as ((X / Y) * Y) / Y
Value *X, *Z;
if (match(Op0, m_Sub(m_Value(X), m_Value(Z)))) // (X - Z) / Y; Y = Op1
if ((IsSigned && match(Z, m_SRem(m_Specific(X), m_Specific(Op1)))) ||
(!IsSigned && match(Z, m_URem(m_Specific(X), m_Specific(Op1)))))
return BinaryOperator::Create(I.getOpcode(), X, Op1);
// (X << Y) / X -> 1 << Y
Value *Y;
if (IsSigned && match(Op0, m_NSWShl(m_Specific(Op1), m_Value(Y))))
return BinaryOperator::CreateNSWShl(ConstantInt::get(Ty, 1), Y);
if (!IsSigned && match(Op0, m_NUWShl(m_Specific(Op1), m_Value(Y))))
return BinaryOperator::CreateNUWShl(ConstantInt::get(Ty, 1), Y);
// X / (X * Y) -> 1 / Y if the multiplication does not overflow.
if (match(Op1, m_c_Mul(m_Specific(Op0), m_Value(Y)))) {
bool HasNSW = cast<OverflowingBinaryOperator>(Op1)->hasNoSignedWrap();
bool HasNUW = cast<OverflowingBinaryOperator>(Op1)->hasNoUnsignedWrap();
if ((IsSigned && HasNSW) || (!IsSigned && HasNUW)) {
replaceOperand(I, 0, ConstantInt::get(Ty, 1));
replaceOperand(I, 1, Y);
return &I;
}
}
return nullptr;
}
static const unsigned MaxDepth = 6;
// Take the exact integer log2 of the value. If DoFold is true, create the
// actual instructions, otherwise return a non-null dummy value. Return nullptr
// on failure.
static Value *takeLog2(IRBuilderBase &Builder, Value *Op, unsigned Depth,
bool DoFold) {
auto IfFold = [DoFold](function_ref<Value *()> Fn) {
if (!DoFold)
return reinterpret_cast<Value *>(-1);
return Fn();
};
// FIXME: assert that Op1 isn't/doesn't contain undef.
// log2(2^C) -> C
if (match(Op, m_Power2()))
return IfFold([&]() {
Constant *C = ConstantExpr::getExactLogBase2(cast<Constant>(Op));
if (!C)
llvm_unreachable("Failed to constant fold udiv -> logbase2");
return C;
});
// The remaining tests are all recursive, so bail out if we hit the limit.
if (Depth++ == MaxDepth)
return nullptr;
// log2(zext X) -> zext log2(X)
// FIXME: Require one use?
Value *X, *Y;
if (match(Op, m_ZExt(m_Value(X))))
if (Value *LogX = takeLog2(Builder, X, Depth, DoFold))
return IfFold([&]() { return Builder.CreateZExt(LogX, Op->getType()); });
// log2(X << Y) -> log2(X) + Y
// FIXME: Require one use unless X is 1?
if (match(Op, m_Shl(m_Value(X), m_Value(Y))))
if (Value *LogX = takeLog2(Builder, X, Depth, DoFold))
return IfFold([&]() { return Builder.CreateAdd(LogX, Y); });
// log2(Cond ? X : Y) -> Cond ? log2(X) : log2(Y)
// FIXME: missed optimization: if one of the hands of select is/contains
// undef, just directly pick the other one.
// FIXME: can both hands contain undef?
// FIXME: Require one use?
if (SelectInst *SI = dyn_cast<SelectInst>(Op))
if (Value *LogX = takeLog2(Builder, SI->getOperand(1), Depth, DoFold))
if (Value *LogY = takeLog2(Builder, SI->getOperand(2), Depth, DoFold))
return IfFold([&]() {
return Builder.CreateSelect(SI->getOperand(0), LogX, LogY);
});
// log2(umin(X, Y)) -> umin(log2(X), log2(Y))
// log2(umax(X, Y)) -> umax(log2(X), log2(Y))
auto *MinMax = dyn_cast<MinMaxIntrinsic>(Op);
if (MinMax && MinMax->hasOneUse() && !MinMax->isSigned())
if (Value *LogX = takeLog2(Builder, MinMax->getLHS(), Depth, DoFold))
if (Value *LogY = takeLog2(Builder, MinMax->getRHS(), Depth, DoFold))
return IfFold([&]() {
return Builder.CreateBinaryIntrinsic(
MinMax->getIntrinsicID(), LogX, LogY);
});
return nullptr;
}
/// If we have zero-extended operands of an unsigned div or rem, we may be able
/// to narrow the operation (sink the zext below the math).
static Instruction *narrowUDivURem(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
Instruction::BinaryOps Opcode = I.getOpcode();
Value *N = I.getOperand(0);
Value *D = I.getOperand(1);
Type *Ty = I.getType();
Value *X, *Y;
if (match(N, m_ZExt(m_Value(X))) && match(D, m_ZExt(m_Value(Y))) &&
X->getType() == Y->getType() && (N->hasOneUse() || D->hasOneUse())) {
// udiv (zext X), (zext Y) --> zext (udiv X, Y)
// urem (zext X), (zext Y) --> zext (urem X, Y)
Value *NarrowOp = Builder.CreateBinOp(Opcode, X, Y);
return new ZExtInst(NarrowOp, Ty);
}
Constant *C;
if ((match(N, m_OneUse(m_ZExt(m_Value(X)))) && match(D, m_Constant(C))) ||
(match(D, m_OneUse(m_ZExt(m_Value(X)))) && match(N, m_Constant(C)))) {
// If the constant is the same in the smaller type, use the narrow version.
Constant *TruncC = ConstantExpr::getTrunc(C, X->getType());
if (ConstantExpr::getZExt(TruncC, Ty) != C)
return nullptr;
// udiv (zext X), C --> zext (udiv X, C')
// urem (zext X), C --> zext (urem X, C')
// udiv C, (zext X) --> zext (udiv C', X)
// urem C, (zext X) --> zext (urem C', X)
Value *NarrowOp = isa<Constant>(D) ? Builder.CreateBinOp(Opcode, X, TruncC)
: Builder.CreateBinOp(Opcode, TruncC, X);
return new ZExtInst(NarrowOp, Ty);
}
return nullptr;
}
Instruction *InstCombinerImpl::visitUDiv(BinaryOperator &I) {
if (Value *V = simplifyUDivInst(I.getOperand(0), I.getOperand(1),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (Instruction *X = foldVectorBinop(I))
return X;
// Handle the integer div common cases
if (Instruction *Common = commonIDivTransforms(I))
return Common;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Value *X;
const APInt *C1, *C2;
if (match(Op0, m_LShr(m_Value(X), m_APInt(C1))) && match(Op1, m_APInt(C2))) {
// (X lshr C1) udiv C2 --> X udiv (C2 << C1)
bool Overflow;
APInt C2ShlC1 = C2->ushl_ov(*C1, Overflow);
if (!Overflow) {
bool IsExact = I.isExact() && match(Op0, m_Exact(m_Value()));
BinaryOperator *BO = BinaryOperator::CreateUDiv(
X, ConstantInt::get(X->getType(), C2ShlC1));
if (IsExact)
BO->setIsExact();
return BO;
}
}
// Op0 / C where C is large (negative) --> zext (Op0 >= C)
// TODO: Could use isKnownNegative() to handle non-constant values.
Type *Ty = I.getType();
if (match(Op1, m_Negative())) {
Value *Cmp = Builder.CreateICmpUGE(Op0, Op1);
return CastInst::CreateZExtOrBitCast(Cmp, Ty);
}
// Op0 / (sext i1 X) --> zext (Op0 == -1) (if X is 0, the div is undefined)
if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) {
Value *Cmp = Builder.CreateICmpEQ(Op0, ConstantInt::getAllOnesValue(Ty));
return CastInst::CreateZExtOrBitCast(Cmp, Ty);
}
if (Instruction *NarrowDiv = narrowUDivURem(I, Builder))
return NarrowDiv;
// If the udiv operands are non-overflowing multiplies with a common operand,
// then eliminate the common factor:
// (A * B) / (A * X) --> B / X (and commuted variants)
// TODO: The code would be reduced if we had m_c_NUWMul pattern matching.
// TODO: If -reassociation handled this generally, we could remove this.
Value *A, *B;
if (match(Op0, m_NUWMul(m_Value(A), m_Value(B)))) {
if (match(Op1, m_NUWMul(m_Specific(A), m_Value(X))) ||
match(Op1, m_NUWMul(m_Value(X), m_Specific(A))))
return BinaryOperator::CreateUDiv(B, X);
if (match(Op1, m_NUWMul(m_Specific(B), m_Value(X))) ||
match(Op1, m_NUWMul(m_Value(X), m_Specific(B))))
return BinaryOperator::CreateUDiv(A, X);
}
// Op1 udiv Op2 -> Op1 lshr log2(Op2), if log2() folds away.
if (takeLog2(Builder, Op1, /*Depth*/0, /*DoFold*/false)) {
Value *Res = takeLog2(Builder, Op1, /*Depth*/0, /*DoFold*/true);
return replaceInstUsesWith(
I, Builder.CreateLShr(Op0, Res, I.getName(), I.isExact()));
}
return nullptr;
}
Instruction *InstCombinerImpl::visitSDiv(BinaryOperator &I) {
if (Value *V = simplifySDivInst(I.getOperand(0), I.getOperand(1),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (Instruction *X = foldVectorBinop(I))
return X;
// Handle the integer div common cases
if (Instruction *Common = commonIDivTransforms(I))
return Common;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Type *Ty = I.getType();
Value *X;
// sdiv Op0, -1 --> -Op0
// sdiv Op0, (sext i1 X) --> -Op0 (because if X is 0, the op is undefined)
if (match(Op1, m_AllOnes()) ||
(match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
return BinaryOperator::CreateNeg(Op0);
// X / INT_MIN --> X == INT_MIN
if (match(Op1, m_SignMask()))
return new ZExtInst(Builder.CreateICmpEQ(Op0, Op1), Ty);
// sdiv exact X, 1<<C --> ashr exact X, C iff 1<<C is non-negative
// sdiv exact X, -1<<C --> -(ashr exact X, C)
if (I.isExact() && ((match(Op1, m_Power2()) && match(Op1, m_NonNegative())) ||
match(Op1, m_NegatedPower2()))) {
bool DivisorWasNegative = match(Op1, m_NegatedPower2());
if (DivisorWasNegative)
Op1 = ConstantExpr::getNeg(cast<Constant>(Op1));
auto *AShr = BinaryOperator::CreateExactAShr(
Op0, ConstantExpr::getExactLogBase2(cast<Constant>(Op1)), I.getName());
if (!DivisorWasNegative)
return AShr;
Builder.Insert(AShr);
AShr->setName(I.getName() + ".neg");
return BinaryOperator::CreateNeg(AShr, I.getName());
}
const APInt *Op1C;
if (match(Op1, m_APInt(Op1C))) {
// If the dividend is sign-extended and the constant divisor is small enough
// to fit in the source type, shrink the division to the narrower type:
// (sext X) sdiv C --> sext (X sdiv C)
Value *Op0Src;
if (match(Op0, m_OneUse(m_SExt(m_Value(Op0Src)))) &&
Op0Src->getType()->getScalarSizeInBits() >= Op1C->getMinSignedBits()) {
// In the general case, we need to make sure that the dividend is not the
// minimum signed value because dividing that by -1 is UB. But here, we
// know that the -1 divisor case is already handled above.
Constant *NarrowDivisor =
ConstantExpr::getTrunc(cast<Constant>(Op1), Op0Src->getType());
Value *NarrowOp = Builder.CreateSDiv(Op0Src, NarrowDivisor);
return new SExtInst(NarrowOp, Ty);
}
// -X / C --> X / -C (if the negation doesn't overflow).
// TODO: This could be enhanced to handle arbitrary vector constants by
// checking if all elements are not the min-signed-val.
if (!Op1C->isMinSignedValue() &&
match(Op0, m_NSWSub(m_Zero(), m_Value(X)))) {
Constant *NegC = ConstantInt::get(Ty, -(*Op1C));
Instruction *BO = BinaryOperator::CreateSDiv(X, NegC);
BO->setIsExact(I.isExact());
return BO;
}
}
// -X / Y --> -(X / Y)
Value *Y;
if (match(&I, m_SDiv(m_OneUse(m_NSWSub(m_Zero(), m_Value(X))), m_Value(Y))))
return BinaryOperator::CreateNSWNeg(
Builder.CreateSDiv(X, Y, I.getName(), I.isExact()));
// abs(X) / X --> X > -1 ? 1 : -1
// X / abs(X) --> X > -1 ? 1 : -1
if (match(&I, m_c_BinOp(
m_OneUse(m_Intrinsic<Intrinsic::abs>(m_Value(X), m_One())),
m_Deferred(X)))) {
Value *Cond = Builder.CreateIsNotNeg(X);
return SelectInst::Create(Cond, ConstantInt::get(Ty, 1),
ConstantInt::getAllOnesValue(Ty));
}
// If the sign bits of both operands are zero (i.e. we can prove they are
// unsigned inputs), turn this into a udiv.
APInt Mask(APInt::getSignMask(Ty->getScalarSizeInBits()));
if (MaskedValueIsZero(Op0, Mask, 0, &I)) {
if (MaskedValueIsZero(Op1, Mask, 0, &I)) {
// X sdiv Y -> X udiv Y, iff X and Y don't have sign bit set
auto *BO = BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
BO->setIsExact(I.isExact());
return BO;
}
if (match(Op1, m_NegatedPower2())) {
// X sdiv (-(1 << C)) -> -(X sdiv (1 << C)) ->
// -> -(X udiv (1 << C)) -> -(X u>> C)
Constant *CNegLog2 = ConstantExpr::getExactLogBase2(
ConstantExpr::getNeg(cast<Constant>(Op1)));
Value *Shr = Builder.CreateLShr(Op0, CNegLog2, I.getName(), I.isExact());
return BinaryOperator::CreateNeg(Shr);
}
if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/ true, 0, &I)) {
// X sdiv (1 << Y) -> X udiv (1 << Y) ( -> X u>> Y)
// Safe because the only negative value (1 << Y) can take on is
// INT_MIN, and X sdiv INT_MIN == X udiv INT_MIN == 0 if X doesn't have
// the sign bit set.
auto *BO = BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
BO->setIsExact(I.isExact());
return BO;
}
}
return nullptr;
}
/// Remove negation and try to convert division into multiplication.
static Instruction *foldFDivConstantDivisor(BinaryOperator &I) {
Constant *C;
if (!match(I.getOperand(1), m_Constant(C)))
return nullptr;
// -X / C --> X / -C
Value *X;
if (match(I.getOperand(0), m_FNeg(m_Value(X))))
return BinaryOperator::CreateFDivFMF(X, ConstantExpr::getFNeg(C), &I);
// If the constant divisor has an exact inverse, this is always safe. If not,
// then we can still create a reciprocal if fast-math-flags allow it and the
// constant is a regular number (not zero, infinite, or denormal).
if (!(C->hasExactInverseFP() || (I.hasAllowReciprocal() && C->isNormalFP())))
return nullptr;
// Disallow denormal constants because we don't know what would happen
// on all targets.
// TODO: Use Intrinsic::canonicalize or let function attributes tell us that
// denorms are flushed?
const DataLayout &DL = I.getModule()->getDataLayout();
auto *RecipC = ConstantFoldBinaryOpOperands(
Instruction::FDiv, ConstantFP::get(I.getType(), 1.0), C, DL);
if (!RecipC || !RecipC->isNormalFP())
return nullptr;
// X / C --> X * (1 / C)
return BinaryOperator::CreateFMulFMF(I.getOperand(0), RecipC, &I);
}
/// Remove negation and try to reassociate constant math.
static Instruction *foldFDivConstantDividend(BinaryOperator &I) {
Constant *C;
if (!match(I.getOperand(0), m_Constant(C)))
return nullptr;
// C / -X --> -C / X
Value *X;
if (match(I.getOperand(1), m_FNeg(m_Value(X))))
return BinaryOperator::CreateFDivFMF(ConstantExpr::getFNeg(C), X, &I);
if (!I.hasAllowReassoc() || !I.hasAllowReciprocal())
return nullptr;
// Try to reassociate C / X expressions where X includes another constant.
Constant *C2, *NewC = nullptr;
const DataLayout &DL = I.getModule()->getDataLayout();
if (match(I.getOperand(1), m_FMul(m_Value(X), m_Constant(C2)))) {
// C / (X * C2) --> (C / C2) / X
NewC = ConstantFoldBinaryOpOperands(Instruction::FDiv, C, C2, DL);
} else if (match(I.getOperand(1), m_FDiv(m_Value(X), m_Constant(C2)))) {
// C / (X / C2) --> (C * C2) / X
NewC = ConstantFoldBinaryOpOperands(Instruction::FMul, C, C2, DL);
}
// Disallow denormal constants because we don't know what would happen
// on all targets.
// TODO: Use Intrinsic::canonicalize or let function attributes tell us that
// denorms are flushed?
if (!NewC || !NewC->isNormalFP())
return nullptr;
return BinaryOperator::CreateFDivFMF(NewC, X, &I);
}
/// Negate the exponent of pow/exp to fold division-by-pow() into multiply.
static Instruction *foldFDivPowDivisor(BinaryOperator &I,
InstCombiner::BuilderTy &Builder) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
auto *II = dyn_cast<IntrinsicInst>(Op1);
if (!II || !II->hasOneUse() || !I.hasAllowReassoc() ||
!I.hasAllowReciprocal())
return nullptr;
// Z / pow(X, Y) --> Z * pow(X, -Y)
// Z / exp{2}(Y) --> Z * exp{2}(-Y)
// In the general case, this creates an extra instruction, but fmul allows
// for better canonicalization and optimization than fdiv.
Intrinsic::ID IID = II->getIntrinsicID();
SmallVector<Value *> Args;
switch (IID) {
case Intrinsic::pow:
Args.push_back(II->getArgOperand(0));
Args.push_back(Builder.CreateFNegFMF(II->getArgOperand(1), &I));
break;
case Intrinsic::powi: {
// Require 'ninf' assuming that makes powi(X, -INT_MIN) acceptable.
// That is, X ** (huge negative number) is 0.0, ~1.0, or INF and so
// dividing by that is INF, ~1.0, or 0.0. Code that uses powi allows
// non-standard results, so this corner case should be acceptable if the
// code rules out INF values.
if (!I.hasNoInfs())
return nullptr;
Args.push_back(II->getArgOperand(0));
Args.push_back(Builder.CreateNeg(II->getArgOperand(1)));
Type *Tys[] = {I.getType(), II->getArgOperand(1)->getType()};
Value *Pow = Builder.CreateIntrinsic(IID, Tys, Args, &I);
return BinaryOperator::CreateFMulFMF(Op0, Pow, &I);
}
case Intrinsic::exp:
case Intrinsic::exp2:
Args.push_back(Builder.CreateFNegFMF(II->getArgOperand(0), &I));
break;
default:
return nullptr;
}
Value *Pow = Builder.CreateIntrinsic(IID, I.getType(), Args, &I);
return BinaryOperator::CreateFMulFMF(Op0, Pow, &I);
}
Instruction *InstCombinerImpl::visitFDiv(BinaryOperator &I) {
Module *M = I.getModule();
if (Value *V = simplifyFDivInst(I.getOperand(0), I.getOperand(1),
I.getFastMathFlags(),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (Instruction *X = foldVectorBinop(I))
return X;
if (Instruction *Phi = foldBinopWithPhiOperands(I))
return Phi;
if (Instruction *R = foldFDivConstantDivisor(I))
return R;
if (Instruction *R = foldFDivConstantDividend(I))
return R;
if (Instruction *R = foldFPSignBitOps(I))
return R;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
if (isa<Constant>(Op0))
if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
if (Instruction *R = FoldOpIntoSelect(I, SI))
return R;
if (isa<Constant>(Op1))
if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
if (Instruction *R = FoldOpIntoSelect(I, SI))
return R;
if (I.hasAllowReassoc() && I.hasAllowReciprocal()) {
Value *X, *Y;
if (match(Op0, m_OneUse(m_FDiv(m_Value(X), m_Value(Y)))) &&
(!isa<Constant>(Y) || !isa<Constant>(Op1))) {
// (X / Y) / Z => X / (Y * Z)
Value *YZ = Builder.CreateFMulFMF(Y, Op1, &I);
return BinaryOperator::CreateFDivFMF(X, YZ, &I);
}
if (match(Op1, m_OneUse(m_FDiv(m_Value(X), m_Value(Y)))) &&
(!isa<Constant>(Y) || !isa<Constant>(Op0))) {
// Z / (X / Y) => (Y * Z) / X
Value *YZ = Builder.CreateFMulFMF(Y, Op0, &I);
return BinaryOperator::CreateFDivFMF(YZ, X, &I);
}
// Z / (1.0 / Y) => (Y * Z)
//
// This is a special case of Z / (X / Y) => (Y * Z) / X, with X = 1.0. The
// m_OneUse check is avoided because even in the case of the multiple uses
// for 1.0/Y, the number of instructions remain the same and a division is
// replaced by a multiplication.
if (match(Op1, m_FDiv(m_SpecificFP(1.0), m_Value(Y))))
return BinaryOperator::CreateFMulFMF(Y, Op0, &I);
}
if (I.hasAllowReassoc() && Op0->hasOneUse() && Op1->hasOneUse()) {
// sin(X) / cos(X) -> tan(X)
// cos(X) / sin(X) -> 1/tan(X) (cotangent)
Value *X;
bool IsTan = match(Op0, m_Intrinsic<Intrinsic::sin>(m_Value(X))) &&
match(Op1, m_Intrinsic<Intrinsic::cos>(m_Specific(X)));
bool IsCot =
!IsTan && match(Op0, m_Intrinsic<Intrinsic::cos>(m_Value(X))) &&
match(Op1, m_Intrinsic<Intrinsic::sin>(m_Specific(X)));
if ((IsTan || IsCot) && hasFloatFn(M, &TLI, I.getType(), LibFunc_tan,
LibFunc_tanf, LibFunc_tanl)) {
IRBuilder<> B(&I);
IRBuilder<>::FastMathFlagGuard FMFGuard(B);
B.setFastMathFlags(I.getFastMathFlags());
AttributeList Attrs =
cast<CallBase>(Op0)->getCalledFunction()->getAttributes();
Value *Res = emitUnaryFloatFnCall(X, &TLI, LibFunc_tan, LibFunc_tanf,
LibFunc_tanl, B, Attrs);
if (IsCot)
Res = B.CreateFDiv(ConstantFP::get(I.getType(), 1.0), Res);
return replaceInstUsesWith(I, Res);
}
}
// X / (X * Y) --> 1.0 / Y
// Reassociate to (X / X -> 1.0) is legal when NaNs are not allowed.
// We can ignore the possibility that X is infinity because INF/INF is NaN.
Value *X, *Y;
if (I.hasNoNaNs() && I.hasAllowReassoc() &&
match(Op1, m_c_FMul(m_Specific(Op0), m_Value(Y)))) {
replaceOperand(I, 0, ConstantFP::get(I.getType(), 1.0));
replaceOperand(I, 1, Y);
return &I;
}
// X / fabs(X) -> copysign(1.0, X)
// fabs(X) / X -> copysign(1.0, X)
if (I.hasNoNaNs() && I.hasNoInfs() &&
(match(&I, m_FDiv(m_Value(X), m_FAbs(m_Deferred(X)))) ||
match(&I, m_FDiv(m_FAbs(m_Value(X)), m_Deferred(X))))) {
Value *V = Builder.CreateBinaryIntrinsic(
Intrinsic::copysign, ConstantFP::get(I.getType(), 1.0), X, &I);
return replaceInstUsesWith(I, V);
}
if (Instruction *Mul = foldFDivPowDivisor(I, Builder))
return Mul;
return nullptr;
}
/// This function implements the transforms common to both integer remainder
/// instructions (urem and srem). It is called by the visitors to those integer
/// remainder instructions.
/// Common integer remainder transforms
Instruction *InstCombinerImpl::commonIRemTransforms(BinaryOperator &I) {
if (Instruction *Phi = foldBinopWithPhiOperands(I))
return Phi;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// The RHS is known non-zero.
if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this, I))
return replaceOperand(I, 1, V);
// Handle cases involving: rem X, (select Cond, Y, Z)
if (simplifyDivRemOfSelectWithZeroOp(I))
return &I;
// If the divisor is a select-of-constants, try to constant fold all rem ops:
// C % (select Cond, TrueC, FalseC) --> select Cond, (C % TrueC), (C % FalseC)
// TODO: Adapt simplifyDivRemOfSelectWithZeroOp to allow this and other folds.
if (match(Op0, m_ImmConstant()) &&
match(Op1, m_Select(m_Value(), m_ImmConstant(), m_ImmConstant()))) {
if (Instruction *R = FoldOpIntoSelect(I, cast<SelectInst>(Op1),
/*FoldWithMultiUse*/ true))
return R;
}
if (isa<Constant>(Op1)) {
if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) {
if (SelectInst *SI = dyn_cast<SelectInst>(Op0I)) {
if (Instruction *R = FoldOpIntoSelect(I, SI))
return R;
} else if (auto *PN = dyn_cast<PHINode>(Op0I)) {
const APInt *Op1Int;
if (match(Op1, m_APInt(Op1Int)) && !Op1Int->isMinValue() &&
(I.getOpcode() == Instruction::URem ||
!Op1Int->isMinSignedValue())) {
// foldOpIntoPhi will speculate instructions to the end of the PHI's
// predecessor blocks, so do this only if we know the srem or urem
// will not fault.
if (Instruction *NV = foldOpIntoPhi(I, PN))
return NV;
}
}
// See if we can fold away this rem instruction.
if (SimplifyDemandedInstructionBits(I))
return &I;
}
}
return nullptr;
}
Instruction *InstCombinerImpl::visitURem(BinaryOperator &I) {
if (Value *V = simplifyURemInst(I.getOperand(0), I.getOperand(1),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (Instruction *X = foldVectorBinop(I))
return X;
if (Instruction *common = commonIRemTransforms(I))
return common;
if (Instruction *NarrowRem = narrowUDivURem(I, Builder))
return NarrowRem;
// X urem Y -> X and Y-1, where Y is a power of 2,
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
Type *Ty = I.getType();
if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/ true, 0, &I)) {
// This may increase instruction count, we don't enforce that Y is a
// constant.
Constant *N1 = Constant::getAllOnesValue(Ty);
Value *Add = Builder.CreateAdd(Op1, N1);
return BinaryOperator::CreateAnd(Op0, Add);
}
// 1 urem X -> zext(X != 1)
if (match(Op0, m_One())) {
Value *Cmp = Builder.CreateICmpNE(Op1, ConstantInt::get(Ty, 1));
return CastInst::CreateZExtOrBitCast(Cmp, Ty);
}
// Op0 urem C -> Op0 < C ? Op0 : Op0 - C, where C >= signbit.
// Op0 must be frozen because we are increasing its number of uses.
if (match(Op1, m_Negative())) {
Value *F0 = Builder.CreateFreeze(Op0, Op0->getName() + ".fr");
Value *Cmp = Builder.CreateICmpULT(F0, Op1);
Value *Sub = Builder.CreateSub(F0, Op1);
return SelectInst::Create(Cmp, F0, Sub);
}
// If the divisor is a sext of a boolean, then the divisor must be max
// unsigned value (-1). Therefore, the remainder is Op0 unless Op0 is also
// max unsigned value. In that case, the remainder is 0:
// urem Op0, (sext i1 X) --> (Op0 == -1) ? 0 : Op0
Value *X;
if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) {
Value *Cmp = Builder.CreateICmpEQ(Op0, ConstantInt::getAllOnesValue(Ty));
return SelectInst::Create(Cmp, ConstantInt::getNullValue(Ty), Op0);
}
return nullptr;
}
Instruction *InstCombinerImpl::visitSRem(BinaryOperator &I) {
if (Value *V = simplifySRemInst(I.getOperand(0), I.getOperand(1),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (Instruction *X = foldVectorBinop(I))
return X;
// Handle the integer rem common cases
if (Instruction *Common = commonIRemTransforms(I))
return Common;
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
{
const APInt *Y;
// X % -Y -> X % Y
if (match(Op1, m_Negative(Y)) && !Y->isMinSignedValue())
return replaceOperand(I, 1, ConstantInt::get(I.getType(), -*Y));
}
// -X srem Y --> -(X srem Y)
Value *X, *Y;
if (match(&I, m_SRem(m_OneUse(m_NSWSub(m_Zero(), m_Value(X))), m_Value(Y))))
return BinaryOperator::CreateNSWNeg(Builder.CreateSRem(X, Y));
// If the sign bits of both operands are zero (i.e. we can prove they are
// unsigned inputs), turn this into a urem.
APInt Mask(APInt::getSignMask(I.getType()->getScalarSizeInBits()));
if (MaskedValueIsZero(Op1, Mask, 0, &I) &&
MaskedValueIsZero(Op0, Mask, 0, &I)) {
// X srem Y -> X urem Y, iff X and Y don't have sign bit set
return BinaryOperator::CreateURem(Op0, Op1, I.getName());
}
// If it's a constant vector, flip any negative values positive.
if (isa<ConstantVector>(Op1) || isa<ConstantDataVector>(Op1)) {
Constant *C = cast<Constant>(Op1);
unsigned VWidth = cast<FixedVectorType>(C->getType())->getNumElements();
bool hasNegative = false;
bool hasMissing = false;
for (unsigned i = 0; i != VWidth; ++i) {
Constant *Elt = C->getAggregateElement(i);
if (!Elt) {
hasMissing = true;
break;
}
if (ConstantInt *RHS = dyn_cast<ConstantInt>(Elt))
if (RHS->isNegative())
hasNegative = true;
}
if (hasNegative && !hasMissing) {
SmallVector<Constant *, 16> Elts(VWidth);
for (unsigned i = 0; i != VWidth; ++i) {
Elts[i] = C->getAggregateElement(i); // Handle undef, etc.
if (ConstantInt *RHS = dyn_cast<ConstantInt>(Elts[i])) {
if (RHS->isNegative())
Elts[i] = cast<ConstantInt>(ConstantExpr::getNeg(RHS));
}
}
Constant *NewRHSV = ConstantVector::get(Elts);
if (NewRHSV != C) // Don't loop on -MININT
return replaceOperand(I, 1, NewRHSV);
}
}
return nullptr;
}
Instruction *InstCombinerImpl::visitFRem(BinaryOperator &I) {
if (Value *V = simplifyFRemInst(I.getOperand(0), I.getOperand(1),
I.getFastMathFlags(),
SQ.getWithInstruction(&I)))
return replaceInstUsesWith(I, V);
if (Instruction *X = foldVectorBinop(I))
return X;
if (Instruction *Phi = foldBinopWithPhiOperands(I))
return Phi;
return nullptr;
}
Reference in New Issue View Git Blame Copy Permalink