//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "instcombine"
#include "InstCombine.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/IR/IntrinsicInst.h"
using namespace llvm;
using namespace PatternMatch;
+#define DEBUG_TYPE "instcombine"
+
/// simplifyValueKnownNonZero - The specific integer value is used in a context
/// where it is known to be non-zero. If this allows us to simplify the
// 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 0;
+ 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 = 0, *B = 0, *PowerOf2 = 0;
+ Value *A = nullptr, *B = nullptr, *PowerOf2 = nullptr;
if (match(V, m_LShr(m_OneUse(m_Shl(m_Value(PowerOf2), m_Value(A))),
m_Value(B))) &&
// The "1" can be any value known to be a power of 2.
// 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 : 0;
+ return MadeChange ? V : nullptr;
}
return MulExt.slt(Min) || MulExt.sgt(Max);
}
+/// \brief True if C2 is a multiple of C1. Quotient contains C2/C1.
+static bool IsMultiple(const APInt &C1, const APInt &C2, APInt &Quotient,
+ bool IsSigned) {
+ assert(C1.getBitWidth() == C2.getBitWidth() &&
+ "Inconsistent width of constants!");
+
+ 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();
+}
+
/// \brief A helper routine of InstCombiner::visitMul().
///
/// If C is a vector of known powers of 2, then this function returns
for (unsigned I = 0, E = CV->getNumElements(); I != E; ++I) {
Constant *Elt = CV->getElementAsConstant(I);
if (!match(Elt, m_APInt(IVal)) || !IVal->isPowerOf2())
- return 0;
+ return nullptr;
Elts.push_back(ConstantInt::get(Elt->getType(), IVal->logBase2()));
}
bool Changed = SimplifyAssociativeOrCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (Value *V = SimplifyMulInst(Op0, Op1, DL))
return ReplaceInstUsesWith(I, V);
return BinaryOperator::CreateMul(NewOp, ConstantExpr::getShl(C1, C2));
if (match(&I, m_Mul(m_Value(NewOp), m_Constant(C1)))) {
- Constant *NewCst = 0;
+ Constant *NewCst = nullptr;
if (match(C1, m_APInt(IVal)) && IVal->isPowerOf2())
// Replace X*(2^C) with X << C, where C is either a scalar or a splat.
NewCst = ConstantInt::get(NewOp->getType(), IVal->logBase2());
const APInt & Val = CI->getValue();
const APInt &PosVal = Val.abs();
if (Val.isNegative() && PosVal.isPowerOf2()) {
- Value *X = 0, *Y = 0;
+ Value *X = nullptr, *Y = nullptr;
if (Op0->hasOneUse()) {
ConstantInt *C1;
- Value *Sub = 0;
+ Value *Sub = nullptr;
if (match(Op0, m_Sub(m_Value(Y), m_Value(X))))
Sub = Builder->CreateSub(X, Y, "suba");
else if (match(Op0, m_Add(m_Value(Y), m_ConstantInt(C1))))
Value *X;
Constant *C1;
if (match(Op0, m_OneUse(m_Add(m_Value(X), m_Constant(C1))))) {
- Value *Add = Builder->CreateMul(X, Op1);
- return BinaryOperator::CreateAdd(Add, Builder->CreateMul(C1, Op1));
+ 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);
}
}
}
// -2 is "-1 << 1" so it is all bits set except the low one.
APInt Negative2(I.getType()->getPrimitiveSizeInBits(), (uint64_t)-2, true);
- Value *BoolCast = 0, *OtherOp = 0;
+ Value *BoolCast = nullptr, *OtherOp = nullptr;
if (MaskedValueIsZero(Op0, Negative2))
BoolCast = Op0, OtherOp = Op1;
else if (MaskedValueIsZero(Op1, Negative2))
}
}
- return Changed ? &I : 0;
+ return Changed ? &I : nullptr;
}
//
Constant *C0 = dyn_cast<Constant>(Opnd0);
Constant *C1 = dyn_cast<Constant>(Opnd1);
- BinaryOperator *R = 0;
+ BinaryOperator *R = nullptr;
// (X * C0) * C => X * (C0*C)
if (FMulOrDiv->getOpcode() == Instruction::FMul) {
bool Changed = SimplifyAssociativeOrCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (isa<Constant>(Op0))
std::swap(Op0, Op1);
Value *M1 = ConstantExpr::getFMul(C1, C);
Value *M0 = isNormalFp(cast<Constant>(M1)) ?
foldFMulConst(cast<Instruction>(Opnd0), C, &I) :
- 0;
+ nullptr;
if (M0 && M1) {
if (Swap && FAddSub->getOpcode() == Instruction::FSub)
std::swap(M0, M1);
// Under unsafe algebra do:
// X * log2(0.5*Y) = X*log2(Y) - X
if (I.hasUnsafeAlgebra()) {
- Value *OpX = NULL;
- Value *OpY = NULL;
+ Value *OpX = nullptr;
+ Value *OpY = nullptr;
IntrinsicInst *Log2;
detectLog2OfHalf(Op0, OpY, Log2);
if (OpY) {
Value *Opnd0_0, *Opnd0_1;
if (Opnd0->hasOneUse() &&
match(Opnd0, m_FMul(m_Value(Opnd0_0), m_Value(Opnd0_1)))) {
- Value *Y = 0;
+ Value *Y = nullptr;
if (Opnd0_0 == Opnd1 && Opnd0_1 != Opnd1)
Y = Opnd0_1;
else if (Opnd0_1 == Opnd1 && Opnd0_0 != Opnd1)
}
}
- // B * (uitofp i1 C) -> select C, B, 0
- if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
- Value *LHS = Op0, *RHS = Op1;
- Value *B, *C;
- if (!match(RHS, m_UIToFP(m_Value(C))))
- std::swap(LHS, RHS);
-
- if (match(RHS, m_UIToFP(m_Value(C))) &&
- C->getType()->getScalarType()->isIntegerTy(1)) {
- B = LHS;
- Value *Zero = ConstantFP::getNegativeZero(B->getType());
- return SelectInst::Create(C, B, Zero);
- }
- }
-
- // A * (1 - uitofp i1 C) -> select C, 0, A
- if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
- Value *LHS = Op0, *RHS = Op1;
- Value *A, *C;
- if (!match(RHS, m_FSub(m_FPOne(), m_UIToFP(m_Value(C)))))
- std::swap(LHS, RHS);
-
- if (match(RHS, m_FSub(m_FPOne(), m_UIToFP(m_Value(C)))) &&
- C->getType()->getScalarType()->isIntegerTy(1)) {
- A = LHS;
- Value *Zero = ConstantFP::getNegativeZero(A->getType());
- return SelectInst::Create(C, Zero, A);
- }
- }
-
if (!isa<Constant>(Op1))
std::swap(Opnd0, Opnd1);
else
break;
}
- return Changed ? &I : 0;
+ return Changed ? &I : nullptr;
}
/// SimplifyDivRemOfSelect - Try to fold a divide or remainder of a select
// If we past the instruction, quit looking for it.
if (&*BBI == SI)
- SI = 0;
+ SI = nullptr;
if (&*BBI == SelectCond)
- SelectCond = 0;
+ SelectCond = nullptr;
// If we ran out of things to eliminate, break out of the loop.
- if (SelectCond == 0 && SI == 0)
+ if (!SelectCond && !SI)
break;
}
return &I;
if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- // (X / C1) / C2 -> X / (C1*C2)
- if (Instruction *LHS = dyn_cast<Instruction>(Op0))
+ if (Instruction *LHS = dyn_cast<Instruction>(Op0)) {
+ // (X / C1) / C2 -> X / (C1*C2)
if (Instruction::BinaryOps(LHS->getOpcode()) == I.getOpcode())
if (ConstantInt *LHSRHS = dyn_cast<ConstantInt>(LHS->getOperand(1))) {
if (MultiplyOverflows(RHS, LHSRHS,
- I.getOpcode()==Instruction::SDiv))
+ I.getOpcode() == Instruction::SDiv))
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
return BinaryOperator::Create(I.getOpcode(), LHS->getOperand(0),
ConstantExpr::getMul(RHS, LHSRHS));
}
+ Value *X;
+ const APInt *C1, *C2;
+ if (match(RHS, m_APInt(C2))) {
+ bool IsSigned = I.getOpcode() == Instruction::SDiv;
+ if ((IsSigned && match(LHS, m_NSWMul(m_Value(X), m_APInt(C1)))) ||
+ (!IsSigned && match(LHS, 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)) {
+ BinaryOperator *BO = BinaryOperator::Create(
+ I.getOpcode(), X, ConstantInt::get(X->getType(), Quotient));
+ BO->setIsExact(I.isExact());
+ return BO;
+ }
+
+ // (X * C1) / C2 -> X * (C1 / C2) if C1 is a multiple of C2.
+ if (IsMultiple(*C1, *C2, Quotient, IsSigned)) {
+ BinaryOperator *BO = BinaryOperator::Create(
+ Instruction::Mul, X, ConstantInt::get(X->getType(), Quotient));
+ BO->setHasNoUnsignedWrap(
+ !IsSigned &&
+ cast<OverflowingBinaryOperator>(LHS)->hasNoUnsignedWrap());
+ BO->setHasNoSignedWrap(
+ cast<OverflowingBinaryOperator>(LHS)->hasNoSignedWrap());
+ return BO;
+ }
+ }
+
+ if ((IsSigned && match(LHS, m_NSWShl(m_Value(X), m_APInt(C1)))) ||
+ (!IsSigned && match(LHS, m_NUWShl(m_Value(X), m_APInt(C1))))) {
+ APInt Quotient(C1->getBitWidth(), /*Val=*/0ULL, IsSigned);
+ APInt C1Shifted = APInt::getOneBitSet(
+ C1->getBitWidth(), static_cast<unsigned>(C1->getLimitedValue()));
+
+ // (X << C1) / C2 -> X / (C2 >> C1) if C2 is a multiple of C1.
+ if (IsMultiple(*C2, C1Shifted, Quotient, IsSigned)) {
+ BinaryOperator *BO = BinaryOperator::Create(
+ I.getOpcode(), X, ConstantInt::get(X->getType(), Quotient));
+ BO->setIsExact(I.isExact());
+ return BO;
+ }
+
+ // (X << C1) / C2 -> X * (C2 >> C1) if C1 is a multiple of C2.
+ if (IsMultiple(C1Shifted, *C2, Quotient, IsSigned)) {
+ BinaryOperator *BO = BinaryOperator::Create(
+ Instruction::Mul, X, ConstantInt::get(X->getType(), Quotient));
+ BO->setHasNoUnsignedWrap(
+ !IsSigned &&
+ cast<OverflowingBinaryOperator>(LHS)->hasNoUnsignedWrap());
+ BO->setHasNoSignedWrap(
+ cast<OverflowingBinaryOperator>(LHS)->hasNoSignedWrap());
+ return BO;
+ }
+ }
+ }
+ }
+
if (!RHS->isZero()) { // avoid X udiv 0
if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
if (Instruction *R = FoldOpIntoSelect(I, SI))
}
}
+ if (ConstantInt *One = dyn_cast<ConstantInt>(Op0)) {
+ if (One->isOne() && !I.getType()->isIntegerTy(1)) {
+ bool isSigned = I.getOpcode() == Instruction::SDiv;
+ if (isSigned) {
+ // If Op1 is 0 then it's undefined behaviour, if Op1 is 1 then the
+ // result is one, if Op1 is -1 then the result is minus one, otherwise
+ // it's zero.
+ Value *Inc = Builder->CreateAdd(Op1, One);
+ Value *Cmp = Builder->CreateICmpULT(
+ Inc, ConstantInt::get(I.getType(), 3));
+ return SelectInst::Create(Cmp, Op1, ConstantInt::get(I.getType(), 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, One), I.getType());
+ }
+ }
+ }
+
// 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 = 0, *Z = 0;
+ Value *X = nullptr, *Z = nullptr;
if (match(Op0, m_Sub(m_Value(X), m_Value(Z)))) { // (X - Z) / Y; Y = Op1
bool isSigned = I.getOpcode() == Instruction::SDiv;
if ((isSigned && match(Z, m_SRem(m_Specific(X), m_Specific(Op1)))) ||
return BinaryOperator::Create(I.getOpcode(), X, Op1);
}
- return 0;
+ return nullptr;
}
/// dyn_castZExtVal - Checks if V is a zext or constant that can
if (C->getValue().getActiveBits() <= cast<IntegerType>(Ty)->getBitWidth())
return ConstantExpr::getTrunc(C, Ty);
}
- return 0;
+ return nullptr;
}
namespace {
};
UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand)
- : FoldAction(FA), OperandToFold(InputOperand), FoldResult(0) {}
+ : FoldAction(FA), OperandToFold(InputOperand), FoldResult(nullptr) {}
UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand, size_t SLHS)
: FoldAction(FA), OperandToFold(InputOperand), SelectLHSIdx(SLHS) {}
};
return 0;
if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
- if (size_t LHSIdx = visitUDivOperand(Op0, SI->getOperand(1), I, Actions))
- if (visitUDivOperand(Op0, SI->getOperand(2), I, Actions)) {
- Actions.push_back(UDivFoldAction((FoldUDivOperandCb)0, Op1, LHSIdx-1));
+ if (size_t LHSIdx =
+ visitUDivOperand(Op0, SI->getOperand(1), I, Actions, Depth))
+ if (visitUDivOperand(Op0, SI->getOperand(2), I, Actions, Depth)) {
+ Actions.push_back(UDivFoldAction(nullptr, Op1, LHSIdx - 1));
return Actions.size();
}
Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (Value *V = SimplifyUDivInst(Op0, Op1, DL))
return ReplaceInstUsesWith(I, V);
return Inst;
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (Value *V = SimplifySDivInst(Op0, Op1, DL))
return ReplaceInstUsesWith(I, V);
}
if (Constant *RHS = dyn_cast<Constant>(Op1)) {
+ // X/INT_MIN -> X == INT_MIN
+ if (RHS->isMinSignedValue())
+ return new ZExtInst(Builder->CreateICmpEQ(Op0, Op1), I.getType());
+
// -X/C --> X/-C provided the negation doesn't overflow.
if (SubOperator *Sub = dyn_cast<SubOperator>(Op0))
if (match(Sub->getOperand(0), m_Zero()) && Sub->hasNoSignedWrap())
}
}
- return 0;
+ return nullptr;
}
/// CvtFDivConstToReciprocal tries to convert X/C into X*1/C if C not a special
Constant *Divisor,
bool AllowReciprocal) {
if (!isa<ConstantFP>(Divisor)) // TODO: handle vectors.
- return 0;
+ return nullptr;
const APFloat &FpVal = cast<ConstantFP>(Divisor)->getValueAPF();
APFloat Reciprocal(FpVal.getSemantics());
}
if (!Cvt)
- return 0;
+ return nullptr;
ConstantFP *R;
R = ConstantFP::get(Dividend->getType()->getContext(), Reciprocal);
Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (Value *V = SimplifyFDivInst(Op0, Op1, DL))
return ReplaceInstUsesWith(I, V);
return R;
if (AllowReassociate) {
- Constant *C1 = 0;
+ Constant *C1 = nullptr;
Constant *C2 = Op1C;
Value *X;
- Instruction *Res = 0;
+ Instruction *Res = nullptr;
if (match(Op0, m_FMul(m_Value(X), m_Constant(C1)))) {
// (X*C1)/C2 => X * (C1/C2)
return T;
}
- return 0;
+ return nullptr;
}
if (AllowReassociate && isa<Constant>(Op0)) {
Constant *C1 = cast<Constant>(Op0), *C2;
- Constant *Fold = 0;
+ Constant *Fold = nullptr;
Value *X;
bool CreateDiv = true;
R->setFastMathFlags(I.getFastMathFlags());
return R;
}
- return 0;
+ return nullptr;
}
if (AllowReassociate) {
Value *X, *Y;
- Value *NewInst = 0;
- Instruction *SimpR = 0;
+ Value *NewInst = nullptr;
+ Instruction *SimpR = nullptr;
if (Op0->hasOneUse() && match(Op0, m_FDiv(m_Value(X), m_Value(Y)))) {
// (X/Y) / Z => X / (Y*Z)
}
}
- return 0;
+ return nullptr;
}
/// This function implements the transforms common to both integer remainder
}
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitURem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (Value *V = SimplifyURemInst(Op0, Op1, DL))
return ReplaceInstUsesWith(I, V);
return ReplaceInstUsesWith(I, Ext);
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitSRem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (Value *V = SimplifySRemInst(Op0, Op1, DL))
return ReplaceInstUsesWith(I, V);
bool hasMissing = false;
for (unsigned i = 0; i != VWidth; ++i) {
Constant *Elt = C->getAggregateElement(i);
- if (Elt == 0) {
+ if (!Elt) {
hasMissing = true;
break;
}
}
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitFRem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (Value *V = SimplifyFRemInst(Op0, Op1, DL))
return ReplaceInstUsesWith(I, V);
if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
return &I;
- return 0;
+ return nullptr;
}
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