//
//===----------------------------------------------------------------------===//
-#include "InstCombine.h"
+#include "InstCombineInternal.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/Support/PatternMatch.h"
+#include "llvm/IR/PatternMatch.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
-/// computation, do so and return the new operand, otherwise return null.
-static Value *simplifyValueKnownNonZero(Value *V, InstCombiner &IC) {
+
+/// 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, InstCombiner &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 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;
- 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.
- isKnownToBeAPowerOfTwo(PowerOf2)) {
+ 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(PowerOf2, A);
+ return IC.Builder->CreateShl(One, A);
}
// (PowerOfTwo >>u B) --> isExact since shifting out the result would make it
// inexact. Similarly for <<.
if (BinaryOperator *I = dyn_cast<BinaryOperator>(V))
- if (I->isLogicalShift() && isKnownToBeAPowerOfTwo(I->getOperand(0))) {
+ if (I->isLogicalShift() &&
+ isKnownToBeAPowerOfTwo(I->getOperand(0), IC.getDataLayout(), false, 0,
+ IC.getAssumptionCache(), &CxtI,
+ IC.getDominatorTree())) {
// 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)) {
+ if (Value *V2 = simplifyValueKnownNonZero(I->getOperand(0), IC, CxtI)) {
I->setOperand(0, V2);
MadeChange = true;
}
// 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;
}
-/// MultiplyOverflows - True if the multiply can not be expressed in an int
-/// this size.
-static bool MultiplyOverflows(ConstantInt *C1, ConstantInt *C2, bool sign) {
- uint32_t W = C1->getBitWidth();
- APInt LHSExt = C1->getValue(), RHSExt = C2->getValue();
- if (sign) {
- LHSExt = LHSExt.sext(W * 2);
- RHSExt = RHSExt.sext(W * 2);
- } else {
- LHSExt = LHSExt.zext(W * 2);
- RHSExt = RHSExt.zext(W * 2);
- }
+/// 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;
+ if (IsSigned)
+ Product = C1.smul_ov(C2, Overflow);
+ else
+ Product = C1.umul_ov(C2, Overflow);
- APInt MulExt = LHSExt * RHSExt;
+ return Overflow;
+}
- if (!sign)
- return MulExt.ugt(APInt::getLowBitsSet(W * 2, W));
+/// \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 Min = APInt::getSignedMinValue(W).sext(W * 2);
- APInt Max = APInt::getSignedMaxValue(W).sext(W * 2);
- return MulExt.slt(Min) || MulExt.sgt(Max);
+ // Bail if we will divide by zero.
+ if (C2.isMinValue())
+ return false;
+
+ // Bail if we would divide INT_MIN by -1.
+ if (IsSigned && C1.isMinSignedValue() && C2.isAllOnesValue())
+ 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();
}
/// \brief A helper routine of InstCombiner::visitMul().
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()));
}
return ConstantVector::get(Elts);
}
+/// \brief Return true if we can prove that:
+/// (mul LHS, RHS) === (mul nsw LHS, RHS)
+bool InstCombiner::WillNotOverflowSignedMul(Value *LHS, Value *RHS,
+ Instruction &CxtI) {
+ // Multiplying n * m significant bits yields a result of n + m significant
+ // bits. If the total number of significant bits does not exceed the
+ // result bit width (minus 1), there is no overflow.
+ // This means if we have enough leading sign bits in the operands
+ // we can guarantee that the result does not overflow.
+ // Ref: "Hacker's Delight" by Henry Warren
+ unsigned BitWidth = LHS->getType()->getScalarSizeInBits();
+
+ // Note that underestimating the number of sign bits gives a more
+ // conservative answer.
+ unsigned SignBits =
+ ComputeNumSignBits(LHS, 0, &CxtI) + ComputeNumSignBits(RHS, 0, &CxtI);
+
+ // First handle the easy case: if we have enough sign bits there's
+ // definitely no overflow.
+ if (SignBits > BitWidth + 1)
+ return true;
+
+ // There are two ambiguous cases where there can be no overflow:
+ // SignBits == BitWidth + 1 and
+ // SignBits == BitWidth
+ // The second case is difficult to check, therefore we only handle the
+ // first case.
+ if (SignBits == BitWidth + 1) {
+ // It overflows only when both arguments are negative and the true
+ // product is exactly the minimum negative number.
+ // E.g. mul i16 with 17 sign bits: 0xff00 * 0xff80 = 0x8000
+ // For simplicity we just check if at least one side is not negative.
+ bool LHSNonNegative, LHSNegative;
+ bool RHSNonNegative, RHSNegative;
+ ComputeSignBit(LHS, LHSNonNegative, LHSNegative, /*Depth=*/0, &CxtI);
+ ComputeSignBit(RHS, RHSNonNegative, RHSNegative, /*Depth=*/0, &CxtI);
+ if (LHSNonNegative || RHSNonNegative)
+ return true;
+ }
+ return false;
+}
+
Instruction *InstCombiner::visitMul(BinaryOperator &I) {
bool Changed = SimplifyAssociativeOrCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifyMulInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifyMulInst(Op0, Op1, DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
if (Value *V = SimplifyUsingDistributiveLaws(I))
return ReplaceInstUsesWith(I, V);
- if (match(Op1, m_AllOnes())) // X * -1 == 0 - X
- return BinaryOperator::CreateNeg(Op0, I.getName());
+ // 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.
{
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 << C1)*C2) == (X * (C2 << C1))
- return BinaryOperator::CreateMul(NewOp, ConstantExpr::getShl(C1, C2));
+ 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)))) {
- 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());
NewCst = getLogBase2Vector(CV);
if (NewCst) {
+ unsigned Width = NewCst->getType()->getPrimitiveSizeInBits();
BinaryOperator *Shl = BinaryOperator::CreateShl(NewOp, NewCst);
- if (I.hasNoSignedWrap()) Shl->setHasNoSignedWrap();
- if (I.hasNoUnsignedWrap()) Shl->setHasNoUnsignedWrap();
+
+ if (I.hasNoUnsignedWrap())
+ Shl->setHasNoUnsignedWrap();
+ if (I.hasNoSignedWrap()) {
+ uint64_t V;
+ if (match(NewCst, m_ConstantInt(V)) && V != Width - 1)
+ Shl->setHasNoSignedWrap();
+ }
+
return Shl;
}
}
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);
}
}
}
- if (Value *Op0v = dyn_castNegVal(Op0)) // -X * -Y = X*Y
- if (Value *Op1v = dyn_castNegVal(Op1))
- return BinaryOperator::CreateMul(Op0v, Op1v);
+ if (Value *Op0v = dyn_castNegVal(Op0)) { // -X * -Y = X*Y
+ if (Value *Op1v = dyn_castNegVal(Op1)) {
+ BinaryOperator *BO = BinaryOperator::CreateMul(Op0v, Op1v);
+ if (I.hasNoSignedWrap() &&
+ match(Op0, m_NSWSub(m_Value(), m_Value())) &&
+ match(Op1, m_NSWSub(m_Value(), m_Value())))
+ BO->setHasNoSignedWrap();
+ return BO;
+ }
+ }
// (X / Y) * Y = X - (X % Y)
// (X / Y) * -Y = (X % Y) - X
// (1 << Y)*X --> X << Y
{
Value *Y;
- if (match(Op0, m_Shl(m_One(), m_Value(Y))))
- return BinaryOperator::CreateShl(Op1, Y);
- if (match(Op1, m_Shl(m_One(), m_Value(Y))))
- return BinaryOperator::CreateShl(Op0, 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;
+ }
}
// If one of the operands of the multiply is a cast from a boolean value, then
// -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;
- if (MaskedValueIsZero(Op0, Negative2))
+ Value *BoolCast = nullptr, *OtherOp = nullptr;
+ if (MaskedValueIsZero(Op0, Negative2, 0, &I))
BoolCast = Op0, OtherOp = Op1;
- else if (MaskedValueIsZero(Op1, Negative2))
+ else if (MaskedValueIsZero(Op1, Negative2, 0, &I))
BoolCast = Op1, OtherOp = Op0;
if (BoolCast) {
}
}
- return Changed ? &I : 0;
-}
+ if (!I.hasNoSignedWrap() && WillNotOverflowSignedMul(Op0, Op1, I)) {
+ Changed = true;
+ I.setHasNoSignedWrap(true);
+ }
-//
-// Detect pattern:
-//
-// log2(Y*0.5)
-//
-// And check for corresponding fast math flags
-//
+ if (!I.hasNoUnsignedWrap() &&
+ computeOverflowForUnsignedMul(Op0, Op1, &I) ==
+ OverflowResult::NeverOverflows) {
+ Changed = true;
+ I.setHasNoUnsignedWrap(true);
+ }
-static void detectLog2OfHalf(Value *&Op, Value *&Y, IntrinsicInst *&Log2) {
+ return Changed ? &I : nullptr;
+}
- if (!Op->hasOneUse())
- return;
-
- IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op);
- if (!II)
- return;
- if (II->getIntrinsicID() != Intrinsic::log2 || !II->hasUnsafeAlgebra())
- return;
- Log2 = II;
-
- Value *OpLog2Of = II->getArgOperand(0);
- if (!OpLog2Of->hasOneUse())
- return;
-
- Instruction *I = dyn_cast<Instruction>(OpLog2Of);
- if (!I)
- return;
- if (I->getOpcode() != Instruction::FMul || !I->hasUnsafeAlgebra())
- return;
-
- if (match(I->getOperand(0), m_SpecificFP(0.5)))
- Y = I->getOperand(1);
- else if (match(I->getOperand(1), m_SpecificFP(0.5)))
- Y = I->getOperand(0);
+/// Detect pattern log2(Y * 0.5) with corresponding fast math flags.
+static void detectLog2OfHalf(Value *&Op, Value *&Y, IntrinsicInst *&Log2) {
+ if (!Op->hasOneUse())
+ return;
+
+ IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op);
+ if (!II)
+ return;
+ if (II->getIntrinsicID() != Intrinsic::log2 || !II->hasUnsafeAlgebra())
+ return;
+ Log2 = II;
+
+ Value *OpLog2Of = II->getArgOperand(0);
+ if (!OpLog2Of->hasOneUse())
+ return;
+
+ Instruction *I = dyn_cast<Instruction>(OpLog2Of);
+ if (!I)
+ return;
+ if (I->getOpcode() != Instruction::FMul || !I->hasUnsafeAlgebra())
+ return;
+
+ if (match(I->getOperand(0), m_SpecificFP(0.5)))
+ Y = I->getOperand(1);
+ else if (match(I->getOperand(1), m_SpecificFP(0.5)))
+ Y = I->getOperand(0);
}
static bool isFiniteNonZeroFp(Constant *C) {
if (C->getType()->isVectorTy()) {
for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E;
++I) {
- ConstantFP *CFP = dyn_cast<ConstantFP>(C->getAggregateElement(I));
+ ConstantFP *CFP = dyn_cast_or_null<ConstantFP>(C->getAggregateElement(I));
if (!CFP || !CFP->getValueAPF().isFiniteNonZero())
return false;
}
if (C->getType()->isVectorTy()) {
for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E;
++I) {
- ConstantFP *CFP = dyn_cast<ConstantFP>(C->getAggregateElement(I));
+ ConstantFP *CFP = dyn_cast_or_null<ConstantFP>(C->getAggregateElement(I));
if (!CFP || !CFP->getValueAPF().isNormal())
return false;
}
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);
- if (Value *V = SimplifyFMulInst(Op0, Op1, I.getFastMathFlags(), TD))
+ if (Value *V =
+ SimplifyFMulInst(Op0, Op1, I.getFastMathFlags(), DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
bool AllowReassociate = I.hasUnsafeAlgebra();
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);
}
}
+ // sqrt(X) * sqrt(X) -> X
+ if (AllowReassociate && (Op0 == Op1))
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op0))
+ if (II->getIntrinsicID() == Intrinsic::sqrt)
+ return ReplaceInstUsesWith(I, II->getOperand(0));
// Under unsafe algebra do:
// X * log2(0.5*Y) = X*log2(Y) - X
- if (I.hasUnsafeAlgebra()) {
- Value *OpX = NULL;
- Value *OpY = NULL;
+ if (AllowReassociate) {
+ 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
-/// instruction.
+/// Try to fold a divide or remainder of a select instruction.
bool InstCombiner::SimplifyDivRemOfSelect(BinaryOperator &I) {
SelectInst *SI = cast<SelectInst>(I.getOperand(1));
return true;
// Scan the current block backward, looking for other uses of SI.
- BasicBlock::iterator BBI = &I, BBFront = I.getParent()->begin();
+ BasicBlock::iterator BBI = I.getIterator(), BBFront = I.getParent()->begin();
while (BBI != BBFront) {
--BBI;
I != E; ++I) {
if (*I == SI) {
*I = SI->getOperand(NonNullOperand);
- Worklist.Add(BBI);
+ Worklist.Add(&*BBI);
} else if (*I == SelectCond) {
*I = Builder->getInt1(NonNullOperand == 1);
- Worklist.Add(BBI);
+ Worklist.Add(&*BBI);
}
}
// 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;
}
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// The RHS is known non-zero.
- if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this)) {
+ if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this, I)) {
I.setOperand(1, V);
return &I;
}
if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
return &I;
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
- // (X / C1) / C2 -> X / (C1*C2)
- if (Instruction *LHS = dyn_cast<Instruction>(Op0))
- if (Instruction::BinaryOps(LHS->getOpcode()) == I.getOpcode())
- if (ConstantInt *LHSRHS = dyn_cast<ConstantInt>(LHS->getOperand(1))) {
- if (MultiplyOverflows(RHS, LHSRHS,
- I.getOpcode()==Instruction::SDiv))
- return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- return BinaryOperator::Create(I.getOpcode(), LHS->getOperand(0),
- ConstantExpr::getMul(RHS, LHSRHS));
+ if (Instruction *LHS = dyn_cast<Instruction>(Op0)) {
+ const APInt *C2;
+ if (match(Op1, m_APInt(C2))) {
+ Value *X;
+ const APInt *C1;
+ bool IsSigned = I.getOpcode() == Instruction::SDiv;
+
+ // (X / C1) / C2 -> X / (C1*C2)
+ if ((IsSigned && match(LHS, m_SDiv(m_Value(X), m_APInt(C1)))) ||
+ (!IsSigned && match(LHS, 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(I.getType(), Product));
+ }
+
+ 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;
}
- if (!RHS->isZero()) { // avoid X udiv 0
- if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
- if (Instruction *R = FoldOpIntoSelect(I, SI))
- return R;
- if (isa<PHINode>(Op0))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
+ // (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))) &&
+ *C1 != C1->getBitWidth() - 1) ||
+ (!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 (*C2 != 0) { // avoid X udiv 0
+ if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+ if (Instruction *R = FoldOpIntoSelect(I, SI))
+ return R;
+ if (isa<PHINode>(Op0))
+ if (Instruction *NV = FoldOpIntoPhi(I))
+ return NV;
+ }
+ }
+ }
+
+ 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());
+ }
}
}
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) {}
};
const APInt &C = cast<Constant>(Op1)->getUniqueInteger();
BinaryOperator *LShr = BinaryOperator::CreateLShr(
Op0, ConstantInt::get(Op0->getType(), C.logBase2()));
- if (I.isExact()) LShr->setIsExact();
+ if (I.isExact())
+ LShr->setIsExact();
return LShr;
}
if (ZExtInst *Z = dyn_cast<ZExtInst>(Op1))
N = IC.Builder->CreateZExt(N, Z->getDestTy());
BinaryOperator *LShr = BinaryOperator::CreateLShr(Op0, N);
- if (I.isExact()) LShr->setIsExact();
+ if (I.isExact())
+ LShr->setIsExact();
return LShr;
}
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 = SimplifyUDivInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifyUDivInst(Op0, Op1, DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
// Handle the integer div common cases
return Common;
// (x lshr C1) udiv C2 --> x udiv (C2 << C1)
- if (Constant *C2 = dyn_cast<Constant>(Op1)) {
+ {
Value *X;
- Constant *C1;
- if (match(Op0, m_LShr(m_Value(X), m_Constant(C1))))
- return BinaryOperator::CreateUDiv(X, ConstantExpr::getShl(C2, C1));
+ const APInt *C1, *C2;
+ if (match(Op0, m_LShr(m_Value(X), m_APInt(C1))) &&
+ match(Op1, m_APInt(C2))) {
+ 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;
+ }
+ }
}
// (zext A) udiv (zext B) --> zext (A udiv B)
if (ZExtInst *ZOp0 = dyn_cast<ZExtInst>(Op0))
if (Value *ZOp1 = dyn_castZExtVal(Op1, ZOp0->getSrcTy()))
- return new ZExtInst(Builder->CreateUDiv(ZOp0->getOperand(0), ZOp1, "div",
- I.isExact()),
- I.getType());
+ return new ZExtInst(
+ Builder->CreateUDiv(ZOp0->getOperand(0), ZOp1, "div", I.isExact()),
+ I.getType());
// (LHS udiv (select (select (...)))) -> (LHS >> (select (select (...))))
SmallVector<UDivFoldAction, 6> UDivActions;
return Inst;
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifySDivInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifySDivInst(Op0, Op1, DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
// Handle the integer div common cases
}
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 BinaryOperator::CreateSDiv(Sub->getOperand(1),
- ConstantExpr::getNeg(RHS));
+ Value *X;
+ if (match(Op0, m_NSWSub(m_Zero(), m_Value(X)))) {
+ auto *BO = BinaryOperator::CreateSDiv(X, ConstantExpr::getNeg(RHS));
+ BO->setIsExact(I.isExact());
+ return BO;
+ }
}
// If the sign bits of both operands are zero (i.e. we can prove they are
// unsigned inputs), turn this into a udiv.
if (I.getType()->isIntegerTy()) {
APInt Mask(APInt::getSignBit(I.getType()->getPrimitiveSizeInBits()));
- if (MaskedValueIsZero(Op0, Mask)) {
- if (MaskedValueIsZero(Op1, Mask)) {
+ 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
- return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
+ auto *BO = BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
+ BO->setIsExact(I.isExact());
+ return BO;
}
- if (match(Op1, m_Shl(m_Power2(), m_Value()))) {
+ if (isKnownToBeAPowerOfTwo(Op1, DL, /*OrZero*/ true, 0, AC, &I, DT)) {
// 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.
- return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
+ auto *BO = BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
+ BO->setIsExact(I.isExact());
+ return BO;
}
}
}
- return 0;
+ return nullptr;
}
/// CvtFDivConstToReciprocal tries to convert X/C into X*1/C if C not a special
/// If the conversion was successful, the simplified expression "X * 1/C" is
/// returned; otherwise, NULL is returned.
///
-static Instruction *CvtFDivConstToReciprocal(Value *Dividend,
- Constant *Divisor,
+static Instruction *CvtFDivConstToReciprocal(Value *Dividend, 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 = SimplifyFDivInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifyFDivInst(Op0, Op1, I.getFastMathFlags(),
+ DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
if (isa<Constant>(Op0))
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
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// The RHS is known non-zero.
- if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this)) {
+ if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this, I)) {
I.setOperand(1, V);
return &I;
}
}
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitURem(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Value *V = SimplifyURemInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifyURemInst(Op0, Op1, DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
if (Instruction *common = commonIRemTransforms(I))
I.getType());
// X urem Y -> X and Y-1, where Y is a power of 2,
- if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true)) {
+ if (isKnownToBeAPowerOfTwo(Op1, DL, /*OrZero*/ true, 0, AC, &I, DT)) {
Constant *N1 = Constant::getAllOnesValue(I.getType());
Value *Add = Builder->CreateAdd(Op1, N1);
return BinaryOperator::CreateAnd(Op0, Add);
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 = SimplifySRemInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifySRemInst(Op0, Op1, DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
// Handle the integer rem common cases
if (Instruction *Common = commonIRemTransforms(I))
return Common;
- if (Value *RHSNeg = dyn_castNegVal(Op1))
- if (!isa<Constant>(RHSNeg) ||
- (isa<ConstantInt>(RHSNeg) &&
- cast<ConstantInt>(RHSNeg)->getValue().isStrictlyPositive())) {
- // X % -Y -> X % Y
+ {
+ const APInt *Y;
+ // X % -Y -> X % Y
+ if (match(Op1, m_APInt(Y)) && Y->isNegative() && !Y->isMinSignedValue()) {
Worklist.AddValue(I.getOperand(1));
- I.setOperand(1, RHSNeg);
+ I.setOperand(1, ConstantInt::get(I.getType(), -*Y));
return &I;
}
+ }
// If the sign bits of both operands are zero (i.e. we can prove they are
// unsigned inputs), turn this into a urem.
if (I.getType()->isIntegerTy()) {
APInt Mask(APInt::getSignBit(I.getType()->getPrimitiveSizeInBits()));
- if (MaskedValueIsZero(Op1, Mask) && MaskedValueIsZero(Op0, Mask)) {
+ 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());
}
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 = SimplifyFRemInst(Op0, Op1, TD))
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
+ if (Value *V = SimplifyFRemInst(Op0, Op1, I.getFastMathFlags(),
+ DL, TLI, DT, AC))
return ReplaceInstUsesWith(I, V);
// Handle cases involving: rem X, (select Cond, Y, Z)
if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
return &I;
- return 0;
+ return nullptr;
}
projects / oota-llvm.git / blobdiff