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path: root/lib/Transforms/InstCombine/InstCombineShifts.cpp
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Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineShifts.cpp')
-rw-r--r--lib/Transforms/InstCombine/InstCombineShifts.cpp53
1 files changed, 28 insertions, 25 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineShifts.cpp b/lib/Transforms/InstCombine/InstCombineShifts.cpp
index 2495747..afa907a 100644
--- a/lib/Transforms/InstCombine/InstCombineShifts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineShifts.cpp
@@ -68,7 +68,7 @@ Instruction *InstCombiner::commonShiftTransforms(BinaryOperator &I) {
/// this succeeds, the GetShiftedValue function will be called to produce the
/// value.
static bool CanEvaluateShifted(Value *V, unsigned NumBits, bool isLeftShift,
- InstCombiner &IC) {
+ InstCombiner &IC, Instruction *CxtI) {
// We can always evaluate constants shifted.
if (isa<Constant>(V))
return true;
@@ -111,8 +111,8 @@ static bool CanEvaluateShifted(Value *V, unsigned NumBits, bool isLeftShift,
case Instruction::Or:
case Instruction::Xor:
// Bitwise operators can all arbitrarily be arbitrarily evaluated shifted.
- return CanEvaluateShifted(I->getOperand(0), NumBits, isLeftShift, IC) &&
- CanEvaluateShifted(I->getOperand(1), NumBits, isLeftShift, IC);
+ return CanEvaluateShifted(I->getOperand(0), NumBits, isLeftShift, IC, I) &&
+ CanEvaluateShifted(I->getOperand(1), NumBits, isLeftShift, IC, I);
case Instruction::Shl: {
// We can often fold the shift into shifts-by-a-constant.
@@ -131,8 +131,9 @@ static bool CanEvaluateShifted(Value *V, unsigned NumBits, bool isLeftShift,
// profitable unless we know the and'd out bits are already zero.
if (CI->getZExtValue() > NumBits) {
unsigned LowBits = TypeWidth - CI->getZExtValue();
- if (MaskedValueIsZero(I->getOperand(0),
- APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits))
+ if (IC.MaskedValueIsZero(I->getOperand(0),
+ APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits,
+ 0, CxtI))
return true;
}
@@ -155,8 +156,9 @@ static bool CanEvaluateShifted(Value *V, unsigned NumBits, bool isLeftShift,
// profitable unless we know the and'd out bits are already zero.
if (CI->getValue().ult(TypeWidth) && CI->getZExtValue() > NumBits) {
unsigned LowBits = CI->getZExtValue() - NumBits;
- if (MaskedValueIsZero(I->getOperand(0),
- APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits))
+ if (IC.MaskedValueIsZero(I->getOperand(0),
+ APInt::getLowBitsSet(TypeWidth, NumBits) << LowBits,
+ 0, CxtI))
return true;
}
@@ -164,8 +166,9 @@ static bool CanEvaluateShifted(Value *V, unsigned NumBits, bool isLeftShift,
}
case Instruction::Select: {
SelectInst *SI = cast<SelectInst>(I);
- return CanEvaluateShifted(SI->getTrueValue(), NumBits, isLeftShift, IC) &&
- CanEvaluateShifted(SI->getFalseValue(), NumBits, isLeftShift, IC);
+ return CanEvaluateShifted(SI->getTrueValue(), NumBits, isLeftShift,
+ IC, SI) &&
+ CanEvaluateShifted(SI->getFalseValue(), NumBits, isLeftShift, IC, SI);
}
case Instruction::PHI: {
// We can change a phi if we can change all operands. Note that we never
@@ -173,7 +176,8 @@ static bool CanEvaluateShifted(Value *V, unsigned NumBits, bool isLeftShift,
// instructions with a single use.
PHINode *PN = cast<PHINode>(I);
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
- if (!CanEvaluateShifted(PN->getIncomingValue(i), NumBits, isLeftShift,IC))
+ if (!CanEvaluateShifted(PN->getIncomingValue(i), NumBits, isLeftShift,
+ IC, PN))
return false;
return true;
}
@@ -329,7 +333,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, Constant *Op1,
// See if we can propagate this shift into the input, this covers the trivial
// cast of lshr(shl(x,c1),c2) as well as other more complex cases.
if (I.getOpcode() != Instruction::AShr &&
- CanEvaluateShifted(Op0, COp1->getZExtValue(), isLeftShift, *this)) {
+ CanEvaluateShifted(Op0, COp1->getZExtValue(), isLeftShift, *this, &I)) {
DEBUG(dbgs() << "ICE: GetShiftedValue propagating shift through expression"
" to eliminate shift:\n IN: " << *Op0 << "\n SH: " << I <<"\n");
@@ -488,7 +492,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, Constant *Op1,
}
- // If the operand is an bitwise operator with a constant RHS, and the
+ // If the operand is a bitwise operator with a constant RHS, and the
// shift is the only use, we can pull it out of the shift.
if (ConstantInt *Op0C = dyn_cast<ConstantInt>(Op0BO->getOperand(1))) {
bool isValid = true; // Valid only for And, Or, Xor
@@ -691,7 +695,7 @@ Instruction *InstCombiner::visitShl(BinaryOperator &I) {
if (Value *V = SimplifyShlInst(I.getOperand(0), I.getOperand(1),
I.hasNoSignedWrap(), I.hasNoUnsignedWrap(),
- DL))
+ DL, TLI, DT, AT))
return ReplaceInstUsesWith(I, V);
if (Instruction *V = commonShiftTransforms(I))
@@ -703,14 +707,15 @@ Instruction *InstCombiner::visitShl(BinaryOperator &I) {
// If the shifted-out value is known-zero, then this is a NUW shift.
if (!I.hasNoUnsignedWrap() &&
MaskedValueIsZero(I.getOperand(0),
- APInt::getHighBitsSet(Op1C->getBitWidth(), ShAmt))) {
+ APInt::getHighBitsSet(Op1C->getBitWidth(), ShAmt),
+ 0, &I)) {
I.setHasNoUnsignedWrap();
return &I;
}
// If the shifted out value is all signbits, this is a NSW shift.
if (!I.hasNoSignedWrap() &&
- ComputeNumSignBits(I.getOperand(0)) > ShAmt) {
+ ComputeNumSignBits(I.getOperand(0), 0, &I) > ShAmt) {
I.setHasNoSignedWrap();
return &I;
}
@@ -731,7 +736,7 @@ Instruction *InstCombiner::visitLShr(BinaryOperator &I) {
return ReplaceInstUsesWith(I, V);
if (Value *V = SimplifyLShrInst(I.getOperand(0), I.getOperand(1),
- I.isExact(), DL))
+ I.isExact(), DL, TLI, DT, AT))
return ReplaceInstUsesWith(I, V);
if (Instruction *R = commonShiftTransforms(I))
@@ -760,7 +765,8 @@ Instruction *InstCombiner::visitLShr(BinaryOperator &I) {
// If the shifted-out value is known-zero, then this is an exact shift.
if (!I.isExact() &&
- MaskedValueIsZero(Op0,APInt::getLowBitsSet(Op1C->getBitWidth(),ShAmt))){
+ MaskedValueIsZero(Op0, APInt::getLowBitsSet(Op1C->getBitWidth(), ShAmt),
+ 0, &I)){
I.setIsExact();
return &I;
}
@@ -774,7 +780,7 @@ Instruction *InstCombiner::visitAShr(BinaryOperator &I) {
return ReplaceInstUsesWith(I, V);
if (Value *V = SimplifyAShrInst(I.getOperand(0), I.getOperand(1),
- I.isExact(), DL))
+ I.isExact(), DL, TLI, DT, AT))
return ReplaceInstUsesWith(I, V);
if (Instruction *R = commonShiftTransforms(I))
@@ -804,7 +810,8 @@ Instruction *InstCombiner::visitAShr(BinaryOperator &I) {
// If the shifted-out value is known-zero, then this is an exact shift.
if (!I.isExact() &&
- MaskedValueIsZero(Op0,APInt::getLowBitsSet(Op1C->getBitWidth(),ShAmt))){
+ MaskedValueIsZero(Op0,APInt::getLowBitsSet(Op1C->getBitWidth(),ShAmt),
+ 0, &I)){
I.setIsExact();
return &I;
}
@@ -812,13 +819,9 @@ Instruction *InstCombiner::visitAShr(BinaryOperator &I) {
// See if we can turn a signed shr into an unsigned shr.
if (MaskedValueIsZero(Op0,
- APInt::getSignBit(I.getType()->getScalarSizeInBits())))
+ APInt::getSignBit(I.getType()->getScalarSizeInBits()),
+ 0, &I))
return BinaryOperator::CreateLShr(Op0, Op1);
- // Arithmetic shifting an all-sign-bit value is a no-op.
- unsigned NumSignBits = ComputeNumSignBits(Op0);
- if (NumSignBits == Op0->getType()->getScalarSizeInBits())
- return ReplaceInstUsesWith(I, Op0);
-
return nullptr;
}
generated by cgit v1.1 at 2024-06-03 09:01:03 +0000