[llvm-commits] CVS: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
Zhou Sheng
zhousheng00 at gmail.com
Fri Mar 30 10:20:56 PDT 2007
Changes in directory llvm/lib/Transforms/Scalar:
InstructionCombining.cpp updated: 1.711 -> 1.712
---
Log message:
Make sure the use of ConstantInt::getZExtValue() for shift amount safe.
---
Diffs of the changes: (+20 -18)
InstructionCombining.cpp | 38 ++++++++++++++++++++------------------
1 files changed, 20 insertions(+), 18 deletions(-)
Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.711 llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.712
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.711 Fri Mar 30 04:29:48 2007
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Fri Mar 30 12:20:39 2007
@@ -1354,7 +1354,7 @@
}
if (ConstantInt *SA = dyn_cast<ConstantInt>(I->getOperand(1))) {
- unsigned ShiftAmt = SA->getZExtValue();
+ uint32_t ShiftAmt = SA->getLimitedValue(BitWidth);
// Signed shift right.
APInt DemandedMaskIn(DemandedMask.shl(ShiftAmt));
@@ -2095,12 +2095,12 @@
// -(X >>u 31) -> (X >>s 31)
// -(X >>s 31) -> (X >>u 31)
- if (C->isNullValue()) {
+ if (C->isZero()) {
if (BinaryOperator *SI = dyn_cast<BinaryOperator>(Op1))
if (SI->getOpcode() == Instruction::LShr) {
if (ConstantInt *CU = dyn_cast<ConstantInt>(SI->getOperand(1))) {
// Check to see if we are shifting out everything but the sign bit.
- if (CU->getZExtValue() ==
+ if (CU->getLimitedValue(SI->getType()->getPrimitiveSizeInBits()) ==
SI->getType()->getPrimitiveSizeInBits()-1) {
// Ok, the transformation is safe. Insert AShr.
return BinaryOperator::create(Instruction::AShr,
@@ -2111,7 +2111,7 @@
else if (SI->getOpcode() == Instruction::AShr) {
if (ConstantInt *CU = dyn_cast<ConstantInt>(SI->getOperand(1))) {
// Check to see if we are shifting out everything but the sign bit.
- if (CU->getZExtValue() ==
+ if (CU->getLimitedValue(SI->getType()->getPrimitiveSizeInBits()) ==
SI->getType()->getPrimitiveSizeInBits()-1) {
// Ok, the transformation is safe. Insert LShr.
return BinaryOperator::createLShr(
@@ -4789,7 +4789,8 @@
if (!CanFold) {
// To test for the bad case of the signed shr, see if any
// of the bits shifted in could be tested after the mask.
- int ShAmtVal = Ty->getPrimitiveSizeInBits()-ShAmt->getZExtValue();
+ uint32_t TyBits = Ty->getPrimitiveSizeInBits();
+ int ShAmtVal = TyBits - ShAmt->getLimitedValue(TyBits);
if (ShAmtVal < 0) ShAmtVal = 0; // Out of range shift.
uint32_t BitWidth = AndTy->getPrimitiveSizeInBits();
@@ -4883,7 +4884,7 @@
if (LHSI->hasOneUse()) {
// Otherwise strength reduce the shift into an and.
- unsigned ShAmtVal = (unsigned)ShAmt->getZExtValue();
+ uint32_t ShAmtVal = (uint32_t)ShAmt->getLimitedValue(TypeBits);
uint64_t Val = (1ULL << (TypeBits-ShAmtVal))-1;
Constant *Mask = ConstantInt::get(CI->getType(), Val);
@@ -4926,7 +4927,7 @@
}
if (LHSI->hasOneUse() || CI->isNullValue()) {
- unsigned ShAmtVal = (unsigned)ShAmt->getZExtValue();
+ uint32_t ShAmtVal = (uint32_t)ShAmt->getLimitedValue(TypeBits);
// Otherwise strength reduce the shift into an and.
APInt Val(APInt::getHighBitsSet(TypeBits, TypeBits - ShAmtVal));
@@ -5658,7 +5659,7 @@
BinaryOperator::create(Op0BO->getOpcode(), YS, V1,
Op0BO->getOperand(1)->getName());
InsertNewInstBefore(X, I); // (X + (Y << C))
- uint32_t Op1Val = Op1->getZExtValue();
+ uint32_t Op1Val = Op1->getLimitedValue(TypeBits);
return BinaryOperator::createAnd(X, ConstantInt::get(
APInt::getHighBitsSet(TypeBits, TypeBits-Op1Val)));
}
@@ -5697,7 +5698,7 @@
BinaryOperator::create(Op0BO->getOpcode(), V1, YS,
Op0BO->getOperand(0)->getName());
InsertNewInstBefore(X, I); // (X + (Y << C))
- uint32_t Op1Val = Op1->getZExtValue();
+ uint32_t Op1Val = Op1->getLimitedValue(TypeBits);
return BinaryOperator::createAnd(X, ConstantInt::get(
APInt::getHighBitsSet(TypeBits, TypeBits-Op1Val)));
}
@@ -6084,8 +6085,9 @@
// If we are truncating the result of this SHL, and if it's a shift of a
// constant amount, we can always perform a SHL in a smaller type.
if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
- if (Ty->getBitWidth() < OrigTy->getBitWidth() &&
- CI->getZExtValue() < Ty->getBitWidth())
+ uint32_t BitWidth = Ty->getBitWidth();
+ if (BitWidth < OrigTy->getBitWidth() &&
+ CI->getLimitedValue(BitWidth) < BitWidth)
return CanEvaluateInDifferentType(I->getOperand(0), Ty,NumCastsRemoved);
}
break;
@@ -6095,12 +6097,12 @@
// lshr iff we know that the bits we would otherwise be shifting in are
// already zeros.
if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
- uint32_t BitWidth = OrigTy->getBitWidth();
- if (Ty->getBitWidth() < BitWidth &&
+ uint32_t OrigBitWidth = OrigTy->getBitWidth();
+ uint32_t BitWidth = Ty->getBitWidth();
+ if (BitWidth < OrigBitWidth &&
MaskedValueIsZero(I->getOperand(0),
- APInt::getAllOnesValue(BitWidth) &
- APInt::getAllOnesValue(Ty->getBitWidth()).zextOrTrunc(BitWidth).flip())
- && CI->getZExtValue() < Ty->getBitWidth()) {
+ APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth)) &&
+ CI->getLimitedValue(BitWidth) < BitWidth) {
return CanEvaluateInDifferentType(I->getOperand(0), Ty, NumCastsRemoved);
}
}
@@ -6396,7 +6398,7 @@
// simplifications.
if (DestBitSize < SrcBitSize &&
isa<ConstantInt>(Op1)) {
- unsigned ShiftAmt = cast<ConstantInt>(Op1)->getZExtValue();
+ uint32_t ShiftAmt = cast<ConstantInt>(Op1)->getLimitedValue(SrcBitSize);
if (SrcBitSize > ShiftAmt && SrcBitSize-ShiftAmt >= DestBitSize) {
// Insert the new logical shift right.
return BinaryOperator::createLShr(Op0, Op1);
@@ -6486,7 +6488,7 @@
// We can shrink lshr to something smaller if we know the bits shifted in
// are already zeros.
if (ConstantInt *ShAmtV = dyn_cast<ConstantInt>(SrcI->getOperand(1))) {
- unsigned ShAmt = ShAmtV->getZExtValue();
+ uint32_t ShAmt = ShAmtV->getLimitedValue(SrcBitWidth);
// Get a mask for the bits shifting in.
APInt Mask(APInt::getLowBitsSet(SrcBitWidth, ShAmt).shl(DestBitWidth));
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