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Fix PR577 and testcase InstCombine/2005-06-15-ShiftSetCCCrash.ll.

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Do not perform undefined out of range shifts.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22217 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-06-15 20:53:31 +00:00
parent 7833b44f6a
commit e17a128a55
1 changed files with 16 additions and 2 deletions
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18
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -2560,6 +2560,14 @@ Instruction *InstCombiner::visitSetCondInst(SetCondInst &I) {
default: break;
case Instruction::SetEQ:
case Instruction::SetNE: {
unsigned TypeBits = CI->getType()->getPrimitiveSizeInBits();
// Check that the shift amount is in range. If not, don't perform
// undefined shifts. When the shift is visited it will be
// simplified.
if (ShAmt->getValue() >= TypeBits)
break;
// If we are comparing against bits always shifted out, the
// comparison cannot succeed.
Constant *Comp =
@ -2573,7 +2581,6 @@ Instruction *InstCombiner::visitSetCondInst(SetCondInst &I) {
if (LHSI->hasOneUse()) {
// Otherwise strength reduce the shift into an and.
unsigned ShAmtVal = (unsigned)ShAmt->getValue();
unsigned TypeBits = CI->getType()->getPrimitiveSizeInBits();
uint64_t Val = (1ULL << (TypeBits-ShAmtVal))-1;
Constant *Mask;
@ -2603,6 +2610,14 @@ Instruction *InstCombiner::visitSetCondInst(SetCondInst &I) {
default: break;
case Instruction::SetEQ:
case Instruction::SetNE: {
// Check that the shift amount is in range. If not, don't perform
// undefined shifts. When the shift is visited it will be
// simplified.
unsigned TypeBits = ShAmt->getType()->getPrimitiveSizeInBits();
if (ShAmt->getValue() >= TypeBits)
break;
// If we are comparing against bits always shifted out, the
// comparison cannot succeed.
Constant *Comp =
@ -2623,7 +2638,6 @@ Instruction *InstCombiner::visitSetCondInst(SetCondInst &I) {
Constant *Mask;
if (CI->getType()->isUnsigned()) {
unsigned TypeBits = CI->getType()->getPrimitiveSizeInBits();
Val &= ~0ULL >> (64-TypeBits);
Mask = ConstantUInt::get(CI->getType(), Val);
} else {