From 19b57f55aa5952bc6c79e969d0a878481f4a824c Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Wed, 15 Jun 2005 20:53:31 +0000 Subject: Fix PR577 and testcase InstCombine/2005-06-15-ShiftSetCCCrash.ll. Do not perform undefined out of range shifts. llvm-svn: 22217 --- llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index 53ee6ca01fb..02438202dc5 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -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 { -- cgit v1.2.3