diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 1e0e77dde7..6441b34faa 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -1506,7 +1506,7 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) { // rights, as they sign-extend. if (ShAmt) { bool CanFold = Shift->getOpcode() != Instruction::Shr || - Shift->getType()->isUnsigned(); + Shift->getType()->isUnsigned(); 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. @@ -1519,9 +1519,11 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) { } if (CanFold) { - unsigned ShiftOp = Shift->getOpcode() == Instruction::Shl - ? Instruction::Shr : Instruction::Shl; - Constant *NewCst = ConstantExpr::get(ShiftOp, CI, ShAmt); + Constant *NewCst; + if (Shift->getOpcode() == Instruction::Shl) + NewCst = ConstantExpr::getUShr(CI, ShAmt); + else + NewCst = ConstantExpr::getShl(CI, ShAmt); // Check to see if we are shifting out any of the bits being // compared. @@ -1535,7 +1537,12 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) { return ReplaceInstUsesWith(I, ConstantBool::True); } else { I.setOperand(1, NewCst); - LHSI->setOperand(1, ConstantExpr::get(ShiftOp, AndCST,ShAmt)); + Constant *NewAndCST; + if (Shift->getOpcode() == Instruction::Shl) + NewAndCST = ConstantExpr::getUShr(AndCST, ShAmt); + else + NewAndCST = ConstantExpr::getShl(AndCST, ShAmt); + LHSI->setOperand(1, NewAndCST); LHSI->setOperand(0, Shift->getOperand(0)); WorkList.push_back(Shift); // Shift is dead. AddUsesToWorkList(I); |