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-rw-r--r--lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp6
1 files changed, 4 insertions, 2 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 08aedb3200..13653183a7 100644
--- a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -858,8 +858,8 @@ Value *InstCombiner::SimplifyShrShlDemandedBits(Instruction *Shr,
Value *VarX = Shr->getOperand(0);
Type *Ty = VarX->getType();
- APInt BitMask1(Ty->getIntegerBitWidth(), (uint64_t)-1);
- APInt BitMask2(Ty->getIntegerBitWidth(), (uint64_t)-1);
+ APInt BitMask1(APInt::getAllOnesValue(Ty->getIntegerBitWidth()));
+ APInt BitMask2(APInt::getAllOnesValue(Ty->getIntegerBitWidth()));
bool isLshr = (Shr->getOpcode() == Instruction::LShr);
BitMask1 = isLshr ? (BitMask1.lshr(ShrAmt) << ShlAmt) :
@@ -891,6 +891,8 @@ Value *InstCombiner::SimplifyShrShlDemandedBits(Instruction *Shr,
Constant *Amt = ConstantInt::get(VarX->getType(), ShrAmt - ShlAmt);
New = isLshr ? BinaryOperator::CreateLShr(VarX, Amt) :
BinaryOperator::CreateAShr(VarX, Amt);
+ if (cast<BinaryOperator>(Shr)->isExact())
+ New->setIsExact(true);
}
return InsertNewInstWith(New, *Shl);