From 5f70c2e934c8cf7814fc047f4824ac89b35dd72d Mon Sep 17 00:00:00 2001 From: Shuxin Yang Date: Wed, 12 Dec 2012 00:29:03 +0000 Subject: - Fix a problematic way in creating all-the-1 APInt. - Propagate "exact" bit of [l|a]shr instruction. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169942 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp') 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(Shr)->isExact()) + New->setIsExact(true); } return InsertNewInstWith(New, *Shl); -- cgit v1.2.3-70-g09d2