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| author | Chris Lattner <sabre@nondot.org> | 2010-01-23 23:31:46 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2010-01-23 23:31:46 +0000 |
| commit | f7d0d163c5962a51cf9eb32db093b5d1fd8114fa (patch) | |
| tree | d1400a271b5ae1a625b5a2d72fcd58ff08722cf6 | |
| parent | 44540740aeafcae8c5d030000e7fd468f01d0da9 (diff) | |
| download | llvm-f7d0d163c5962a51cf9eb32db093b5d1fd8114fa.tar.gz llvm-f7d0d163c5962a51cf9eb32db093b5d1fd8114fa.tar.bz2 llvm-f7d0d163c5962a51cf9eb32db093b5d1fd8114fa.tar.xz | |
fix a potential overflow issue Eli pointed out.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94336 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineShifts.cpp | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineShifts.cpp b/lib/Transforms/InstCombine/InstCombineShifts.cpp index 9dd60dd4a2..836bda3693 100644 --- a/lib/Transforms/InstCombine/InstCombineShifts.cpp +++ b/lib/Transforms/InstCombine/InstCombineShifts.cpp @@ -394,16 +394,16 @@ Instruction *InstCombiner::visitLShr(BinaryOperator &I) { if (ConstantInt *Op1C = dyn_cast<ConstantInt>(Op1)) if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op0)) { + unsigned BitWidth = Op0->getType()->getScalarSizeInBits(); // ctlz.i32(x)>>5 --> zext(x == 0) // cttz.i32(x)>>5 --> zext(x == 0) // ctpop.i32(x)>>5 --> zext(x == -1) if ((II->getIntrinsicID() == Intrinsic::ctlz || II->getIntrinsicID() == Intrinsic::cttz || II->getIntrinsicID() == Intrinsic::ctpop) && - (1ULL << Op1C->getZExtValue()) == - Op0->getType()->getScalarSizeInBits()) { + isPowerOf2_32(BitWidth) && Log2_32(BitWidth) == Op1C->getZExtValue()){ bool isCtPop = II->getIntrinsicID() == Intrinsic::ctpop; - Constant *RHS = ConstantInt::getSigned(Op0->getType(), isCtPop ? -1 : 0); + Constant *RHS = ConstantInt::getSigned(Op0->getType(), isCtPop ? -1:0); Value *Cmp = Builder->CreateICmpEQ(II->getOperand(1), RHS); return new ZExtInst(Cmp, II->getType()); } |