From f7d0d163c5962a51cf9eb32db093b5d1fd8114fa Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sat, 23 Jan 2010 23:31:46 +0000 Subject: [PATCH] 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 --- lib/Transforms/InstCombine/InstCombineShifts.cpp | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/Transforms/InstCombine/InstCombineShifts.cpp b/lib/Transforms/InstCombine/InstCombineShifts.cpp index 9dd60dd4a25..836bda36937 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(Op1)) if (IntrinsicInst *II = dyn_cast(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()); } -- 2.34.1