From 26c8dcc692fb2addd475446cfff24d6a4e958bca Mon Sep 17 00:00:00 2001 From: Rafael Espindola Date: Wed, 4 Apr 2012 12:51:34 +0000 Subject: Always compute all the bits in ComputeMaskedBits. This allows us to keep passing reduced masks to SimplifyDemandedBits, but know about all the bits if SimplifyDemandedBits fails. This allows instcombine to simplify cases like the one in the included testcase. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154011 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/InstCombine/InstCombineCompares.cpp | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'lib/Transforms/InstCombine/InstCombineCompares.cpp') diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp index 53089928c3..ab2987ff24 100644 --- a/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -1028,9 +1028,8 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, // of the high bits truncated out of x are known. unsigned DstBits = LHSI->getType()->getPrimitiveSizeInBits(), SrcBits = LHSI->getOperand(0)->getType()->getPrimitiveSizeInBits(); - APInt Mask(APInt::getHighBitsSet(SrcBits, SrcBits-DstBits)); APInt KnownZero(SrcBits, 0), KnownOne(SrcBits, 0); - ComputeMaskedBits(LHSI->getOperand(0), Mask, KnownZero, KnownOne); + ComputeMaskedBits(LHSI->getOperand(0), KnownZero, KnownOne); // If all the high bits are known, we can do this xform. if ((KnownZero|KnownOne).countLeadingOnes() >= SrcBits-DstBits) { -- cgit v1.2.3-70-g09d2