diff options
| author | Rafael Espindola <rafael.espindola@gmail.com> | 2012-04-04 12:51:34 +0000 |
|---|---|---|
| committer | Rafael Espindola <rafael.espindola@gmail.com> | 2012-04-04 12:51:34 +0000 |
| commit | 26c8dcc692fb2addd475446cfff24d6a4e958bca (patch) | |
| tree | b71cb0d781e2735397c728f276f14ea63780d04c /lib/Transforms/InstCombine/InstCombineCompares.cpp | |
| parent | 00b73a5e443d49d68f59a5fb517e940842423ae6 (diff) | |
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
Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineCompares.cpp')
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineCompares.cpp | 3 |
1 files changed, 1 insertions, 2 deletions
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) { |