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| author | Nick Lewycky <nicholas@mxc.ca> | 2008-11-02 02:41:50 +0000 |
|---|---|---|
| committer | Nick Lewycky <nicholas@mxc.ca> | 2008-11-02 02:41:50 +0000 |
| commit | 8d8acf327b97fb0165254c7d0330b4b9be9fd761 (patch) | |
| tree | 8076463688cc69f5a180ab5ab3b3931346d45927 /llvm/lib/Transforms | |
| parent | f3d9f805c79355ff3e7c46dc1cf0c0095e14bca3 (diff) | |
| download | bcm5719-llvm-8d8acf327b97fb0165254c7d0330b4b9be9fd761.tar.gz bcm5719-llvm-8d8acf327b97fb0165254c7d0330b4b9be9fd761.zip | |
Fix demanded bits analysis with srem by negative number. Based on a patch
by Richard Osborne.
llvm-svn: 58555
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index 75a1ffea6b5..3210b12cbb9 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -1274,12 +1274,12 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, APInt DemandedMask, break; case Instruction::SRem: if (ConstantInt *Rem = dyn_cast<ConstantInt>(I->getOperand(1))) { - APInt RA = Rem->getValue(); - if (RA.isPowerOf2() || (-RA).isPowerOf2()) { + APInt RA = Rem->getValue().abs(); + if (RA.isPowerOf2()) { if (DemandedMask.ule(RA)) // srem won't affect demanded bits return UpdateValueUsesWith(I, I->getOperand(0)); - APInt LowBits = RA.isStrictlyPositive() ? (RA - 1) : ~RA; + APInt LowBits = RA - 1; APInt Mask2 = LowBits | APInt::getSignBit(BitWidth); if (SimplifyDemandedBits(I->getOperand(0), Mask2, LHSKnownZero, LHSKnownOne, Depth+1)) |
