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author | Nikita Popov <npopov@redhat.com> | 2023-05-17 17:12:32 +0200 |
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committer | Nikita Popov <npopov@redhat.com> | 2023-05-17 17:14:54 +0200 |
commit | 4ca30ded4f07b192b8a8bed069400f9d6b85a792 (patch) | |
tree | 8d09b0115b085be60db0c331f20307cf79e09618 | |
parent | 2f3ac28cb2f7fc24c6ff742af571b58419c0adaa (diff) | |
download | llvm-4ca30ded4f07b192b8a8bed069400f9d6b85a792.tar.gz |
[InstCombine] Use KnownBits::urem() helper
This provides more precise results than the ad-hoc implementation.
Noticed while trying to add a consistency assertion.
To be honest I'm not sure why this code exists at all -- the
recursive calls are done with all bits demanded, so this should
be equivalent to just using the default case.
-rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp index 0d0522a18349..c00bc74191a0 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp @@ -855,14 +855,12 @@ Value *InstCombinerImpl::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, break; } case Instruction::URem: { - KnownBits Known2(BitWidth); APInt AllOnes = APInt::getAllOnes(BitWidth); - if (SimplifyDemandedBits(I, 0, AllOnes, Known2, Depth + 1) || - SimplifyDemandedBits(I, 1, AllOnes, Known2, Depth + 1)) + if (SimplifyDemandedBits(I, 0, AllOnes, LHSKnown, Depth + 1) || + SimplifyDemandedBits(I, 1, AllOnes, RHSKnown, Depth + 1)) return I; - unsigned Leaders = Known2.countMinLeadingZeros(); - Known.Zero = APInt::getHighBitsSet(BitWidth, Leaders) & DemandedMask; + Known = KnownBits::urem(LHSKnown, RHSKnown); break; } case Instruction::Call: { |