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| author | Roman Lebedev <lebedev.ri@gmail.com> | 2018-12-03 20:07:58 +0000 |
|---|---|---|
| committer | Roman Lebedev <lebedev.ri@gmail.com> | 2018-12-03 20:07:58 +0000 |
| commit | 7bf2fed16773b549f9abf6cdaa4b42f2f2644ed5 (patch) | |
| tree | 5418846be3447317399c9598f12f0c2744f84db8 /llvm/lib | |
| parent | f75f88d090c46a7fd9da3c966678e19f2c301a55 (diff) | |
| download | bcm5719-llvm-7bf2fed16773b549f9abf6cdaa4b42f2f2644ed5.tar.gz bcm5719-llvm-7bf2fed16773b549f9abf6cdaa4b42f2f2644ed5.zip | |
[InstCombine] foldICmpWithLowBitMaskedVal(): disable 2 faulty folds.
These two folds are invalid for this non-constant pattern
when the mask ends up being all-ones:
https://rise4fun.com/Alive/9au
https://rise4fun.com/Alive/UcQM
Fixes https://bugs.llvm.org/show_bug.cgi?id=39861
llvm-svn: 348181
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index 2ba1174517f..ab933d7d961 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -2955,12 +2955,16 @@ static Value *foldICmpWithLowBitMaskedVal(ICmpInst &I, // x & (-1 >> y) s>= x -> x s<= (-1 >> y) if (X != I.getOperand(1)) // X must be on RHS of comparison! return nullptr; // Ignore the other case. + if (!match(M, m_Constant())) // Can not do this fold with non-constant. + return nullptr; DstPred = ICmpInst::Predicate::ICMP_SLE; break; case ICmpInst::Predicate::ICMP_SLT: // x & (-1 >> y) s< x -> x s> (-1 >> y) if (X != I.getOperand(1)) // X must be on RHS of comparison! return nullptr; // Ignore the other case. + if (!match(M, m_Constant())) // Can not do this fold with non-constant. + return nullptr; DstPred = ICmpInst::Predicate::ICMP_SGT; break; case ICmpInst::Predicate::ICMP_SLE: |
