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| author | Antonio Frighetto <me@antoniofrighetto.com> | 2024-06-06 08:26:40 +0200 |
|---|---|---|
| committer | Antonio Frighetto <me@antoniofrighetto.com> | 2024-06-17 21:13:52 +0200 |
| commit | c22d3917b93a6d54613d2e5b2ea4c97546144c46 (patch) | |
| tree | 7ffae85640b3d3449a92ffa7a878aa2fac39381e /llvm/lib/Analysis | |
| parent | c9549e10e9ea70428ada80a34d15afeaf5710b2d (diff) | |
| download | llvm-c22d3917b93a6d54613d2e5b2ea4c97546144c46.zip llvm-c22d3917b93a6d54613d2e5b2ea4c97546144c46.tar.gz llvm-c22d3917b93a6d54613d2e5b2ea4c97546144c46.tar.bz2 | |
[LVI][ConstantRange] Generalize mask not equal conditions handling
Extend `V & Mask != 0` for non-zero constants if satisfiable, when
retrieving constraint value information from a non-equality comparison.
Proof: https://alive2.llvm.org/ce/z/dc5BeT.
Motivating example: https://github.com/gcc-mirror/gcc/blob/master/gcc/testsuite/gcc.dg/tree-ssa/vrp76.c.
Diffstat (limited to 'llvm/lib/Analysis')
| -rw-r--r-- | llvm/lib/Analysis/LazyValueInfo.cpp | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp index 8b6e56c..aaa7baa 100644 --- a/llvm/lib/Analysis/LazyValueInfo.cpp +++ b/llvm/lib/Analysis/LazyValueInfo.cpp @@ -1188,13 +1188,10 @@ std::optional<ValueLatticeElement> LazyValueInfoImpl::getValueFromICmpCondition( return ValueLatticeElement::getRange( ConstantRange::fromKnownBits(Known, /*IsSigned*/ false)); } - // If (Val & Mask) != 0 then the value must be larger than the lowest set - // bit of Mask. - if (EdgePred == ICmpInst::ICMP_NE && !Mask->isZero() && C->isZero()) { - return ValueLatticeElement::getRange(ConstantRange::getNonEmpty( - APInt::getOneBitSet(BitWidth, Mask->countr_zero()), - APInt::getZero(BitWidth))); - } + + if (EdgePred == ICmpInst::ICMP_NE) + return ValueLatticeElement::getRange( + ConstantRange::makeMaskNotEqualRange(*Mask, *C)); } // If (X urem Modulus) >= C, then X >= C. |