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-rw-r--r--llvm/lib/Analysis/ValueTracking.cpp6
1 files changed, 5 insertions, 1 deletions
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index b98615d..412699e 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -766,12 +766,16 @@ static void computeKnownBitsFromCmp(const Value *V, const ICmpInst *Cmp,
break;
}
default:
- if (match(Cmp, m_ICmp(Pred, m_V, m_Value(A)))) {
+ const APInt *Offset = nullptr;
+ if (match(Cmp, m_ICmp(Pred, m_CombineOr(m_V, m_Add(m_V, m_APInt(Offset))),
+ m_Value(A)))) {
KnownBits RHSKnown = computeKnownBits(A, Depth + 1, QueryNoAC);
ConstantRange RHSRange =
ConstantRange::fromKnownBits(RHSKnown, Cmp->isSigned());
ConstantRange LHSRange =
ConstantRange::makeAllowedICmpRegion(Pred, RHSRange);
+ if (Offset)
+ LHSRange = LHSRange.sub(*Offset);
Known = Known.unionWith(LHSRange.toKnownBits());
}
break;