[llvm] [InstCombine] Improve folding of `icmp pred (and X, Mask/~Mask), Y)` (PR #81562)
Yingwei Zheng via llvm-commits
llvm-commits at lists.llvm.org
Mon Feb 12 22:06:45 PST 2024
================
@@ -4068,11 +4068,117 @@ Instruction *InstCombinerImpl::foldSelectICmp(ICmpInst::Predicate Pred,
return nullptr;
}
+// Returns whether V is a Mask ((X + 1) & X == 0) or ~Mask (-Pow2OrZero)
+static bool isMaskOrZero(const Value *V, bool Not, const SimplifyQuery &Q,
+ unsigned Depth = 0) {
+ if (Not ? match(V, m_NegatedPower2OrZero()) : match(V, m_LowBitMaskOrZero()))
+ return true;
+ if (V->getType()->getScalarSizeInBits() == 1)
+ return true;
+ if (Depth++ >= MaxAnalysisRecursionDepth)
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dtcxzyw wrote:
What is the compile-time impact of this patch?
https://github.com/llvm/llvm-project/pull/81562
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