[llvm-branch-commits] [llvm] InstCombine: Introduce nsz flag on minimum/maximum in SimplifyDemandedFPClass (PR #173898)

[Yingwei Zheng via llvm-branch-commits]

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@@ -2196,9 +2196,25 @@ Value *InstCombinerImpl::SimplifyDemandedUseFPClass(Value *V,
       auto *FPOp = cast<FPMathOperator>(CI);
 
       bool ChangedFlags = false;
+      if (!FPOp->hasNoSignedZeros()) {
+        // Add NSZ flag if we know the result will not be sensitive on the sign
+        // of 0.
+        FPClassTest ZeroMask = fcZero;
+
+        if (Mode != DenormalMode::getIEEE())
+          ZeroMask |= fcSubnormal;
+
+        bool ResultNotLogical0 = (ValidResults & ZeroMask) == fcNone;
+        if (ResultNotLogical0 ||
+            ((KnownLHS.isKnownNeverLogicalNegZero(Mode) ||
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dtcxzyw wrote:

Wait for me a moment...

https://github.com/llvm/llvm-project/pull/173898