[llvm-branch-commits] [llvm] InstCombine: Infer fast math flags for sqrt (PR #176003)

[Matt Arsenault via llvm-branch-commits]

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@@ -2056,6 +2056,28 @@ inferFastMathValueFlags(FastMathFlags FMF, FPClassTest ValidResults,
   return FMF;
 }
 
+/// Apply epilog fixups to a floating-point intrinsic. See if the result can
+/// fold to a constant, or apply fast math flags.
+static Value *simplifyDemandedFPClassResult(CallInst *FPOp, FastMathFlags FMF,
+                                            FPClassTest DemandedMask,
+                                            KnownFPClass &Known,
+                                            ArrayRef<KnownFPClass> KnownSrcs) {
+  FPClassTest ValidResults = DemandedMask & Known.KnownFPClasses;
+  Constant *SingleVal = getFPClassConstant(FPOp->getType(), ValidResults,
+                                           /*IsCanonicalizing=*/true);
+  if (SingleVal)
+    return SingleVal;
+
+  FastMathFlags InferredFMF =
+      inferFastMathValueFlags(FMF, ValidResults, KnownSrcs);
+  if (InferredFMF != FMF) {
+    FPOp->setFastMathFlags(InferredFMF);
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arsenm wrote:

Missing the attribute drop 

https://github.com/llvm/llvm-project/pull/176003