[llvm] [LoopUtils] Consider fast-math flags derived from function attribute when getting recurrence identity (PR #162630)

[Matt Arsenault via llvm-commits]

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@@ -998,11 +998,7 @@ bool RecurrenceDescriptor::isReductionPHI(PHINode *Phi, Loop *TheLoop,
                                           ScalarEvolution *SE) {
   BasicBlock *Header = TheLoop->getHeader();
   Function &F = *Header->getParent();
-  FastMathFlags FMF;
-  FMF.setNoNaNs(
-      F.getFnAttribute("no-nans-fp-math").getValueAsBool());
-  FMF.setNoSignedZeros(
-      F.getFnAttribute("no-signed-zeros-fp-math").getValueAsBool());
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arsenm wrote:

This should be deleted without replacement 

https://github.com/llvm/llvm-project/pull/162630