[llvm] [LV] Vectorize FMax w/o fast-math flags. (PR #146711)

[Florian Hahn via llvm-commits]

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@@ -4459,8 +4459,13 @@ bool LoopVectorizationPlanner::isCandidateForEpilogueVectorization(
     ElementCount VF) const {
   // Cross iteration phis such as reductions need special handling and are
   // currently unsupported.
-  if (any_of(OrigLoop->getHeader()->phis(),
-             [&](PHINode &Phi) { return Legal->isFixedOrderRecurrence(&Phi); }))
+  if (any_of(OrigLoop->getHeader()->phis(), [&](PHINode &Phi) {
+        return Legal->isFixedOrderRecurrence(&Phi) ||
+               (Legal->isReductionVariable(&Phi) &&
+                Legal->getReductionVars()
+                        .find(&Phi)
+                        ->second.getRecurrenceKind() == RecurKind::FMaxNoFMFs);
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fhahn wrote:

Updated to just use `lookup`, as it Kind will get default initialized to `RecurKind::None`

https://github.com/llvm/llvm-project/pull/146711