[llvm] Vectorize: Support fminimumnum and fmaximumnum (PR #131781)

[Matt Arsenault via llvm-commits]

================
@@ -2776,6 +2776,12 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
       }
       return Cost;
     }
+    case Intrinsic::maximumnum:
+    case Intrinsic::minimumnum: {
+      if (TLI->isOperationLegalOrPromote(llvm::ISD::FMAXNUM_IEEE, LT.second))
+        return LT.first * 3;
----------------
arsenm wrote:

Can you comment on the expansion here? 

We can't have a dedicated test for FMAXNUM_IEEE. As implemented, it's a backend only implementation detail. However the langref now states it's the same as llvm.maxnum, so eventually this will be equivalent 

https://github.com/llvm/llvm-project/pull/131781