[llvm] [AArch64] Avoid single-element vector fp converts in streaming[-compatible] functions (PR #112213)

[Sander de Smalen via llvm-commits]

================
@@ -247,6 +247,11 @@ def HasSMEF16F16orSMEF8F16
 def HasNEONandIsStreamingSafe
     : Predicate<"Subtarget->hasNEON()">,
       AssemblerPredicateWithAll<(any_of FeatureNEON), "neon">;
+// A subset of NEON instructions legal in Streaming SVE mode with +sme2p2.
+// TODO: Change to check for hasSME2p2() once FEAT_SME2p2 is implemented.
+def HasNEONandIsSME2p2StreamingSafe
----------------
sdesmalen-arm wrote:

nit: At the moment the predicate does not do what the name suggests. Could you use the existing `HasNEON` predicate and instead add a TODO to the places where `HasNEONandIsStreamingSafe` was used incorrectly?

https://github.com/llvm/llvm-project/pull/112213