[llvm] [TTI][AArch64] Add preferFixedIfEqualToScalable hook (PR #95818)

[Sjoerd Meijer via llvm-commits]

================
@@ -244,6 +244,9 @@ def FeatureExperimentalZeroingPseudos
 def FeatureUseScalarIncVL : SubtargetFeature<"use-scalar-inc-vl",
   "UseScalarIncVL", "true", "Prefer inc/dec over add+cnt">;
 
+def FeatureUseFixedIfEqualToScalable : SubtargetFeature<"use-fixed-if-equal-to-scalable",
----------------
sjoerdmeijer wrote:

Thanks for the naming suggesting, I was struggling with the name, will change it to `FeatureUseFixedOverScalableIfEqualCost`.

https://github.com/llvm/llvm-project/pull/95818