[llvm] [AArch64] Avoid generating LDAPUR on certain cores (PR #124274)

[Sjoerd Meijer via llvm-commits]

================
@@ -809,6 +809,9 @@ def FeatureUseFixedOverScalableIfEqualCost: SubtargetFeature<"use-fixed-over-sca
   "UseFixedOverScalableIfEqualCost", "true",
   "Prefer fixed width loop vectorization over scalable if the cost-model assigns equal costs">;
 
+def FeatureAvoidLDAPUR: SubtargetFeature<"avoid-ldapur", "AvoidLDAPUR", "true",
----------------
sjoerdmeijer wrote:

Nit: maybe add a comment that we want to avoid this instruction for performance reasons on some cores?

https://github.com/llvm/llvm-project/pull/124274