[llvm] [AArch64] Add cost model for @experimental.vector.match (PR #118512)

[Paul Walker via llvm-commits]

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@@ -781,7 +781,9 @@ class TargetTransformInfoImplBase {
     default:
       break;
     case Intrinsic::experimental_vector_histogram_add:
-      // For now, we want explicit support from the target for histograms.
+    case Intrinsic::experimental_vector_match:
+      // For now, we want explicit support from the target for histograms and
+      // matches.
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paulwalker-arm wrote:

This seems excessive given you have implemented common lowering code where I think the base cost is effectively:

`(cost_of_extract_elt+cost_of_vector_splat+cost_of_vector_cmp+)*number_of_needle_elements`.

https://github.com/llvm/llvm-project/pull/118512