[llvm] [AArch64] Improve cost model for legal subvec insert/extract (PR #81135)

[David Sherwood via llvm-commits]

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@@ -568,6 +568,32 @@ AArch64TTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
     }
     return Cost;
   }
+  case Intrinsic::vector_extract: {
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david-arm wrote:

I think it would be good to have proper cost model test cases in llvm/test/Analysis/CostModel/AArch64. You can look at existing examples as a guide.

https://github.com/llvm/llvm-project/pull/81135