[llvm] [AArch64][CostModel] Lower cost of dupq (SVE2.1) (PR #144918)

[Sander de Smalen via llvm-commits]

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@@ -5583,6 +5583,26 @@ InstructionCost AArch64TTIImpl::getShuffleCost(
     Kind = TTI::SK_PermuteSingleSrc;
   }
 
+  // Segmented shuffle matching.
+  if (ST->hasSVE2p1() && CostKind == TTI::TCK_RecipThroughput &&
+      Kind == TTI::SK_PermuteSingleSrc && isa<FixedVectorType>(Tp) &&
+      Tp->getPrimitiveSizeInBits().isKnownMultipleOf(128)) {
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sdesmalen-arm wrote:

nit: please use `AArch64::SVEBitsPerBlock` instead of hard-coding 128.

https://github.com/llvm/llvm-project/pull/144918