[llvm] [LV] Add initial support for vectorizing literal struct return values (PR #109833)

[Benjamin Maxwell via llvm-commits]

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@@ -1506,6 +1514,8 @@ InstructionCost VPWidenRecipe::computeCost(ElementCount VF,
     return Ctx.TTI.getArithmeticInstrCost(Instruction::Mul, VectorTy,
                                           Ctx.CostKind);
   }
+  case Instruction::ExtractValue:
+    return 0;
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MacDue wrote:

I've added a new hook `getInsertExtractValueCost` rather than shoehorn it into the vector insert/extract cost functions. By default this just returns 0, but there should be enough information passed to it to implement target-specific costs in the future.   

https://github.com/llvm/llvm-project/pull/109833