[llvm] [LV] Convert uniform-address unmasked scatters to scalar store. (PR #166114)

[Elvis Wang via llvm-commits]

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@@ -1208,6 +1208,7 @@ InstructionCost VPInstruction::computeCost(ElementCount VF,
                                   I32Ty, {Arg0Ty, I32Ty, I1Ty});
     return Ctx.TTI.getIntrinsicInstrCost(Attrs, Ctx.CostKind);
   }
+  case VPInstruction::ExtractLastLanePerPart:
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ElvisWang123 wrote:

Add this to prevent tests changes in the `RISCV/uniform-load-store.ll`.
Otherwise it will choose smaller VF which uses extract-last-lane-per-part and its free.

https://github.com/llvm/llvm-project/pull/166114