[llvm] [VPlan] Extract reverse operation for reverse accesses (PR #146525)

[Mel Chen via llvm-commits]

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@@ -1541,6 +1541,12 @@ RISCVTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
                           cast<VectorType>(ICA.getArgTypes()[0]), {}, CostKind,
                           0, cast<VectorType>(ICA.getReturnType()));
   }
+  case Intrinsic::experimental_vp_reverse: {
+    return getShuffleCost(TTI::SK_Reverse,
+                          cast<VectorType>(ICA.getReturnType()),
+                          cast<VectorType>(ICA.getArgTypes()[0]), {}, CostKind,
+                          0, cast<VectorType>(ICA.getReturnType()));
+  }
   }
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Mel-Chen wrote:

Sure, thanks! This part of the cost model implementation is just to avoid the cost being Invalid. It definitely should be implemented as a separate patch.

https://github.com/llvm/llvm-project/pull/146525