[llvm] [RISCV] Fix missing scaling by LMUL in cost model (PR #73342)

[Philip Reames via llvm-commits]

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@@ -1163,7 +1165,7 @@ RISCVTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
     auto LT = getTypeLegalizationCost(RetTy);
     if (const auto *Entry = CostTableLookup(VectorIntrinsicCostTable,
                                             ICA.getID(), LT.second))
-      return LT.first * Entry->Cost;
+      return LT.first * TLI->getLMULCost(LT.second) * Entry->Cost;
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preames wrote:

This line is incorrect.  The LMUL is already considered in the entry in the cost table.

https://github.com/llvm/llvm-project/pull/73342