[llvm] [RISCV][TTI] Add cost model for ROTL/ROTR (PR #170824)

[Craig Topper via llvm-commits]

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@@ -1559,6 +1559,20 @@ RISCVTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
     }
     break;
   }
+  case Intrinsic::fshl:
+  case Intrinsic::fshr: {
+    // Funnel-shifts are ROTL/ROTR when the first and second operand are equal.
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topperc wrote:

Do we need to check `ICA.getArgs().empty()` like AArch64?                                         
   

https://github.com/llvm/llvm-project/pull/170824