[llvm] [RISCV][CostModel] Updates reduction and shuffle cost (PR #77342)

[Philip Reames via llvm-commits]

================
@@ -1358,19 +1358,51 @@ RISCVTTIImpl::getMinMaxReductionCost(Intrinsic::ID IID, VectorType *Ty,
     return BaseT::getMinMaxReductionCost(IID, Ty, FMF, CostKind);
 
   std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Ty);
-  if (Ty->getElementType()->isIntegerTy(1))
-    // vcpop sequences, see vreduction-mask.ll.  umax, smin actually only
-    // cost 2, but we don't have enough info here so we slightly over cost.
-    return (LT.first - 1) + 3;
+  if (Ty->getElementType()->isIntegerTy(1)) {
----------------
preames wrote:

If you separate this as it's own patch, should be easy to review.

https://github.com/llvm/llvm-project/pull/77342