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

[Shih-Po Hung via llvm-commits]

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@@ -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)) {
+    // vcpop sequences, see vreduction-mask.ll.
+    if ((IID == Intrinsic::umax) || (IID == Intrinsic::smin))
+      return getArithmeticReductionCost(Instruction::Or, Ty, FMF, CostKind);
+    else
+      return getArithmeticReductionCost(Instruction::And, Ty, FMF, CostKind);
+  }
 
   // IR Reduction is composed by two vmv and one rvv reduction instruction.
-  InstructionCost BaseCost = 2;
-
-  if (CostKind == TTI::TCK_CodeSize)
-    return (LT.first - 1) + BaseCost;
-
-  unsigned VL = getEstimatedVLFor(Ty);
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arcbbb wrote:

OK! I split this off into #79103.

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