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

[Wang Pengcheng via llvm-commits]

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@@ -1392,20 +1426,58 @@ RISCVTTIImpl::getArithmeticReductionCost(unsigned Opcode, VectorType *Ty,
     return BaseT::getArithmeticReductionCost(Opcode, Ty, FMF, CostKind);
 
   std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Ty);
-  if (Ty->getElementType()->isIntegerTy(1))
+  SmallVector<unsigned, 3> Opcodes;
+  Type *ElementTy = Ty->getElementType();
+  if (ElementTy->isIntegerTy(1)) {
     // vcpop sequences, see vreduction-mask.ll
-    return (LT.first - 1) + (ISD == ISD::AND ? 3 : 2);
+    if (ISD == ISD::AND) {
+      Opcodes = {RISCV::VMNAND_MM, RISCV::VCPOP_M};
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wangpc-pp wrote:

Same problem caused by uninitialized elements.

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