[llvm] [RISCV][CostModel] Change select cost to 2 (PR #75154)

[Philip Reames via llvm-commits]

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@@ -1401,6 +1401,11 @@ InstructionCost RISCVTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
     return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind,
                                      I);
 
+  // Select might be expanded to move and branch.
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preames wrote:

But it also might not...

I think you need to consider availability of the various select variant scalar instructions here and adjust the cost appropriately.  Consider zicond, and whichever of the scalar binmanip added min/max.  

https://github.com/llvm/llvm-project/pull/75154