[llvm] [RISCV][TTI] Refine the cost of FCmp (PR #88833)

[Shih-Po Hung via llvm-commits]

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@@ -22,14 +22,14 @@ define void @select() {
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 5 for instruction: %15 = select i1 undef, <vscale x 2 x i1> undef, <vscale x 2 x i1> undef
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 5 for instruction: %16 = select i1 undef, <vscale x 4 x i1> undef, <vscale x 4 x i1> undef
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 5 for instruction: %17 = select i1 undef, <vscale x 8 x i1> undef, <vscale x 8 x i1> undef
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 10 for instruction: %18 = select i1 undef, <vscale x 16 x i1> undef, <vscale x 16 x i1> undef
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 20 for instruction: %19 = select i1 undef, <vscale x 32 x i1> undef, <vscale x 32 x i1> undef
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %18 = select i1 undef, <vscale x 16 x i1> undef, <vscale x 16 x i1> undef
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 14 for instruction: %19 = select i1 undef, <vscale x 32 x i1> undef, <vscale x 32 x i1> undef
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arcbbb wrote:

This is affected by the assignment of a cost of 1 to mask operations, because `<vscale x N x i1>` translates directly into `<vscale x N x i8>` in `RISCVTargetLowering::getLMUL(MVT)`

https://github.com/llvm/llvm-project/pull/88833