[llvm] [RISCV] Use lookup tables to find CVTFOpc (PR #88742)

[Pengcheng Wang via llvm-commits]

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@@ -3585,7 +3585,7 @@ multiclass VPseudoConversion<VReg RetClass,
                              int sew = 0,
                              int TargetConstraintType = 1> {
   defvar suffix = !if(sew, "_" # MInfo.MX # "_E" # sew, "_" # MInfo.MX);
-  let VLMul = MInfo.value in {
+  let VLMul = MInfo.value, SEW=sew in {
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wangpc-pp wrote:

Not related to this patch, but can you check if there are more misses of setting `SEW`?

https://github.com/llvm/llvm-project/pull/88742