[llvm] [RISCV] Check whether plain type is supported for permutation intrinsics instead of its float type (PR #146657)

[Jim Lin via llvm-commits]

tclin914 wrote:

> Doesn't the change enable `zvfhmin` instructions even if `zvfhmin` is not enabled?

It doesn't generate the instructions from zvfhmin. 
eg.
```
%a = call <vscale x 1 x half> @llvm.riscv.vrgather.vv.nxv1f16.i64(
     <vscale x 1 x half> undef,
     <vscale x 1 x half> %0,
     <vscale x 1 x i16> %1,
     i64 %2)
```
,and its codegen:
```
vsetvli zero, a0, e16, mf4, ta, ma
vrgather.vv v10, v8, v9
vmv1r.v v8, v10
```


https://github.com/llvm/llvm-project/pull/146657