[Bug target/113880] New: V2SF->V2DF conversion pattern seems to be missing

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113880

            Bug ID: 113880
           Summary: V2SF->V2DF conversion pattern seems to be missing
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---
            Target: aarch64-*-*

Take:
```
void f(float *a, double *b)
{
        b[0] = a[0];
        b[1] = a[1];
}
```

This should be optimized to:
```
        ldr     d31, [x0]
        fcvt    v31.2d, v31.2s
        stp     q31, [x1]
        ret
```

But V2SF->V2DF conversion does not exist.

This is in a similar way V4HF->V4SF is missing (PR 113869).