[Bug target/116595] New: default-initialization of vfloat32m1x4_t causes ICE

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116595

            Bug ID: 116595
           Summary: default-initialization of vfloat32m1x4_t causes ICE
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---
            Target: riscv

Take this C++:
```
#include <riscv_vector.h>

void transpose4x4_ps()
{
    vfloat32m1x4_t _r = vfloat32m1x4_t();
}
```

This ICEs with:
<source>: In function 'void transpose4x4_ps()':
<source>:6:20: internal compiler error: in to_constant, at poly-int.h:592
    6 |     vfloat32m1x4_t _r = vfloat32m1x4_t();
      |                    ^~


I am not sure this is valid or not.

It also ICEs with clang.