[Bug c++/118445] VEC_DUPLICATE_EXPR not handled by potential_constant_expression_1

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118445

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note the full testcase:
```
#include <arm_sve.h>

constexpr svfloat32_t f(svfloat32_t b, float a)
{
  return b + a;
}

svfloat32_t g(void)
{
  return f((svfloat32_t){1.0}, 2.0);
}
```