[Bug target/124174] aarch64: NEON vadd should be well-defined on overflow

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124174

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
The x86 backend uses unsigned types in intrinsics when open-coding:

extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__,
__artificial__))
_mm_add_epi64 (__m128i __A, __m128i __B)
{ 
  return (__m128i) ((__v2du)__A + (__v2du)__B);
}