[Bug tree-optimization/98254] Failure to optimize simple pattern for __builtin_convertvector

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98254

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to rguenther@suse.de from comment #2)
> Should already be handled by vectorizing the CTOR.

I've tried:

typedef int __attribute__((vector_size(16))) V;

V
foo (short *a)
{
  return (V){a[0], a[1], a[2], a[3]};
}

V
bar (int *a)
{
  return (V){a[0], a[1], a[2], a[3]};
}

and we don't do a vector (unaligned) read even in bar with -O3
-fno-tree-slp-vectorize, it is just SLP vectorization that makes it vectorize.
If we should handle foo as convertvector, we should handle bar in the same spot
as vector load from memory.