[Bug rtl-optimization/64286] Redundant extend removal ignores vector element type

["jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64286

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-01-09
     Ever confirmed|0                           |1

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Reduced testcase (-O2 -mavx2):
#include <string.h>
#include <stdlib.h>
#include <x86intrin.h>

__m128i v;
__m256i w;

__attribute__((noinline, noclone)) void
foo (__m128i *p, __m128i *q)
{
  __m128i a = _mm_loadu_si128 (p);
  __m128i b = _mm_xor_si128 (a, v);
  w = _mm256_cvtepu8_epi16 (a);
  *q = b;
}

int
main ()
{
  v = _mm_set1_epi8 (0x40);
  __m128i c = _mm_set_epi8 (16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2,
1);
  __m128i d;
  foo (&c, &d);
  __m128i e = _mm_set_epi8 (0x50, 0x4f, 0x4e, 0x4d, 0x4c, 0x4b, 0x4a, 0x49,
                0x48, 0x47, 0x46, 0x45, 0x44, 0x43, 0x42, 0x41);
  __m256i f = _mm256_set_epi16 (16, 15, 14, 13, 12, 11, 10, 9,
                8, 7, 6, 5, 4, 3, 2, 1);
  if (memcmp (&w, &f, sizeof (w)) != 0
      || memcmp (&d, &e, sizeof (d)) != 0)
    abort ();
  return 0;
}