[Bug target/82703] [7/8 Regression] Wrong addition of std::array components with -O2 -ftree-loop-vectorize -ftree-slp-vectorize (works fine with -O2)

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82703

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Reduced testcase in C, -O2 -fno-tree-sra -ftree-vectorize aborts,
-O2, or -O2 -ftree-vectorize, or -O2 -fno-tree-sra doesn't.

/* PR target/82703 */
/* { dg-do run } */
/* { dg-options "-O2 -fno-tree-sra -ftree-vectorize" } */

__attribute__((noinline, noclone)) void
compare (const double *p, const double *q)
{
  for (int i = 0; i < 3; ++i)
    if (p[i] != q[i])
      __builtin_abort ();
}

double vref[3] = { 4, 4, 4 };

int
main ()
{
  double v1[3] = { 1, 2, 3 };
  double v2[3] = { 3, 2, 1 };
  double v3[3];
  __builtin_memcpy (v3, v1, sizeof (v1));
  for (int i = 0; i < 3; ++i)
    v3[i] += v2[i];
  for (int i = 0; i < 3; ++i)
    v1[i] += v2[i];
  compare (v3, vref);
  return 0;
}