[Bug tree-optimization/110381] [11/12/13/14 Regression] double counting for sum of structs of floating point types

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110381

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
C testcase:

struct FOO {
   double a;
   double b;
   double c;
};

double __attribute__((noipa))
sum_8_foos(const struct FOO* foos)
{
    double sum = 0;

    for (int i = 0; i < 8; ++i) {
        struct FOO foo = foos[i];

        sum += foo.c;
        sum += foo.b;
        sum += foo.a;
    }

    return sum;
}

int main()
{
  struct FOO foos[8];

  __builtin_memset (foos, 0, sizeof (foos));
  foos[0].b = 5;

  if (sum_8_foos (foos) != 5)
    __builtin_abort ();
  return 0;
}