[Bug tree-optimization/113787] [12/13/14 Regression] Wrong code at -O with ipa-modref on aarch64

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113787

--- Comment #12 from Alex Coplan <acoplan at gcc dot gnu.org> ---
Here is an alternative testcase that also fails in the same way on the GCC 12
and 13 branches:

void foo(int x, int y, int z, int d, int *buf)
{
  for(int i = z; i < y-z; ++i)
    for(int j = 0; j < d; ++j)
      buf[i*x+(z-j-1)] = buf[i*x+(z+j)];
}

void bar(int x, int y, int z, int d, int *buf)
{
  for(int i = 0; i < d; ++i)
    for(int j = z; j < x-z; ++j)
      buf[j+(z-i-1)*x] = buf[j+(z+i)*x];
}

__attribute__((noipa))
void baz(int x, int y, int d, int *buf)
{
  foo(x, y, 0, d, buf);
  bar(x, y, 0, d, buf);
}

int main(void)
{
  int a[] = { 1, 2, 3 };
  baz (1, 2, 1, a+1);
  /* buf = a+1.
     foo does:
     buf[-1] = buf[0]; // { 2, 2, 3 }
     buf[0] = buf[1];  // { 2, 3, 3 }

     bar does:
     buf[-1] = buf[0]; // { 3, 3, 3 }  */
  for (int i = 0; i < 2; i++)
    if (a[i] != 3)
      __builtin_abort ();
}