[Bug tree-optimization/48616] -ftree-vectorize -mxop miscompiles right shift

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48616

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-04-15 
16:49:36 UTC ---
extern void abort (void);
int a[4] __attribute__((aligned (32)));
int b[4] __attribute__((aligned (32)));
int c[4] __attribute__((aligned (32)));
int d[4] __attribute__((aligned (32)));
int e[4] __attribute__((aligned (32)));

__attribute__((noinline, noclone))
void
foo (int i)
{
  a[0] = b[0] << c[0];
  a[1] = b[1] << c[1];
  a[2] = b[2] << c[2];
  a[3] = b[3] << c[3];
  if (i)
    {
      d[0] = e[0] >> c[0];
      d[1] = e[1] >> c[1];
      d[2] = e[2] >> c[2];
      d[3] = e[3] >> c[3];
    }
}

int
main ()
{
  int i;
  int *t;
  for (i = 0; i < 4; i++)
    {
      b[i] = 32;
      c[i] = i;
      e[i] = 32;
    }
  asm volatile ("" : : "r" (b) : "memory");
  asm volatile ("" : : "r" (c) : "memory");
  asm volatile ("" : "=r" (t) : "0" (d) : "memory");
  foo (t != 0);
  for (i = 0; i < 4; i++)
    if (a[i] != (32 << i) || d[i] != (32 >> i))
      abort ();
  return 0;
}

is reduced testcase for -O2 -ftree-vectorize -mxop.  I might try to fix this on
Monday, unless Ira beats me to do it.