[Bug rtl-optimization/20134] [4.0 Regression] 176.gcc miscompare with -m64 after DOM change

["pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-02-22 00:55 -------
Does this testcase fail for you if so can you run a regression hunter on it for the real patch:
/* This function gets the wrong answer (63 instead of 31) when compiled
   with "-m64 -O1" on powerpc64-linux.  */

extern void abort (void);

/* From 176.gcc in SPEC CPU2000.  */
int
exact_log2_wide (x)
     register unsigned int x;
{
  unsigned int x4;
  register int log;
  if (x == 0) goto L6; else goto L0;
L0:;
  if (x != (x & -x)) goto L6; else goto L8;
L17:;
  log = 0;
L3:;
  log = log + 1;
  x4 = x4 >> 1;
  if (x4 != 0) goto L3; else goto L18;
L6:;
  log = -1;
L18:;
  return log;
L8:;
  x4 = x >> 1;
  if (x4 != 0) goto L17; else goto L19;
L19:;
  log = 0;
  goto L18;
}

int
main ()
{
    if (exact_log2_wide ((int) -2147483648) != 31)
	abort ();
    return 0;
}

Please use -O1 -fno-tree-dominator-opts as we know this is the most optimial code anyways.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|tree-optimization           |rtl-optimization
   Target Milestone|---                         |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20134