[Bug rtl-optimization/20290] New: Miscompilation on ppc with -Os

[jakub at gcc dot gnu dot org]

extern void abort (void);

void
check (unsigned int *l)
{
  int i;
  for (i = 0; i < 288; i++)
    if (l[i] != 7 + (i < 256 || i >= 280) + (i >= 144 && i < 256))
      abort ();
}

int
main (void)
{
  int i;
  unsigned int l[288];

  for (i = 0; i < 144; i++)
    l[i] = 8;
  for (; i < 256; i++)
    l[i] = 9;
  for (; i < 280; i++)
    l[i] = 7;
  for (; i < 288; i++)
    l[i] = 8;
  check (l);
  return 0;
}

is miscompiled on ppc with -m32 -Os.  l[256] is never set.  From initial looking
at the dumps it seems that a final value of i after the loop was miscomputed
as 257 instead of the correct 256.

-- 
           Summary: Miscompilation on ppc with -Os
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P2
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20290