[Bug tree-optimization/43012] New: wrong code for -floop-strip-mine in 453.povray

[janis at gcc dot gnu dot org]

SPEC CPU2006 test 453.povray is miscompiled by GCC mainline on powerpc64-linux
for "-O2 -floop-strip-line" with either -m32 or -m64.  Here's the function that
is miscompiled; I'll attach a complete executable testcase:

----------------------------------------------------
void
pre_init_tokenizer ()
{
  int i;

  for (i = 0; i < LAST_TOKEN; i++)
    {
      Table[i] = i;
      if (i < FLOAT_FUNCT_TOKEN)
        Table[i] = FLOAT_FUNCT_TOKEN;
      else
        {
          if (i < VECTOR_FUNCT_TOKEN)
            Table[i] = VECTOR_FUNCT_TOKEN;
          else
            {
              if (i < COLOUR_KEY_TOKEN)
                Table[i] = COLOUR_KEY_TOKEN;
            }
        }
    }
}
----------------------------------------------------

Array elements 51-63 and 89-101 are not assigned values when the code is
compiled with "-O2 -floop-strip-mine".

The testcase (and 453.povray) work with GCC 4.4.2 with those options, so this
is a regression in GCC 4.5.  The failure starts with this patch:

    http://gcc.gnu.org/viewcvs?view=rev&rev=154637

    r154637 | spop | 2009-11-25 05:30:35 +0000 (Wed, 25 Nov 2009)


-- 
           Summary: wrong code for -floop-strip-mine in 453.povray
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: janis at gcc dot gnu dot org
GCC target triplet: powerpc64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43012