[Bug tree-optimization/54981] New: [4.8 Regression] Different code generated with / without `-g'

["d.g.gorbachev at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54981

             Bug #: 54981
           Summary: [4.8 Regression] Different code generated with /
                    without `-g'
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: d.g.gorbachev@gmail.com


Appeared between 20120513 (r187445) and 20120902 (r190863):

$ cat > 1.c
extern void bar(unsigned *, char *);

void foo(char *s)
{
  unsigned i;
  char t[2];

  bar(&i, t);

  for (i = 0; i < 2; i++)
    s[i] = t[i];
}
^D
$ gcc -S -O3 -fcompare-debug 1.c
gcc: error: 1.c: -fcompare-debug failure (length)

Also fails with `-O -ftree-loop-distribute-patterns'.