[Bug c/38687] New: wrong-code in loop optimization

[gcc-bugzilla at gcc dot gnu dot org]

        Example program works with option -O1, but not with -O2
        Problem occurs with gcc 4.3.2 and 4.4.0, but not with 4.2.4

Environment:
System: Linux andiunx 2.6.27-11-generic #1 SMP Fri Dec 19 16:29:52 UTC 2008
i686 GNU/Linux

host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: ./configure

How-To-Repeat:
        Compile the following program with
            gcc -O2 foobar.c

        extern int printf (__const char *__restrict __format, ...);

        int
        main ()
        {
          int j;

          for (j = 1; j > 0; j += j)
                printf("%d\n",j);
          return 0;
        }


------- Comment #1 from andikies at t-online dot de  2009-01-01 15:36 -------
Fix:
        Do not use -O2 option.


-- 
           Summary: wrong-code in loop optimization
           Product: gcc
           Version: 4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: andikies at t-online dot de
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38687