[Bug c/33043] New: Miscompiled statement a[i] = (a[i]++) % x;

[gjasny at web dot de]

When the following program is compiled with gcc the output of the array-value
is 1 2 3 4 5 6. Icc and cl produce the output 1 2 3 4 1 2. If the arrray is
susbtituted by a simple scalar, the gcc output is 1 2 3 4 1 2, too.

I don't know if the statement if even valid and behavior-defined C code. If
it's not, then gcc maybe should warn somehow.

Thanks,
 Gregor

PS: This hapens with gcc-snapshot 20070720-1, too.


-- 
           Summary: Miscompiled statement a[i] = (a[i]++) % x;
           Product: gcc
           Version: 4.1.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: gjasny at web dot de
 GCC build triplet: i486-pc-linux-gnu
  GCC host triplet: i486-pc-linux-gnu
GCC target triplet: i486-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33043