[Bug middle-end/36902] Array bound warning with dead code after optimization

["hjl dot tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #12 from hjl dot tools at gmail dot com  2008-07-23 01:23 -------
(In reply to comment #11)
> Thanks. Actually, I think the experiment would be more meaningful if you could
> put also the equivalent of your main (a calling function, that is) inside the
> header, because in your testcase the warning is triggered inside the main, not
> in foo.
> 

Same:

[hjl@gnu-6 tmp]$ cat y.h
#pragma GCC system_header
static inline unsigned char *
foo(unsigned char * to, const unsigned char * from, int n)
{
    switch ( n )
    {
    case 3:
      *to = *from;
        break;
    case 5:
        to[4] = from [4];
        break;
    }
    return to;
}

struct {
    int    size_of_select;
    unsigned char pcr_select[4];
} sel;

static int
bar (void)
{
    static unsigned char buf[64];

    sel.size_of_select = 3;
    foo(buf, sel.pcr_select, sel.size_of_select);

    return 1;
}
[hjl@gnu-6 tmp]$ cat y.c
#include <y.h>

int
main ()
{
  return bar ();
}
[hjl@gnu-6 tmp]$ gcc -Wall -O2 -c y.c -Werror -I.
cc1: warnings being treated as errors
y.c: In function âmainâ:
./y.h:11: error: array subscript is above array bounds
[hjl@gnu-6 tmp]$


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36902