[Bug c/49620] New: piece of code from modification to dvblast but cant get it to compile and run correctly

["joolzg at btinternet dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49620

           Summary: piece of code from modification to dvblast but cant
                    get it to compile and run correctly
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: joolzg@btinternet.com


Created attachment 24664
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24664
bug report

I have a function that only works when i add another function call inbetween.

block_t *file_Read( mtime_t i_poll_timeout )
{
    i_wallclock = mdate();

    {
        block_t *p_ts, **pp_current = &p_ts;
        int i, i_len;

        if ( !i_last_packet )
        {
            switch (i_print_type) {
            case PRINT_XML:
                printf("<STATUS type=\"lock\" status=\"1\"/>\n");
                break;
            default:
                printf("frontend has acquired lock\n" );
            }
        }
        i_last_packet = i_wallclock;

        i_len = 0;
        for ( i = 0; i < i_bufsize / TS_SIZE; i++ )
        {
            *pp_current = block_New();
            i_len2 = fread( (*pp_current)->p_ts, 1, TS_SIZE, file_input);
//            msg_Warn( NULL, "read from file %s (%s) %d %p",
//                       filename, strerror(errno), i_len2, pp_current );
            if ( i_len2 < 188 )
            {
            if ( i_len2 < 188 )
            {
                msg_Err( NULL, "couldn't read from file %s (%s) %d %p",
                         filename, strerror(errno), i_len2, pp_current );
                i_len = 0;
                break;
            }
            i_len++;
            pp_current = &(*pp_current)->p_next;
        }

        pp_current = &p_ts;
        while ( i_len && *pp_current )
        {
            pp_current = &(*pp_current)->p_next;
            i_len--;
        }

        if ( *pp_current )
            msg_Dbg( NULL, "partial buffer received" );

        block_DeleteChain( *pp_current );
        *pp_current = NULL;

        return p_ts;
    }

    return NULL;
}

Now the code above DOES not work in 
gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu4)
or
gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)

Both machines are Ubuntu 64bit.

If the commented out msg_Warn is uncommented then the code works and we get no
error message

Ive also run it through clang and came up with no errors

joolz