[Bug c++/57274] New: [4.8/4.9 Regression] Bogus sequence-point warning in C++

[ppluzhnikov at google dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57274

            Bug ID: 57274
           Summary: [4.8/4.9 Regression] Bogus sequence-point warning in
                    C++
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ppluzhnikov at google dot com

Test case:


#include <unistd.h>

void fn (int *data) {
  write (1, data++, sizeof (*data));
}


Using trunk GCC:

gcc -c -Wall t.c && echo ok
ok

g++ -c -Wall t.c
t.c: In function ‘void fn(int*)’:
t.c:4:36: warning: operation on ‘data’ may be undefined [-Wsequence-point]
   write (1, data++, sizeof (*data));
                                    ^


sizeof(*data)  does *not* dereference data.