[Bug c/12552] New: Problem with increment operator gcc/g++

[Bug c/12552] New: Problem with increment operator gcc/g++

[devnull at frogshit dot com]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12552

           Summary: Problem with increment operator gcc/g++
           Product: gcc
           Version: 3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: devnull at frogshit dot com
                CC: gcc-bugs at gcc dot gnu dot org

% more price.c
#include <stdio.h>

int main()
{
  int price = 10;

  int cost = price++ + ++price;
  printf("%d\n", cost);
  return 0;
}

% gcc price.c
% ./a.out
21
% gcc -O price.c
% ./a.out
22

I reported this error once before, back in the 2.95 days, I think.

[Bug c/12552] Problem with increment operator gcc/g++

[falk at debian dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12552


falk at debian dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


------- Additional Comments From falk at debian dot org  2003-10-09 16:30 -------
price is modified more than once without an intervening sequence point, so the
code is invalid.

[Bug c/12552] Problem with increment operator gcc/g++

[devnull at frogshit dot com]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12552



------- Additional Comments From devnull at frogshit dot com  2003-10-09 16:33 -------
The answer should be 22.  When I compile using gcc/g++, the
answer is 21.  When I compile using gcc/g++ -O, the answer
is correct.  I reported this bug once before.

Thanks!!

Mark

[Bug c/12552] Problem with increment operator gcc/g++

[devnull at frogshit dot com]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12552


devnull at frogshit dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |


------- Additional Comments From devnull at frogshit dot com  2003-10-09 16:40 -------
I don't know what invalid code means.  The code is syntactically
correct, but one gets different semantics depending on whether
the compiler does or does not optimize.  It seems reasonable
to expect the same output regardless of the level of optimization.

[Bug c/12552] Problem with increment operator gcc/g++

[falk at debian dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12552


falk at debian dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


------- Additional Comments From falk at debian dot org  2003-10-09 16:43 -------
The code has undefined behavior, which means that printing 21,
printing 22, printing 42, crashing, refusing to compile, and
formatting your hard disk would all be correct results. Please read
the documentation on -Wsequence-point and a good C book.

[Bug c/12552] Problem with increment operator gcc/g++

[schwab at suse dot de]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12552


schwab at suse dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |s0094247 at sms dot ed dot
                   |                            |ac dot uk


------- Additional Comments From schwab at suse dot de  2003-10-10 15:20 -------
*** Bug 12569 has been marked as a duplicate of this bug. ***

[Bug c/12552] Problem with increment operator gcc/g++

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-08-05 14:57 -------
Reopen these bugs... 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12552

[Bug c/12552] Problem with increment operator gcc/g++

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2004-08-05 15:02 -------
...mark as duplicate of PR 11751. 

*** This bug has been marked as a duplicate of 11751 ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12552