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From: "prasoonsaurav.nit at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/51834] -Wsequence-point fails when convoluted expressions with multiple side effects are used
Date: Thu, 12 Jan 2012 09:08:00 -0000	[thread overview]
Message-ID: <bug-51834-4-zuhLnV98kU@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-51834-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51834

--- Comment #2 from Prasoon <prasoonsaurav.nit at gmail dot com> 2012-01-12 09:07:52 UTC ---
@Richard Guenther 

Considering the expression i += (i,i++,i) +i;

(i,i++,i) involves change in the value of i, however comma introduces a
sequence point so very roughly considering it equivalent to
func(_some_side_effect_on_i)

we have i += func(_some_side_effect_on_i) + i;

Do you still think the behavior is well defined?

Another C++ example would be ++a = 10; where 'a'is of type int.
This invokes UB but there is no warning from the compiler side even after we
use this flag. Raising a similar bug for C++ because the differ may be
different in C and C++.

Thanks
Prasoon


  parent reply	other threads:[~2012-01-12  9:08 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-12  6:29 [Bug c/51834] New: " prasoonsaurav.nit at gmail dot com
2012-01-12  8:51 ` [Bug c/51834] " rguenth at gcc dot gnu.org
2012-01-12  9:08 ` prasoonsaurav.nit at gmail dot com [this message]
2012-01-12  9:20 ` schwab@linux-m68k.org
2012-04-19 15:07 ` vincent-gcc at vinc17 dot net

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