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From: "mikpe at it dot uu dot se" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/39736] signed overflow in loop induction variable: missing warning and wrong code
Date: Sun, 12 Apr 2009 09:11:00 -0000	[thread overview]
Message-ID: <20090412091114.7443.qmail@sourceware.org> (raw)
In-Reply-To: <bug-39736-15165@http.gcc.gnu.org/bugzilla/>



------- Comment #2 from mikpe at it dot uu dot se  2009-04-12 09:11 -------
(In reply to comment #1)
> There is no undefined behavior here (increment of a short value converts 
> to int, increments then converts back to short, none of which are 
> undefined), so at least the wrong code issue would be the same as bug 
> 35634.

It's not undefined, but the conversion from int back to short provokes
implementation-defined behaviour when the int value doesn't fit in a short.
That makes this test program not strictly conforming.

The lack of a compile-time warning is unfortunate, but I don't think this is a
case of wrong-code.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39736


  parent reply	other threads:[~2009-04-12  9:11 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-11 12:30 [Bug tree-optimization/39736] New: " edwintorok at gmail dot com
2009-04-11 12:52 ` [Bug tree-optimization/39736] " joseph at codesourcery dot com
2009-04-12  9:11 ` mikpe at it dot uu dot se [this message]
2009-04-12  9:32 ` edwintorok at gmail dot com
2009-04-12 21:34 ` mikpe at it dot uu dot se
2009-04-13  6:56 ` edwintorok at gmail dot com
2009-04-13  7:53 ` schwab at linux-m68k dot org
2009-04-13  8:20 ` rguenth at gcc dot gnu dot org

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