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From: "su at cs dot ucdavis.edu" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug lto/61741] wrong code by LTO on x86_64-linux-gnu
Date: Tue, 08 Jul 2014 05:36:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61741

--- Comment #2 from Zhendong Su <su at cs dot ucdavis.edu> ---
(In reply to Andi Kleen from comment #1)
>  char c = 0;
>   for (; a; a--)
>     for (; c >= 0; c++);
> 
> Don't you rely on signed overflow which is undefined?

No, there is no signed overflow since the variable c is a char so the
increments are performed on int first and then cast back to char: (char) ((int)
c + 1).   

The same also holds for short.