From: "Marp" <Marp AT 0 DOT 0 DOT 0 DOT 0>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Compiler optimization bug
Date: Sun, 12 Dec 1999 11:43:07 -0500
Organization: MindSpring Enterprises
Lines: 39
Message-ID: <830j66$is$1@nntp6.atl.mindspring.net>
References: <830aq2$68s$1 AT news-int DOT gatech DOT edu>
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Robert Ruehlmann <rr9 AT angband DOT org> wrote in message
news:830aq2$68s$1 AT news-int DOT gatech DOT edu...
> I think I've found a bug in the DJGPP compiler (gcc 2.95.2).  When
optimized
> with -O2 the following small sample program goes into an infinite loop.
> Debugging with gdb shows strange behaviour like modifications of the
'size'
> variable.
>
> <-- cut here -->
> static void bug(int size, int tries)

try changing this line to this instead:

static void bug(volatile int size, int tries)

> {
>     int i;
>     int num = 0;
>
>     while (num < size)
>     {
>         for (i = 1; i < tries; i++) num++;
>     }
> }
>
> int main()
> {
>     bug(5, 10);
>     return 0;
> }
> <-- cut here -->
>
> --
> Robert Ruehlmann ( rr9 AT angband DOT org )
> "Thangorodrim - The Angband Page" : http://thangorodrim.angband.org/
> Visit the #angband chat channel at Othernet (irc.othernet.org).