From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24371 invoked by alias); 17 May 2002 05:06:02 -0000 Mailing-List: contact gcc-prs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-prs-owner@gcc.gnu.org Received: (qmail 24343 invoked by uid 71); 17 May 2002 05:06:01 -0000 Date: Thu, 16 May 2002 22:06:00 -0000 Message-ID: <20020517050601.24339.qmail@sources.redhat.com> To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, From: Richard Henderson Subject: Re: optimization/6673: gcc-3.1 produces wrong assembly code Reply-To: Richard Henderson X-SW-Source: 2002-05/txt/msg00478.txt.bz2 List-Id: The following reply was made to PR optimization/6673; it has been noted by GNATS. From: Richard Henderson To: Nam SungHyun , rth@gcc.gnu.org, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, namsh@kldp.org, nobody@gcc.gnu.org, gcc-gnats@gcc.gnu.org Cc: Subject: Re: optimization/6673: gcc-3.1 produces wrong assembly code Date: Thu, 16 May 2002 22:02:00 -0700 On Fri, May 17, 2002 at 01:53:24PM +0900, Nam SungHyun wrote: > I saw the feed back message from the gnats web, but did not get a > mail. Did not know how I can reply for that feedback. The gnats bug form has an originator email address that it cc's all status changes on. Did you mistype it? > the 'a' in my example source is a 'global variable'. > So, should the gcc treat it as a volatile by default? No. > There are so many multi-threaded program. I didn't see > any program which use volatile for the global variable. Nor does any C compiler produce "thread aware" code by default. You have to use cpu-specific thread synchronization primitives in order for that to work reliably. Such a primitive would as a side effect tell the compiler that data must be committed to memory, which would cause 'a' to be written. You did none of these. r~