From: Peter Stephenson <p.stephenson@samsung.com>
To: <zsh-workers@zsh.org>
Subject: Re: -Wrestrict warning on cc 8.3.0
Date: Wed, 10 Apr 2019 09:48:02 +0100 [thread overview]
Message-ID: <1554886082.6252.3.camel@samsung.com> (raw)
In-Reply-To: <1554373291.5874.3.camel@samsung.com>
On Thu, 2019-04-04 at 11:21 +0100, Peter Stephenson wrote:
> On Wed, 2019-04-03 at 20:59 +0200, Wesley Schwengle wrote:
> >
> > During a make of the latest master I got the following warning:
> >
> > gcc -c -I. -I../../Src -I../../Src -I../../Src/Zle -I. -DHAVE_CONFIG_H
> > -DMODULE -Wall -Wmissing-prototypes -O2 -fPIC -o compctl..o compctl.c
> > compctl.c: In function ‘makecomplistflags.isra.6’:
> > compctl.c:3340:7: warning: ‘strcpy’ accessing 1 byte at offsets [0,
> > 9223372036854775807] and [0,9223372036854775807] may overlap 1 byte at
> > offset 0 [-Wrestrict]
> > strcpy(p, p + bl);
> > ^~~~~~~~~~~~~~~~~
> > rm -f compctl.so
> This warning is thoroughly opaque --- and not occurring with a locally
> compiled gcc 8.3.0 on my Ubuntu 16.04 64-bit Intel system --- but the
> code isn't exactly crystal clear, either (subtracting a number off then
> adding it immediately back on again isn't generally regarded as great
> style), and it's quite possible the copy is overlapping. Also, the last
> person to worry about code optimisation in compctl emigrated to the
> Undying Lands a decade ago (maybe I can still find the postcard...)
>
> Can somebody verify the following is equivalent apart from dealing with
> a possible overlapping copy? I've no way of ensuring this code gets
> exercised.
I've applied this anyway.
pws
next prev parent reply other threads:[~2019-04-10 8:48 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20190403190049epcas3p4c02406857f7f26510ea8969c969a655e@epcas3p4.samsung.com>
2019-04-03 18:59 ` Wesley Schwengle
2019-04-04 10:21 ` Peter Stephenson
2019-04-10 8:48 ` Peter Stephenson [this message]
2019-04-10 8:58 ` Roman Perepelitsa
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