From: "\"Martin v. Löwis\"" <martin@v.loewis.de>
To: John David Anglin <dave@hiauly1.hia.nrc.ca>
Cc: jakub@redhat.com, aj@suse.de, gcc@gcc.gnu.org,
libc-alpha@sources.redhat.com
Subject: Re: Miscompilation of glibc with CVS mainline
Date: Thu, 02 Jan 2003 17:48:00 -0000 [thread overview]
Message-ID: <3E147AFA.3000600@v.loewis.de> (raw)
In-Reply-To: <200301021738.h02HcP43010808@hiauly1.hia.nrc.ca>
John David Anglin wrote:
>>As GCC is not told in any way that weak_func is actually weak, I think
>>it is glibc's fault.
>
>
> This is definitely a gcc problem. This is the code arising from
> Andreas' testcase for hppa-linux at -O2:
[...]
> We have completely lost the `if'. As a result, weak_func is always
> called.
It's not a gcc bug. weak_func is a function, so &weak_func is always
unequal to null - that is guaranteed by the C programming language.
That's why the compiler is entitled to eliminate the test, under the
as-if rule. If you want to declare a function whose address can be zero,
you need to declare it weak, using the relevant extension in GNU C.
Regards,
Martin
next prev parent reply other threads:[~2003-01-02 17:48 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-01-01 17:43 John David Anglin
2003-01-02 13:18 ` Andreas Jaeger
2003-01-02 13:27 ` Jakub Jelinek
2003-01-02 13:53 ` Andreas Jaeger
2003-01-02 14:41 ` Andreas Jaeger
2003-01-02 21:10 ` Andreas Jaeger
2003-01-02 17:38 ` John David Anglin
2003-01-02 17:48 ` "Martin v. Löwis" [this message]
2003-01-02 18:52 ` John David Anglin
2003-01-02 18:58 ` Paul Jarc
2003-01-02 19:10 ` Dale Johannesen
2003-01-02 19:16 ` John David Anglin
2003-01-02 19:26 ` Paul Jarc
2003-01-02 20:25 ` Martin v. Löwis
2003-01-02 22:11 ` Richard Henderson
2003-01-03 1:02 ` John David Anglin
2003-01-03 1:35 ` Richard Henderson
2003-01-02 19:42 ` Ulrich Drepper
2003-01-02 22:16 ` Richard Henderson
2003-01-03 0:14 ` Fergus Henderson
-- strict thread matches above, loose matches on Subject: below --
2003-01-04 18:54 Robert Dewar
2003-01-04 17:52 Robert Dewar
[not found] <no.id>
2003-01-02 17:48 ` John David Anglin
2003-01-02 17:54 ` Jakub Jelinek
2003-01-02 18:58 ` John David Anglin
2003-01-02 17:57 ` Daniel Jacobowitz
2003-01-01 13:37 Andreas Jaeger
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