2006-03-02 19:35:40

by Martin Bligh

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Subject: x86_64 compile spewing hundreds of warnings - started 2.6.15-git8

between 2.6.15-git7 and 2.6.15-git8 we started getting hundreds of
compile warnings:

-git7: http://test.kernel.org/20295/debug/test.log.0
-git8: http://test.kernel.org/20402/debug/test.log.0

Warnings look like this:

include/asm/bitops.h: In function `load_elf32_binary':
include/asm/bitops.h:30: warning: read-write constraint does not allow a
register
include/asm/bitops.h:30: warning: read-write constraint does not allow a
register
include/asm/bitops.h:65: warning: read-write constraint does not allow a
register
include/asm/bitops.h:65: warning: read-write constraint does not allow a
register
include/asm/bitops.h:30: warning: read-write constraint does not allow a
register
include/asm/bitops.h:30: warning: read-write constraint does not allow a
register
include/asm/bitops.h:65: warning: read-write constraint does not allow a
register
include/asm/bitops.h:65: warning: read-write constraint does not allow a
register
include/asm/bitops.h:30: warning: read-write constraint does not allow a
register
include/asm/bitops.h:30: warning: read-write constraint does not allow a
register
include/asm/bitops.h:65: warning: read-write constraint does not allow a
register
include/asm/bitops.h:65: warning: read-write constraint does not allow a
register


What do these mean? And how do we get rid of it?

Presumably caused by this:

http://www.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=636dd2b7def5c9c72551b51d4d516a65c269de08

or this:

http://www.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=92934bcbf96bc9dc931c40ca5f1a57685b7b813b


2006-03-02 19:50:07

by Andi Kleen

[permalink] [raw]
Subject: Re: x86_64 compile spewing hundreds of warnings - started 2.6.15-git8

On Thursday 02 March 2006 20:35, Martin Bligh wrote:

> include/asm/bitops.h:65: warning: read-write constraint does not allow a
> register
>
>
> What do these mean?

They mean you have a buggy compiler.


> And how do we get rid of it?
>
> Presumably caused by this:
>
> http://www.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=636dd2b7def5c9c72551b51d4d516a65c269de08
>
> or this:
>
> http://www.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=92934bcbf96bc9dc931c40ca5f1a57685b7b813b

It was the bitops.h constrain change.

The problem is that reverting them would be readding the problem. Maybe we need to
#ifdef it.

-Andi