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Date: Mon, 29 Nov 2010 11:57:00 -0000
From: Nicholas Mc Guire <der.herr@hofr.at>
To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>,	Am?rico Wang <xiyou.wangcong@gmail.com>,	Hui Zhu <teawater@gmail.com>, linux-kernel@vger.kernel.org,	gdb@sourceware.org, hellogcc@freelists.org,	linux-kbuild@vger.kernel.org
Subject: Re: [PATCH] Built kernel without -O2 option
Message-ID: <20101129115724.GA32318@opentech.at>
References: <AANLkTimewZ4QhxzL2vOYYV85pegy8Fu6Rb4XUAPqGUXS@mail.gmail.com> <20101129081619.GD5218@cr0.nay.redhat.com> <4CF37603.5080301@de.ibm.com> <52488.94.211.195.167.1291029121.squirrel@gate.crashing.org> <4CF38BBA.4020202@de.ibm.com>
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On Mon, 29 Nov 2010, Christian Borntraeger wrote:

> Am 29.11.2010 12:12, schrieb Segher Boessenkool:
> >> In essence -O2 just tells gcc to activate a list of optimizations
> >> gcc  -Q -O2 --help=optimizers

I think for completness you would need to pass

 gcc -Wextra -Q -O2 --help=optimizers

or you could miss some options

> >> tells you what.
> > 
> > Not quite; see http://gcc.gnu.org/wiki/FAQ#optimization-options .
> > 
> 
> Erm...right. Thank you.

well I guess you always could explicidly turn off all optioins with 
-fnoWHATEVER you want to disable and thus remove all unwanted flags 
- admitedly a bit painfull though.

hofrat