Re: [RFC] [PATCH] Introduce configure flag --with-stage1-cflags.

[Martin Liška <mliska at suse dot cz>]

PING^1

Richi are you fine with the suggested change? I basically followed your advises :)

Martin

On 05/26/2017 03:00 PM, Martin Liška wrote:
> On 05/26/2017 01:55 PM, Richard Biener wrote:
>> On Fri, May 26, 2017 at 1:51 PM, Jakub Jelinek <jakub@redhat.com> wrote:
>>> On Fri, May 26, 2017 at 01:46:47PM +0200, Richard Biener wrote:
>>>> On Thu, May 25, 2017 at 11:23 AM, Martin Liška <mliska@suse.cz> wrote:
>>>>> Hello.
>>>>>
>>>>> After a discussion with Richi, using adding "-O2" to STAGE1 cflags with a recent
>>>>> enough compiler can significantly speed up bootstrap. Thus I'm suggesting to
>>>>> introduce --with-stage1-cflags where one can provide such options.
>>>>
>>>> I don't think this is necessary -- you can always override with STAGE1_CFLAGS.
>>>>
>>>>> Apart from that, maybe it would be handy to automatically enable "-O2" when
>>>>> one has a recent compiler? Do we have an example where we detect host compiler
>>>>> and it's version?
>>>>
>>>> Don't know about version but configury already detects that we use GCC, so that
>>>> knowledge should be readily available.
>>>
>>> Well, it certainly shouldn't be -O2 by default for any system GCC, more
>>> something like if it is major of the configured configure minus 1 or newer
>>> (or minus 2?), then use -O2, otherwise default to -O0 as before.
>>
>> I'd still default to -O0 on release branches regardless of version and then
>> for development we can probably simply use "any GCC" when people have
>> the chance to override.
> 
> Ok, sending new patch that does that on experimental branches for ${CC} --version
> being a GCC newer than 4.9.
> 
> Martin
> 
>>
>> At least for me host GCC 4.8 works quite well with -O2.
>>
>> Richard.
>>
>>>         Jakub
>