From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ricardo Wurmus <rekado@elephly.net>
Subject: Re: [PATCH 2/2] gnu: zita-convolver: Drop the '-march=native'
	optimization.
Date: Thu, 07 Jan 2016 09:37:31 +0100
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宋文武 <iyzsong@member.fsf.org> writes:

> Ricardo Wurmus <rekado@elephly.net> writes:
>
>>> +              (snippet
>>> +               ;; Don't optimize for a specific processor architecture.
>>> +               '(substitute* "libs/Makefile"
>>> +                  (("^CXXFLAGS \\+= -march=native") "")))
>>> +              (modules '((guix build utils)))
>>
>> Is this to avoid that packages are optimised for the CPU of the build
>> slave?
> Yes, using that from hydra will crash guitarix for me.
> Same as: <https://bugs.archlinux.org/task/36248>.

Guitarix also crashes for me on i686 — and I thought it was something to
do with my machine or the broken build of eigen.

>> If so, could we instead pass different optimisation flags for
>> different architectures?  For a convolver I’d prefer to have *some*
>> optimisation, even if it’s just the greatest common divisor.
> I don't familiar with optimization flags, but according to:
>   <https://wiki.gentoo.org/wiki/GCC_optimization#Optimizing>
> I think '-march=native' should be dropped definitely, it enable all
> the CPU specified instruction set when building on the slave.
> And it's not clear to me what *some* flags are, suppose we don't want
> any CPU specified (-msse3, -msse4, etc.) thing.

Okay.  I think removing “-march=native” is worth doing anyway, so let’s
ignore adding optimisation flags for now.

Thank you!