F22 System Wide Change: Harden all packages with position-independent code

[Reindl Harald]

Am 19.01.2015 um 21:34 schrieb drago01:
> On Mon, Jan 19, 2015 at 3:42 PM, Reindl Harald <h.reindl at thelounge.net> wrote:
>>
>> Am 19.01.2015 um 15:28 schrieb Gerd Hoffmann:
>>>>>
>>>>> Would that make it impossible to run fedora on sse-only i686 CPUs?
>>>>
>>>>
>>>> Yes, but test coverage for those CPUs is already rather poor, so I don't
>>>> expect them to work anymore.
>>>
>>>
>>> See other replies, people are running such machines.
>>>
>>> Given x86_64 exists for many years and even embedded (see aarch64) is
>>> moving to 64bit these days i386 clearly is for old legacy hardware.  If
>>> you need performance you don't run a i386 machine.
>>>
>>> So, why bother raising the bar for i386 by requiring more cpu features?
>>> It doesn't help anyone.
>>
>>
>> "rpmrc" has optflags: for different architectures
>>
>> so why not optimize only "optflags: x86_64" for more recent hardware?
>> since i686 is a complete different build anyways it won't matter
>>
>> on my private builders it's "-mmmx -msse2 -msse3 -msse4.1 -msse4.2 -maes
>> -mfpmath=sse"
>
> Because that doesn't make sense for multiple reasons:

you show none below because it said "keep i686 flags unchanged"

> 1) mmx is basically obsolete

in theory

> 2) sse2 is the default fp ABI on x86_64 anyway and thus supported by
> *all* x86_64 cpus

so be it

> 3) Requiring sse4.2 or even 4.1 would exclude a lot of hardware

did i propose that?

i said "private builders" to show that keep supporting > 10 years old 
hardware is just silly because you waste HW capabilities - noweher did i 
propose *that* falgs

> 4) You don't just throw in some compiler flags and assume it will gain
> you anything (you'd probably have to either turn on O3 or
> vectorization as well)

-O3 is the default for my builds starting with 2006

> .. most applications where it really matters do
> detection at runtime (even glibc does that)

the topic is still: hwta can be changed in the x86_64 flags *without* 
break old 32bit crap some people rely for several reasons



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