Windows breakage -- again

[Johan Tibell]

Alright, then which Make file do we need to fix to make sure GCC is
called correctly? Also, I remember reading that some time during the
4.x GCC series GCC switched to auto-detecting the arch to be that of
the machine being used. Could someone try to just switch GCC to a
newer version and see if it automatically stops trying to use i386,
leading to Simon's problem?

On Thu, Jul 17, 2014 at 8:37 AM, Niklas Larsson <metaniklas at gmail.com> wrote:
> It certainly shouldn't be built with i386, because that is generating code
> for a processor that lacks all these fancy atomic instructions. The first of
> them appears on the 486.
>
> i686 should be safe, it goes all the way back to Pentium Pro.
>
>
> 2014-07-17 8:33 GMT+02:00 Johan Tibell <johan.tibell at gmail.com>:
>
>> A perhaps silly question, *should* ghc-prim be built with i386 or i686?
>>
>> On Thu, Jul 17, 2014 at 8:33 AM, Niklas Larsson <metaniklas at gmail.com>
>> wrote:
>> > I just found exactly the same thing! Well, I used i686 instead.
>> >
>> > Sounds like it's worthwhile to see if this is limited to ghc-prim or if
>> > there's more stuff that's built with i386.
>> >
>> >
>> > 2014-07-17 8:21 GMT+02:00 Páli Gábor János <pali.gabor at gmail.com>:
>> >
>> >> 2014-07-17 0:51 GMT+02:00 Páli Gábor János <pali.gabor at gmail.com>:
>> >> > 2014-07-17 0:47 GMT+02:00 Niklas Larsson <metaniklas at gmail.com>:
>> >> >> I hope they can just be done away with at the source, that is to
>> >> >> make
>> >> >> gcc
>> >> >> generate the assembly primitives. GHC should already be built with
>> >> >> i686, but
>> >> >> does that reach ghc-prim?
>> >> >
>> >> > This depends on GCC -- if no -march=XXX is explicitly set, I guess it
>> >> > will take its default, which may vary platform by platform.
>> >>
>> >> All right, I have finally got a Windows (x64) machine and installed
>> >> the msys2 environment by the GHC wiki [1].  This has GCC 4.5.2 (as
>> >> Niklas wrote earlier), where the default -march is i386.  You should
>> >> see this line when trying to compile Johan's test program with the -v
>> >> flag set:
>> >>
>> >> COLLECT_GCC_OPTIONS= ... '-v' '-mtune=i386' '-march=i386'
>> >>
>> >> With the -march=i586 flag explicitly set in the command line, no
>> >> __sync_fetch_and_add_n() calls are generated.
>> >>
>> >> [1]
>> >>
>> >> https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Windows/MSYS2
>> >
>> >
>
>