[patch i386]:Ensure intrinsic functions are declared "C"

[Kai Tietz]

2010/5/12 Richard Guenther <richard.guenther@gmail.com>:
> On Wed, May 12, 2010 at 3:43 PM, Kai Tietz <Kai.Tietz@onevision.com> wrote:
>> "H.J. Lu" <hjl.tools@gmail.com> wrote on 12.05.2010 15:31:07:
>>
>>> On Wed, May 12, 2010 at 3:23 AM, Kai Tietz <Kai.Tietz@onevision.com>
>> wrote:
>>> > Hello,
>>> >
>>> > At the moment intrinsic functions for headers don't have a explicit
>>> > language binding. As types, structures, and functions are quite
>> different
>>> > handled in c++ and c, this cause at least for x86/x64 windows to
>> issues,
>>> > as for this platforms the intrinsic functions have "C" language scope
>> by
>>> > definition.
>>> > I tested for x86_64-pc-linux-gnu, i686-pc-mingw32, x86_64-w64-mingw32,
>> and
>>> > i686-pc-cygwin. And I didn't found any regressions.
>>> >
>>> > 2010-05-12  Kai Tietz
>>> >
>>> >        * config/i386/abmintrin.h: Add extern "C" guard for c++.
>>> >        * config/i386/ammintrin.h: Likewise.
>>> >        * config/i386/avxintrin.h: Likewise.
>>> >        * config/i386/cpuid.h: Likewise.
>>> >        * config/i386/emmintrin.h: Likewise.
>>> >        * config/i386/fma4intrin.h: Likewise.
>>> >        * config/i386/gmm_malloc.h: Likewise.
>>> >        * config/i386/ia32intrin.h: Likewise.
>>> >        * config/i386/lwpintrin.h: Likewise.
>>> >        * config/i386/mm3dnow.h: Likewise.
>>> >        * config/i386/mmintrin.h: Likewise.
>>> >        * config/i386/pmm_malloc.h: Likewise.
>>> >        * config/i386/pmmintrin.h: Likewise.
>>> >        * config/i386/popcntintrin.h: Likewise.
>>> >        * config/i386/smmintrin.h: Likewise.
>>> >        * config/i386/tmmintrin.h: Likewise.
>>> >        * config/i386/wmmintrin.h: Likewise.
>>> >        * config/i386/xmmintrin.h: Likewise.
>>> >        * config/i386/xopintrin.h: Likewise.
>>> >
>>> > Ok for apply to trunk?
>>> >
>>>
>>> Those function are always inlined. What do we need extern "C"?
>>>
>>>
>>>
>>> --
>>> H.J.
>>>
>>
>> As I described above. C++ and C have different name mangling and for win32
>> intrinsic have C scope. And as far as I can see it doesn't hurt, so the
>> question is here more why we should stick here not unifying the language
>> scope?
>
> They won't have external linkage so why would we care?
>
> Richard.
>
>> Regards,
>> Kai
>>
>> |  (\_/)  This is Bunny. Copy and paste Bunny
>> | (='.'=) into your signature to help him gain
>> | (")_(") world domination.
>>
>>
>

The issue, which occures here is, that a user wants - for example - to
include <xmmintrin.h> header in C++. Now he includes afterwards for
windows the math.h/intrin.h (which both have explicit C language
scope). What happens here? A bunch of warnings/failures caused by C++
vs. C language scope.
So why we shouldn't care?

Regards,
Kai

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