Hi Daniel,
> On 09/19/2017 01:58 AM, Jakub Jelinek wrote:
>> What can be done in libgcc is detect in configure whether the assembler
>> supports AVX, and if not, provide some alternative (e.g. because the insns
>> are always the same, you could just code them as .byte or something similar).
>>
>> Say like:
>> --- i386-asm.h 2017-09-18 18:34:30.917126996 +0200
>> +++ i386-asm.h 2017-09-19 08:56:58.829559038 +0200
>> @@ -70,6 +70,7 @@ ASMNAME(fn):
>> #ifdef MS2SYSV_STUB_AVX
>> # define MS2SYSV_STUB_PREFIX __avx_
>> # define MOVAPS vmovaps
>> +# define BYTE .byte
>> #elif defined(MS2SYSV_STUB_SSE)
>> # define MS2SYSV_STUB_PREFIX __sse_
>> # define MOVAPS movaps
>> @@ -84,7 +85,8 @@ ASMNAME(fn):
>> FUNC_END(PASTE2(MS2SYSV_STUB_PREFIX, base_name))
>>
>> /* Save SSE registers 6-15. off is the offset of rax to get to xmm6. */
>> -# define SSE_SAVE \
>> +# ifdef HAVE_AS_AVX
>
> I'm not exactly an autotools expert, but libtim defines HAVE_AS_AVX from
> libitm/acinclude.m4 -- of course I need it in libgcc. Similarly, gcc
> has a nice generic gcc_GAS_CHECK_FEATURE macro in gcc/acinclude.m4 which
> it uses for all of its HAVE_AS_* macro tests defined in
> gcc/configure.ac. I can just copy, paste and edit what's in libitm, but
> I find that rather distasteful. Is there a cleaner way to do this? Can
> I suck gcc_GAS_CHECK_FEATURE and it's deps out of gcc/acinclude.m4 and
> put it somewhere central, like config/as.m4? The upside would be the
> ability to make HAVE_AS_* macros in other sub-projects more uniform.
This might be an option as a followup: less code duplication is
certainly a good thing ;-)
> Alternatively, I can just do the copy and paste and deal with it -- it's
> not that much code. :)
However, given that the above will take some time and testing and your
patch has broken macOS bootstrap, I'd go this route now to unbreak the
tree ASAP.
Rainer
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Rainer Orth, Center for Biotechnology, Bielefeld University
