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. Alternatively, I can just do the copy and paste and deal with it -- it's not that much code. :) Also, is there any sense in doing this same check for SSE support in the assembler? It's been out for 18 years now. Thanks, Daniel
