[Patch] x86: Enable support for Intel UINTR extension

[Uros Bizjak]

> > Please also add -muintr to g++.dg/other/i386-{2,3}.C and
> > >> > > gcc.target/i386-sse-{12,13,14,22,23}.c. This will test new intrinsics
> > >> > > header.
> > >> > >
> > >> >
> > >> > Thanks for your review. We found that without adding -muintr, the intrinsics header could also be tested. Make-check for these file all get passed.
> > >> >
> > >> > And there is no intrinsic/builtin with const int parameter. So we remove -muintr from these files.
> > >>
> > >> Can your double check that relevant instructions are indeed generated?
> > >> Without -muintr, relevant patterns in i386.md are effectively blocked,
> > >> and perhaps a call to __builtin_ia32_* is generated instead.
> > >
> > >
> > > Yes, in sse-14.s we have
> > >
> > > _clui:
> > > .LFB136:
> > >         .cfi_startproc
> > >         pushq   %rbp
> > >         .cfi_def_cfa_offset 16
> > >         .cfi_offset 6, -16
> > >         movq    %rsp, %rbp
> > >         .cfi_def_cfa_register 6
> > >         clui
> > >         nop
> > >         popq    %rbp
> > >         .cfi_def_cfa 7, 8
> > >         ret
> > >         .cfi_endproc
> >
> > Strange, without -muintr, it should not be generated, and some error
> > about failed inlining due to target specific option mismatch shoul be
> > emitted.
> >
> > Can you please investigate this a bit more?
> >
>
> Because of function target attribute?

I don't think so. Please consider this similar testcase:

--cut here--
#ifndef __SSE2__
#pragma GCC push_options
#pragma GCC target("sse2")
#define __DISABLE_SSE2__
#endif /* __SSE2__ */

typedef double __v2df __attribute__ ((__vector_size__ (16)));
typedef double __m128d __attribute__ ((__vector_size__ (16), __may_alias__));

extern __inline __m128d __attribute__((__gnu_inline__,
__always_inline__, __artificial__))
_mm_add_sd (__m128d __A, __m128d __B)
{
  return (__m128d)__builtin_ia32_addsd ((__v2df)__A, (__v2df)__B);
}

#ifdef __DISABLE_SSE2__
#undef __DISABLE_SSE2__
#pragma GCC pop_options
#endif /* __DISABLE_SSE2__ */


__v2df foo (__v2df a, __v2df b)
{
  return _mm_add_sd (a, b);
}
--cut here--

$ gcc -O2 -mno-sse2 -S -dp sse2.c
sse2.c: In function ‘foo’:
sse2.c:11:1: error: inlining failed in call to ‘always_inline’
‘_mm_add_sd’: target specific option mismatch
  11 | _mm_add_sd (__m128d __A, __m128d __B)
     | ^~~~~~~~~~
sse2.c:24:10: note: called from here
  24 |   return _mm_add_sd (a, b);
     |          ^~~~~~~~~~~~~~~~~

I'd expect some similar warning from missing -mumip.

Uros.