Hello Ian, Uroš,
On 30 May 09:19, Uros Bizjak wrote:
> Hello!
>
> > This error is because _mm_pause is defined in the scope of #pragma GCC
> > target("sse"). But _mm_pause, which simply generates the pause
> > instruction, does not require SSE support. The pause instruction has
> > nothing really to do with SSE, and it works on all x86 processors (on
> > processors that do not explicitly recognize it, it is a nop).
> >
> > I propose the following patch, which moves _mm_pause out of the pragma
> > target scope.
> >
> > I know that x86intrin.h provides a similar intrinsic, __pause, but I
> > think it's worth making _mm_pause work reasonably as well.
> >
> > I'm running a full testsuite run. OK for mainline if it passes?
> >
> > gcc/ChangeLog:
> >
> > 2014-05-29 Ian Lance Taylor <i...@google.com>
> >
> > * config/i386/xmmintrin.h (_mm_pause): Move out of scope of pragma
> > target("sse").
> >
> > gcc/testsuite/ChangeLog:
> >
> > 2014-05-29 Ian Lance Taylor <i...@google.com>
> >
> > * gcc.target/i386/pause-2.c: New test.
>
> The patch looks OK to me, but please wait a day or two for possible
> comments (compatibility, etc) from Kirill.
That is definetely a bug and I see no compatibility issues in the fix.
The only nit I see: maybe it'd be better to put this cpuid-less intrinsic
into immintin.h? xmmintrin.h serves for SSE.
--
Thanks, K
