On Mon, May 20, 2019 at 2:52 PM Uros Bizjak <ubiz...@gmail.com> wrote:
>
> On Mon, May 20, 2019 at 11:39 PM Jeff Law <l...@redhat.com> wrote:
> >
> > On 5/20/19 3:36 PM, H.J. Lu wrote:
> > > With SSE emulation of MMX intrinsics in 64-bit mode,
> > >
> > > ---
> > > __v8qi test ()
> > > {
> > > __v8qi mm0 = {1,2,3,4,5,6,7,8};
> > > __v8qi mm1 = {11,22,33,44,55,66,77,88};
> > > volatile __m64 x;
> > >
> > > x = _mm_add_pi8 (mm0, mm1);
> > >
> > > return x;
> > > }
> > > ---
> > >
> > > is compiled into
> > >
> > > movq .LC0(%rip), %xmm0
> > > movq .LC1(%rip), %xmm1
> > > paddb %xmm1, %xmm0
> > > movq %xmm0, -8(%rsp)
> > > movq -8(%rsp), %xmm0
> > > ret
> > >
> > > instead of
> > >
> > > movq .LC1(%rip), %mm0
> > > paddb .LC0(%rip), %mm0
> > > movq %mm0, -8(%rsp)
> > > movq -8(%rsp), %xmm0
> > > ret
> > >
> > > Adjust gcc.target/i386/pr22076.c for 64-bit.
> > >
> > > * gcc.target/i386/pr22076.c: Adjusted for 64-bit.
> > Well, it looks like you're just papering over a code quality regression?
> > Or am I missing something?
>
> We have to load 64bit value from memory to 128 bit XMM register using movq.
>
> OTOH, we could just use -mno-sse2 which disables XMM emulation.
>
Works for me.
--
H.J.
