On Mon, Feb 4, 2019 at 3:19 AM Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Sun, Feb 03, 2019 at 08:07:22AM -0800, H.J. Lu wrote:
> > + /* If the misalignment of __P > 8, subtract __P by 8 bytes.
> > + Otherwise, subtract __P by the misalignment. */
> > + if (offset > 8)
> > + offset = 8;
> > + __P = (char *) (((__SIZE_TYPE__) __P) - offset);
> > +
> > + /* Zero-extend __A and __N to 128 bits and shift right by the
> > + adjustment. */
> > + unsigned __int128 __a128 = ((__v1di) __A)[0];
> > + unsigned __int128 __n128 = ((__v1di) __N)[0];
> > + __a128 <<= offset * 8;
> > + __n128 <<= offset * 8;
> > + __A128 = __extension__ (__v2di) { __a128, __a128 >> 64 };
> > + __N128 = __extension__ (__v2di) { __n128, __n128 >> 64 };
>
> We have _mm_slli_si128/__builtin_ia32_pslldqi128, why can't you use that
> instead of doing the arithmetics in unsigned __int128 scalars?
>
Since "PSLLDQ xmm1, imm8" takes an immediate operand, __int128
doesn't need a switch statement.
--
H.J.
