Re: [PATCH v1] x86: Use regular casting instead of _cvtmask64_u64 in strstr-avx512

[Noah Goldstein <goldstein.w.n@gmail.com>]

On Mon, Jul 11, 2022 at 3:18 PM Sunil Pandey <skpgkp2@gmail.com> wrote:
>
> On Mon, Jul 11, 2022 at 3:08 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > On Mon, Jul 11, 2022 at 3:07 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> > >
> > > _cvtmask64_u64 is not available before GCC7.
> > > ---
> > >  sysdeps/x86_64/multiarch/strstr-avx512.c | 12 +++++++-----
> > >  1 file changed, 7 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/sysdeps/x86_64/multiarch/strstr-avx512.c b/sysdeps/x86_64/multiarch/strstr-avx512.c
> > > index 2ab9e96db8..e41b44abe1 100644
> > > --- a/sysdeps/x86_64/multiarch/strstr-avx512.c
> > > +++ b/sysdeps/x86_64/multiarch/strstr-avx512.c
> > > @@ -26,6 +26,8 @@
> > >  #define ZMM_SIZE_IN_BYTES 64
> > >  #define PAGESIZE 4096
> > >
> > > +#define cvtmask64_u64(...) (uint64_t) (__VA_ARGS__)
> > > +
> > >  /*
> > >   Returns the index of the first edge within the needle, returns 0 if no edge
> > >   is found. Example: 'ab' is the first edge in 'aaaaaaaaaabaarddg'
> > > @@ -133,15 +135,15 @@ __strstr_avx512 (const char *haystack, const char *ned)
> > >    __m512i hay0 = _mm512_maskz_loadu_epi8 (loadmask, haystack + hay_index);
> > >    /* Search for NULL and compare only till null char */
> > >    uint64_t nullmask
> > > -      = _cvtmask64_u64 (_mm512_mask_testn_epi8_mask (loadmask, hay0, hay0));
> > > +      = cvtmask64_u64 (_mm512_mask_testn_epi8_mask (loadmask, hay0, hay0));
> > >    uint64_t cmpmask = nullmask ^ (nullmask - ONE_64BIT);
> > > -  cmpmask = cmpmask & _cvtmask64_u64 (loadmask);
> > > +  cmpmask = cmpmask & cvtmask64_u64 (loadmask);
> > >    /* Search for the 2 charaters of needle */
> > >    __mmask64 k0 = _mm512_cmpeq_epi8_mask (hay0, ned0);
> > >    __mmask64 k1 = _mm512_cmpeq_epi8_mask (hay0, ned1);
> > >    k1 = _kshiftri_mask64 (k1, 1);
> > >    /* k2 masks tell us if both chars from needle match */
> > > -  uint64_t k2 = _cvtmask64_u64 (_kand_mask64 (k0, k1)) & cmpmask;
> > > +  uint64_t k2 = cvtmask64_u64 (_kand_mask64 (k0, k1)) & cmpmask;
> > >    /* For every match, search for the entire needle for a full match */
> > >    while (k2)
> > >      {
> > > @@ -178,13 +180,13 @@ __strstr_avx512 (const char *haystack, const char *ned)
> > >        hay0 = _mm512_loadu_si512 (haystack + hay_index);
> > >        hay1 = _mm512_load_si512 (haystack + hay_index
> > >                                  + 1); // Always 64 byte aligned
> > > -      nullmask = _cvtmask64_u64 (_mm512_testn_epi8_mask (hay1, hay1));
> > > +      nullmask = cvtmask64_u64 (_mm512_testn_epi8_mask (hay1, hay1));
> > >        /* Compare only till null char */
> > >        cmpmask = nullmask ^ (nullmask - ONE_64BIT);
> > >        k0 = _mm512_cmpeq_epi8_mask (hay0, ned0);
> > >        k1 = _mm512_cmpeq_epi8_mask (hay1, ned1);
> > >        /* k2 masks tell us if both chars from needle match */
> > > -      k2 = _cvtmask64_u64 (_kand_mask64 (k0, k1)) & cmpmask;
> > > +      k2 = cvtmask64_u64 (_kand_mask64 (k0, k1)) & cmpmask;
> > >        /* For every match, compare full strings for potential match */
> > >        while (k2)
> > >          {
> > > --
> > > 2.34.1
> > >
> >
> > Sunil, can you see if this fixed the build issue with gcc6?
>
> Nope, there are more missing intrinsics
>
> ../sysdeps/x86_64/multiarch/strstr-avx512.c:144:8: error: implicit
> declaration of function ?_kshiftri_mask64? [-Wer
> ror=implicit-function-declaration]
> ../sysdeps/x86_64/multiarch/strstr-avx512.c:146:32: error: implicit
> declaration of function ?_kand_mask64? [-Werror
> =implicit-function-declaration]
> ../sysdeps/x86_64/multiarch/strstr-avx512.c:144:8: error: implicit
> declaration of function ?_kshiftri_mask64? [-Wer
> ror=implicit-function-declaration]
> ../sysdeps/x86_64/multiarch/strstr-avx512.c:146:32: error: implicit
> declaration of function ?_kand_mask64? [-Werror
> =implicit-function-declaration]

Oh sorry, didn't see those ones. Will have patch up in a second.