Re: [PATCH v2 2/2] x86: Add support for building str{c|p}{brk|spn} with explicit ISA level

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

On Wed, Jun 29, 2022 at 3:16 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Wed, Jun 29, 2022 at 3:05 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > The changes for these functions are different than the others because
> > the best implementation (sse4_2) requires the generic
> > implementation as a fallback to be built as well.
> >
> > Changes are:
> >
> > 1. Add non-multiarch functions for str{c|p}{brk|spn}.c to statically
> >    select the best implementation based on the configured ISA build
> >    level.
> >
> > 2. Add stubs for str{c|p}{brk|spn}-generic and varshift.c to in the
> >    sysdeps/x86_64 directory so that the the sse4 implementation will
> >    have all of its dependencies for the non-multiarch / rtld build
> >    when ISA level >= 2.
> >
> > 3. Add new multiarch/rtld-strcspn.c that just include the
> >    non-multiarch strcspn.c which will in turn select the best
> >    implementation based on the compiled ISA level.
> >
> > 4. Refactor the ifunc selector and ifunc implementation list to use
> >    the ISA level aware wrapper macros that allow functions below the
> >    compiled ISA level (with a guranteed replacement) to be skipped.
> >
> > Tested with and without multiarch on x86_64 for ISA levels:
> > {generic, x86-64-v2, x86-64-v3, x86-64-v4}
> >
> > And m32 with and without multiarch.
> > ---
> >  sysdeps/x86_64/Makefile                    |  9 +++++++-
> >  sysdeps/x86_64/multiarch/ifunc-impl-list.c |  6 +++++
> >  sysdeps/x86_64/multiarch/ifunc-sse4_2.h    |  2 +-
> >  sysdeps/x86_64/multiarch/rtld-strcspn.c    | 18 +++++++++++++++
> >  sysdeps/x86_64/multiarch/strcspn-generic.c |  6 +++--
> >  sysdeps/x86_64/multiarch/strcspn-sse4.c    |  6 +++--
> >  sysdeps/x86_64/multiarch/strpbrk-generic.c |  5 +++-
> >  sysdeps/x86_64/multiarch/strpbrk-sse4.c    |  6 ++++-
> >  sysdeps/x86_64/multiarch/strspn-generic.c  |  7 ++++--
> >  sysdeps/x86_64/multiarch/strspn-sse4.c     |  5 +++-
> >  sysdeps/x86_64/strcspn-generic.c           | 25 ++++++++++++++++++++
> >  sysdeps/x86_64/strcspn.c                   | 27 ++++++++++++++++++++++
> >  sysdeps/x86_64/strpbrk-generic.c           | 25 ++++++++++++++++++++
> >  sysdeps/x86_64/strpbrk.c                   | 27 ++++++++++++++++++++++
> >  sysdeps/x86_64/strspn-generic.c            | 26 +++++++++++++++++++++
> >  sysdeps/x86_64/strspn.c                    | 27 ++++++++++++++++++++++
> >  sysdeps/x86_64/varshift.c                  | 26 +++++++++++++++++++++
> >  17 files changed, 242 insertions(+), 11 deletions(-)
> >  create mode 100644 sysdeps/x86_64/multiarch/rtld-strcspn.c
> >  create mode 100644 sysdeps/x86_64/strcspn-generic.c
> >  create mode 100644 sysdeps/x86_64/strcspn.c
> >  create mode 100644 sysdeps/x86_64/strpbrk-generic.c
> >  create mode 100644 sysdeps/x86_64/strpbrk.c
> >  create mode 100644 sysdeps/x86_64/strspn-generic.c
> >  create mode 100644 sysdeps/x86_64/strspn.c
> >  create mode 100644 sysdeps/x86_64/varshift.c
> >
> > diff --git a/sysdeps/x86_64/Makefile b/sysdeps/x86_64/Makefile
> > index 79365aff2a..e597a4855f 100644
> > --- a/sysdeps/x86_64/Makefile
> > +++ b/sysdeps/x86_64/Makefile
> > @@ -14,7 +14,14 @@ sysdep_noprof += _mcount
> >  endif
> >
> >  ifeq ($(subdir),string)
> > -sysdep_routines += strcasecmp_l-nonascii strncase_l-nonascii
> > +sysdep_routines += \
> > +  strcasecmp_l-nonascii \
> > +  strcspn-generic \
> > +  strncase_l-nonascii \
> > +  strpbrk-generic \
> > +  strspn-generic \
> > +  varshift \
> > +# sysdep_routines
> >  gen-as-const-headers += locale-defines.sym
> >  tests += \
> >    tst-rsi-strlen
> > diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > index 0d28319905..6c03f53a8b 100644
> > --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > @@ -531,6 +531,8 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> >
> >    /* Support sysdeps/x86_64/multiarch/strcspn.c.  */
> >    IFUNC_IMPL (i, name, strcspn,
> > +             /* All implementations of strcspn are built at all ISA
> > +                levels.  */
> >               IFUNC_IMPL_ADD (array, i, strcspn, CPU_FEATURE_USABLE (SSE4_2),
> >                               __strcspn_sse42)
> >               IFUNC_IMPL_ADD (array, i, strcspn, 1, __strcspn_generic))
> > @@ -607,6 +609,8 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> >
> >    /* Support sysdeps/x86_64/multiarch/strpbrk.c.  */
> >    IFUNC_IMPL (i, name, strpbrk,
> > +             /* All implementations of strpbrk are built at all ISA
> > +                levels.  */
> >               IFUNC_IMPL_ADD (array, i, strpbrk, CPU_FEATURE_USABLE (SSE4_2),
> >                               __strpbrk_sse42)
> >               IFUNC_IMPL_ADD (array, i, strpbrk, 1, __strpbrk_generic))
> > @@ -614,6 +618,8 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> >
> >    /* Support sysdeps/x86_64/multiarch/strspn.c.  */
> >    IFUNC_IMPL (i, name, strspn,
> > +             /* All implementations of strspn are built at all ISA
> > +                levels.  */
> >               IFUNC_IMPL_ADD (array, i, strspn, CPU_FEATURE_USABLE (SSE4_2),
> >                               __strspn_sse42)
> >               IFUNC_IMPL_ADD (array, i, strspn, 1, __strspn_generic))
> > diff --git a/sysdeps/x86_64/multiarch/ifunc-sse4_2.h b/sysdeps/x86_64/multiarch/ifunc-sse4_2.h
> > index 973041d23b..f8943c8210 100644
> > --- a/sysdeps/x86_64/multiarch/ifunc-sse4_2.h
> > +++ b/sysdeps/x86_64/multiarch/ifunc-sse4_2.h
> > @@ -31,7 +31,7 @@ IFUNC_SELECTOR (void)
> >       there is no other optimized implementation keep using.  If an
> >       optimized fallback is added add a X86_ISA_CPU_FEATURE_ARCH_P
> >       (cpu_features, Slow_SSE4_2) check.  */
> > -  if (ISA_CPU_FEATURE_USABLE_P (cpu_features, SSE4_2))
> > +  if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, SSE4_2))
> >      return OPTIMIZE (sse42);
> >
> >    return OPTIMIZE (generic);
> > diff --git a/sysdeps/x86_64/multiarch/rtld-strcspn.c b/sysdeps/x86_64/multiarch/rtld-strcspn.c
> > new file mode 100644
> > index 0000000000..99e3c59e00
> > --- /dev/null
> > +++ b/sysdeps/x86_64/multiarch/rtld-strcspn.c
> > @@ -0,0 +1,18 @@
> > +/* Copyright (C) 2022 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include "../strcspn.c"
> > diff --git a/sysdeps/x86_64/multiarch/strcspn-generic.c b/sysdeps/x86_64/multiarch/strcspn-generic.c
> > index 423de2e2b2..86cda7b037 100644
> > --- a/sysdeps/x86_64/multiarch/strcspn-generic.c
> > +++ b/sysdeps/x86_64/multiarch/strcspn-generic.c
> > @@ -16,8 +16,10 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > -#if IS_IN (libc)
> > -
> > +/* We always need to build this implementation as strcspn-sse4 needs
> > +   to be able to fallback to it.  */
> > +#include <isa-level.h>
> > +#if IS_IN (libc) || MINIMUM_X86_ISA_LEVEL >= 2
> >  # include <sysdep.h>
> >  # define STRCSPN __strcspn_generic
> >
> > diff --git a/sysdeps/x86_64/multiarch/strcspn-sse4.c b/sysdeps/x86_64/multiarch/strcspn-sse4.c
> > index 59f64f9fe8..becdaf05f3 100644
> > --- a/sysdeps/x86_64/multiarch/strcspn-sse4.c
> > +++ b/sysdeps/x86_64/multiarch/strcspn-sse4.c
> > @@ -52,9 +52,11 @@
> >     when either CFlag or ZFlag is 1.  If CFlag == 1, ECX has the offset
> >     X for case 1.  */
> >
> > +#ifndef STRCSPN
> > +# define STRCSPN __strcspn_sse42
> > +#endif
> >  #ifndef STRCSPN_GENERIC
> >  # define STRCSPN_GENERIC __strcspn_generic
> > -# define STRCSPN_SSE42 __strcspn_sse42
> >  #endif
> >
> >  #ifdef USE_AS_STRPBRK
> > @@ -78,7 +80,7 @@ char *
> >  size_t
> >  #endif
> >  __attribute__ ((section (".text.sse4.2")))
> > -STRCSPN_SSE42 (const char *s, const char *a)
> > +STRCSPN (const char *s, const char *a)
> >  {
> >    if (*a == 0)
> >      RETURN (NULL, strlen (s));
> > diff --git a/sysdeps/x86_64/multiarch/strpbrk-generic.c b/sysdeps/x86_64/multiarch/strpbrk-generic.c
> > index d31acfe495..058f635774 100644
> > --- a/sysdeps/x86_64/multiarch/strpbrk-generic.c
> > +++ b/sysdeps/x86_64/multiarch/strpbrk-generic.c
> > @@ -16,8 +16,11 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > -#if IS_IN (libc)
> >
> > +/* We always need to build this implementation as strpbrk-sse4 needs
> > +   to be able to fallback to it.  */
> > +#include <isa-level.h>
> > +#if IS_IN (libc) || MINIMUM_X86_ISA_LEVEL >= 2
> >  # include <sysdep.h>
> >  # define STRPBRK __strpbrk_generic
> >
> > diff --git a/sysdeps/x86_64/multiarch/strpbrk-sse4.c b/sysdeps/x86_64/multiarch/strpbrk-sse4.c
> > index bf74d660d5..0adb577955 100644
> > --- a/sysdeps/x86_64/multiarch/strpbrk-sse4.c
> > +++ b/sysdeps/x86_64/multiarch/strpbrk-sse4.c
> > @@ -16,7 +16,11 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > +#ifndef STRPBRK
> > +# define STRPBRK __strpbrk_sse42
> > +#endif
> > +
> >  #define USE_AS_STRPBRK
> >  #define STRCSPN_GENERIC __strpbrk_generic
> > -#define STRCSPN_SSE42 __strpbrk_sse42
> > +#define STRCSPN STRPBRK
> >  #include "strcspn-sse4.c"
> > diff --git a/sysdeps/x86_64/multiarch/strspn-generic.c b/sysdeps/x86_64/multiarch/strspn-generic.c
> > index 6b50c36432..0f485ab4da 100644
> > --- a/sysdeps/x86_64/multiarch/strspn-generic.c
> > +++ b/sysdeps/x86_64/multiarch/strspn-generic.c
> > @@ -16,13 +16,16 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > -#if IS_IN (libc)
> > -
> > +/* We always need to build this implementation as strspn-sse4 needs to
> > +   be able to fallback to it.  */
> > +#include <isa-level.h>
> > +#if IS_IN (libc) || MINIMUM_X86_ISA_LEVEL >= 2
> >  # include <sysdep.h>
> >  # define STRSPN __strspn_generic
> >
> >  # undef libc_hidden_builtin_def
> >  # define libc_hidden_builtin_def(STRSPN)
> > +
> >  #endif
> >
> >  #include <string/strspn.c>
> > diff --git a/sysdeps/x86_64/multiarch/strspn-sse4.c b/sysdeps/x86_64/multiarch/strspn-sse4.c
> > index d044916688..4d50507a0d 100644
> > --- a/sysdeps/x86_64/multiarch/strspn-sse4.c
> > +++ b/sysdeps/x86_64/multiarch/strspn-sse4.c
> > @@ -53,10 +53,13 @@
> >
> >  extern size_t __strspn_generic (const char *, const char *) attribute_hidden;
> >
> > +#ifndef STRSPN
> > +# define STRSPN        __strspn_sse42
> > +#endif
> >
> >  size_t
> >  __attribute__ ((section (".text.sse4.2")))
> > -__strspn_sse42 (const char *s, const char *a)
> > +STRSPN (const char *s, const char *a)
> >  {
> >    if (*a == 0)
> >      return 0;
> > diff --git a/sysdeps/x86_64/strcspn-generic.c b/sysdeps/x86_64/strcspn-generic.c
> > new file mode 100644
> > index 0000000000..51fd70b63d
> > --- /dev/null
> > +++ b/sysdeps/x86_64/strcspn-generic.c
> > @@ -0,0 +1,25 @@
> > +/* Hook for build strcspn-generic for non-multiarch build.  Needed for
> > +   the ISA level >= 2 because strcspn-sse4 has a dependency on
> > +   strcspn-generic.
> > +   Copyright (C) 2022 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <isa-level.h>
> > +
> > +#if MINIMUM_X86_ISA_LEVEL >= 2
> > +# include "multiarch/strcspn-generic.c"
> > +#endif
> > diff --git a/sysdeps/x86_64/strcspn.c b/sysdeps/x86_64/strcspn.c
> > new file mode 100644
> > index 0000000000..cd54eed869
> > --- /dev/null
> > +++ b/sysdeps/x86_64/strcspn.c
> > @@ -0,0 +1,27 @@
> > +/* strcspn hook for non-multiarch and RTLD build.
> > +   Copyright (C) 2022 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <isa-level.h>
> > +
> > +#if MINIMUM_X86_ISA_LEVEL == 1
> > +#include <string/strcspn.c>
> > +#else
> > +#define STRCSPN        strcspn
> > +#include "multiarch/strcspn-sse4.c"
> > +libc_hidden_builtin_def (strcspn)
> > +#endif
> > diff --git a/sysdeps/x86_64/strpbrk-generic.c b/sysdeps/x86_64/strpbrk-generic.c
> > new file mode 100644
> > index 0000000000..a7d8b11216
> > --- /dev/null
> > +++ b/sysdeps/x86_64/strpbrk-generic.c
> > @@ -0,0 +1,25 @@
> > +/* Hook for build strpbrk-generic for non-multiarch build.  Needed for
> > +   the ISA level >= 2 because strpbrk-sse4 has a dependency on
> > +   strpbrk-generic.
> > +   Copyright (C) 2022 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <isa-level.h>
> > +
> > +#if MINIMUM_X86_ISA_LEVEL >= 2
> > +# include "multiarch/strpbrk-generic.c"
> > +#endif
> > diff --git a/sysdeps/x86_64/strpbrk.c b/sysdeps/x86_64/strpbrk.c
> > new file mode 100644
> > index 0000000000..e7ea1b334a
> > --- /dev/null
> > +++ b/sysdeps/x86_64/strpbrk.c
> > @@ -0,0 +1,27 @@
> > +/* strpbrk hook for non-multiarch and RTLD build.
> > +   Copyright (C) 2022 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <isa-level.h>
> > +
> > +#if MINIMUM_X86_ISA_LEVEL == 1
> > +#include <string/strpbrk.c>
> > +#else
> > +#define STRPBRK        strpbrk
> > +#include "multiarch/strpbrk-sse4.c"
> > +libc_hidden_builtin_def (strpbrk)
> > +#endif
> > diff --git a/sysdeps/x86_64/strspn-generic.c b/sysdeps/x86_64/strspn-generic.c
> > new file mode 100644
> > index 0000000000..1a2a576e49
> > --- /dev/null
> > +++ b/sysdeps/x86_64/strspn-generic.c
> > @@ -0,0 +1,26 @@
> > +/* Hook for build strspn-generic for non-multiarch build.  Needed for
> > +   the ISA level >= 2 because strspn-sse4 has a dependency on
> > +   strspn-generic.
> > +   Copyright (C) 2022 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +
> > +#include <isa-level.h>
> > +
> > +#if MINIMUM_X86_ISA_LEVEL >= 2
> > +# include "multiarch/strspn-generic.c"
> > +#endif
> > diff --git a/sysdeps/x86_64/strspn.c b/sysdeps/x86_64/strspn.c
> > new file mode 100644
> > index 0000000000..7b9ede26d9
> > --- /dev/null
> > +++ b/sysdeps/x86_64/strspn.c
> > @@ -0,0 +1,27 @@
> > +/* strspn hook for non-multiarch and RTLD build.
> > +   Copyright (C) 2022 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +#include <isa-level.h>
> > +
> > +#if MINIMUM_X86_ISA_LEVEL == 1
> > +#include <string/strspn.c>
> > +#else
> > +#define STRSPN strspn
> > +#include "multiarch/strspn-sse4.c"
> > +libc_hidden_builtin_def (strspn)
> > +#endif
> > diff --git a/sysdeps/x86_64/varshift.c b/sysdeps/x86_64/varshift.c
> > new file mode 100644
> > index 0000000000..8f9eb13547
> > --- /dev/null
> > +++ b/sysdeps/x86_64/varshift.c
> > @@ -0,0 +1,26 @@
> > +/* Hook for build varshift for non-multiarch build.  Needed for the
> > +   ISA level >= 2 because strspn-sse4, strcspn-sse4, and strpbrk-sse4
> > +   all have a dependency on varshift.c.
> > +   Copyright (C) 2022 Free Software Foundation, Inc.
> > +   This file is part of the GNU C Library.
> > +
> > +   The GNU C Library is free software; you can redistribute it and/or
> > +   modify it under the terms of the GNU Lesser General Public
> > +   License as published by the Free Software Foundation; either
> > +   version 2.1 of the License, or (at your option) any later version.
> > +
> > +   The GNU C Library is distributed in the hope that it will be useful,
> > +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > +   Lesser General Public License for more details.
> > +
> > +   You should have received a copy of the GNU Lesser General Public
> > +   License along with the GNU C Library; if not, see
> > +   <https://www.gnu.org/licenses/>.  */
> > +
> > +
> > +#include <isa-level.h>
> > +
> > +#if MINIMUM_X86_ISA_LEVEL >= 2
> > +# include "multiarch/varshift.c"
> > +#endif
> > --
> > 2.34.1
> >
>
> LGTM.
>
> Thanks.
>
> --
> H.J.

Rebsubmitted in V5 after rebase ontop of:

commit 0aa294fb887bb5aae4cdfa4b764325466a329131
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Wed Jun 29 18:56:17 2022 -0700

    x86: Add missing IS_IN (libc) check to strcspn-sse4.c