[PATCH v1] x86: Add EVEX optimized memchr family not safe for RTM

H.J. Lu hjl.tools@gmail.com
Thu May 6 13:38:57 GMT 2021


On Tue, May 04, 2021 at 07:32:28PM -0400, Noah Goldstein wrote:
> No bug.
> 
> This commit adds a new implementation for EVEX memchr that is not safe
> for RTM because it uses vzeroupper. The benefit is that by using
> ymm0-ymm15 it can use vpcmpeq and vpternlogd in the 4x loop which is
> faster than the RTM safe version which cannot use vpcmpeq because
> there is no EVEX encoding for the instruction. All parts of the
> implementation aside from the 4x loop are the same for the two
> versions and the optimization is only relevant for large sizes.
> 
> Tigerlake:
> size  , algn  , Pos   , Cur T , New T , Win     , Dif
> 512   , 6     , 192   , 9.2   , 9.04  , no-RTM  , 0.16
> 512   , 7     , 224   , 9.19  , 8.98  , no-RTM  , 0.21
> 2048  , 0     , 256   , 10.74 , 10.54 , no-RTM  , 0.2
> 2048  , 0     , 512   , 14.81 , 14.87 , RTM     , 0.06
> 2048  , 0     , 1024  , 22.97 , 22.57 , no-RTM  , 0.4
> 2048  , 0     , 2048  , 37.49 , 34.51 , no-RTM  , 2.98   <--
> 
> Icelake:
> size  , algn  , Pos   , Cur T , New T , Win     , Dif
> 512   , 6     , 192   , 7.6   , 7.3   , no-RTM  , 0.3
> 512   , 7     , 224   , 7.63  , 7.27  , no-RTM  , 0.36
> 2048  , 0     , 256   , 8.48  , 8.38  , no-RTM  , 0.1
> 2048  , 0     , 512   , 11.57 , 11.42 , no-RTM  , 0.15
> 2048  , 0     , 1024  , 17.92 , 17.38 , no-RTM  , 0.54
> 2048  , 0     , 2048  , 30.37 , 27.34 , no-RTM  , 3.03   <--
> 
> test-memchr, test-wmemchr, and test-rawmemchr are all passing.
> 
> Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
> ---
> Two things worth noting.
> 
> 1) There are few other files where this may be relevant so it may be
> better to replace ifunc-memchr.h with something more generic (mostly
> strchr, strcmp and memcmp in mind)
> 
> 2) It may be better to just use the RTM safe method used in the
> avx2-rtm family for this. I don't have any machines that support intel
> TSX to test it but my fear was that the overhead on the shorter cases
> would make it not worth it (i.e for alignment = 0, sizes around [160,
> 288] or lengths around [288, 416])
>         
>  sysdeps/x86_64/multiarch/Makefile             |   7 +-
>  sysdeps/x86_64/multiarch/ifunc-impl-list.c    |  18 ++
>  sysdeps/x86_64/multiarch/ifunc-memchr.h       |  54 ++++++
>  sysdeps/x86_64/multiarch/memchr-evex-rtm.S    |   8 +
>  sysdeps/x86_64/multiarch/memchr-evex.S        | 160 ++++++++++++++----
>  sysdeps/x86_64/multiarch/memchr.c             |   2 +-
>  sysdeps/x86_64/multiarch/rawmemchr-evex-rtm.S |   3 +
>  sysdeps/x86_64/multiarch/rawmemchr.c          |   2 +-
>  sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S   |   3 +
>  sysdeps/x86_64/multiarch/wmemchr.c            |   2 +-
>  10 files changed, 219 insertions(+), 40 deletions(-)
>  create mode 100644 sysdeps/x86_64/multiarch/ifunc-memchr.h
>  create mode 100644 sysdeps/x86_64/multiarch/memchr-evex-rtm.S
>  create mode 100644 sysdeps/x86_64/multiarch/rawmemchr-evex-rtm.S
>  create mode 100644 sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S
> 
> diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
> index 491c7698dc..2c2aad3a7e 100644
> --- a/sysdeps/x86_64/multiarch/Makefile
> +++ b/sysdeps/x86_64/multiarch/Makefile
> @@ -77,7 +77,9 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c \
>  		   strncmp-evex \
>  		   strncpy-evex \
>  		   strnlen-evex \
> -		   strrchr-evex
> +		   strrchr-evex \
> +		   memchr-evex-rtm \
> +		   rawmemchr-evex-rtm

Please group EVEX files and sort them by names.

>  CFLAGS-varshift.c += -msse4
>  CFLAGS-strcspn-c.c += -msse4
>  CFLAGS-strpbrk-c.c += -msse4
> @@ -110,7 +112,8 @@ sysdep_routines += wmemcmp-sse4 wmemcmp-ssse3 wmemcmp-c \
>  		   wcsnlen-evex \
>  		   wcsrchr-evex \
>  		   wmemchr-evex \
> -		   wmemcmp-evex-movbe
> +		   wmemcmp-evex-movbe \
> +		   wmemchr-evex-rtm

Please group EVEX files and sort them by names.

>  endif
>  
>  ifeq ($(subdir),debug)
> diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> index 651b32908e..b3c4ad286d 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> @@ -52,6 +52,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>  			       && CPU_FEATURE_USABLE (AVX512BW)
>  			       && CPU_FEATURE_USABLE (BMI2)),
>  			      __memchr_evex)
> +	      IFUNC_IMPL_ADD (array, i, memchr,
> +			      (CPU_FEATURE_USABLE (AVX512VL)
> +			       && CPU_FEATURE_USABLE (AVX512BW)
> +			       && CPU_FEATURE_USABLE (BMI2)
> +			       && CPU_FEATURE_USABLE (RTM)),
> +			      __memchr_evex_rtm)
>  	      IFUNC_IMPL_ADD (array, i, memchr, 1, __memchr_sse2))
>  
>    /* Support sysdeps/x86_64/multiarch/memcmp.c.  */
> @@ -288,6 +294,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>  			       && CPU_FEATURE_USABLE (AVX512BW)
>  			       && CPU_FEATURE_USABLE (BMI2)),
>  			      __rawmemchr_evex)
> +	      IFUNC_IMPL_ADD (array, i, rawmemchr,
> +			      (CPU_FEATURE_USABLE (AVX512VL)
> +			       && CPU_FEATURE_USABLE (AVX512BW)
> +			       && CPU_FEATURE_USABLE (BMI2)
> +			       && CPU_FEATURE_USABLE (RTM)),
> +			      __rawmemchr_evex_rtm)
>  	      IFUNC_IMPL_ADD (array, i, rawmemchr, 1, __rawmemchr_sse2))
>  
>    /* Support sysdeps/x86_64/multiarch/strlen.c.  */
> @@ -708,6 +720,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>  			       && CPU_FEATURE_USABLE (AVX512BW)
>  			       && CPU_FEATURE_USABLE (BMI2)),
>  			      __wmemchr_evex)
> +	      IFUNC_IMPL_ADD (array, i, wmemchr,
> +			      (CPU_FEATURE_USABLE (AVX512VL)
> +			       && CPU_FEATURE_USABLE (AVX512BW)
> +			       && CPU_FEATURE_USABLE (BMI2)
> +			       && CPU_FEATURE_USABLE (RTM)),
> +			      __wmemchr_evex_rtm)
>  	      IFUNC_IMPL_ADD (array, i, wmemchr, 1, __wmemchr_sse2))
>  
>    /* Support sysdeps/x86_64/multiarch/wmemcmp.c.  */
> diff --git a/sysdeps/x86_64/multiarch/ifunc-memchr.h b/sysdeps/x86_64/multiarch/ifunc-memchr.h
> new file mode 100644
> index 0000000000..61a1f6e179
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/ifunc-memchr.h

If the similar optimization may be applied on other functions,
please rename it to ifunc-evex.h.

> @@ -0,0 +1,54 @@
> +/* Common definition for memchr/rawmemchr/wmemchr ifunc selections.
> +   All versions must be listed in ifunc-impl-list.c.
> +   Copyright (C) 2017-2021 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 <init-arch.h>
> +
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_rtm) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (evex) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (evex_rtm) attribute_hidden;
> +
> +static inline void *
> +IFUNC_SELECTOR (void)
> +{
> +  const struct cpu_features* cpu_features = __get_cpu_features ();
> +
> +  if (CPU_FEATURE_USABLE_P (cpu_features, AVX2)
> +      && CPU_FEATURE_USABLE_P (cpu_features, BMI2)
> +      && CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
> +    {
> +      if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
> +          && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
> +      {
> +          if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
> +              return OPTIMIZE (evex_rtm);
> +
> +          return OPTIMIZE (evex);
> +      }
> +
> +      if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
> +          return OPTIMIZE (avx2_rtm);
> +
> +      if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
> +          return OPTIMIZE (avx2);

Please fix indentations for lines above.

> +    }
> +
> +  return OPTIMIZE (sse2);
> +}
> diff --git a/sysdeps/x86_64/multiarch/memchr-evex-rtm.S b/sysdeps/x86_64/multiarch/memchr-evex-rtm.S
> new file mode 100644
> index 0000000000..1987188271
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/memchr-evex-rtm.S
> @@ -0,0 +1,8 @@
> +#ifndef MEMCHR
> +# define MEMCHR __memchr_evex_rtm
> +#endif
> +
> +#define USE_IN_RTM 1
> +#define SECTION(p) p##.evex.rtm
> +
> +#include "memchr-evex.S"
> diff --git a/sysdeps/x86_64/multiarch/memchr-evex.S b/sysdeps/x86_64/multiarch/memchr-evex.S
> index 81d5cd6486..c938594bc3 100644
> --- a/sysdeps/x86_64/multiarch/memchr-evex.S
> +++ b/sysdeps/x86_64/multiarch/memchr-evex.S
> @@ -38,10 +38,32 @@
>  #  define CHAR_SIZE	1
>  # endif
>  
> +	/* In the 4x loop the RTM and non-RTM versions have data pointer
> +	   off by VEC_SIZE * 4 with RTM version being VEC_SIZE * 4 greater.
> +	   This is represented by BASE_OFFSET. As well because the RTM
> +	   version uses vpcmp which stores a bit per element compared where
> +	   the non-RTM version uses vpcmpeq which stores a bit per byte
> +	   compared RET_SCALE of CHAR_SIZE is only relevant for the RTM
> +	   version.  */
> +# ifdef USE_IN_RTM
> +#  define VZEROUPPER
> +#  define BASE_OFFSET	(VEC_SIZE * 4)
> +#  define RET_SCALE	CHAR_SIZE
> +# else
> +#  define VZEROUPPER	vzeroupper
> +#  define BASE_OFFSET	0
> +#  define RET_SCALE	1
> +# endif
> +
> +	/* In the return from 4x loop memchr and rawmemchr versions have
> +	   data pointers off by VEC_SIZE * 4 with memchr version being
> +	   VEC_SIZE * 4 greater.  */
>  # ifdef USE_AS_RAWMEMCHR
> +#  define RET_OFFSET	(BASE_OFFSET - (VEC_SIZE * 4))
>  #  define RAW_PTR_REG	rcx
>  #  define ALGN_PTR_REG	rdi
>  # else
> +#  define RET_OFFSET	BASE_OFFSET
>  #  define RAW_PTR_REG	rdi
>  #  define ALGN_PTR_REG	rcx
>  # endif
> @@ -57,11 +79,15 @@
>  # define YMM5		ymm21
>  # define YMM6		ymm22
>  
> +# ifndef SECTION
> +#  define SECTION(p)	p##.evex
> +# endif
> +
>  # define VEC_SIZE 32
>  # define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE)
>  # define PAGE_SIZE 4096
>  
> -	.section .text.evex,"ax",@progbits
> +	.section SECTION(.text),"ax",@progbits
>  ENTRY (MEMCHR)
>  # ifndef USE_AS_RAWMEMCHR
>  	/* Check for zero length.  */
> @@ -237,14 +263,15 @@ L(cross_page_continue):
>  	/* Check if at last CHAR_PER_VEC * 4 length.  */
>  	subq	$(CHAR_PER_VEC * 4), %rdx
>  	jbe	L(last_4x_vec_or_less_cmpeq)
> -	addq	$VEC_SIZE, %rdi
> +	/* +VEC_SIZE if USE_IN_RTM otherwise +VEC_SIZE * 5.  */
> +	addq	$(VEC_SIZE + (VEC_SIZE * 4 - BASE_OFFSET)), %rdi
>  
>  	/* Align data to VEC_SIZE * 4 for the loop and readjust length.
>  	 */
>  #  ifdef USE_AS_WMEMCHR
>  	movl	%edi, %ecx
>  	andq	$-(4 * VEC_SIZE), %rdi
> -	andl	$(VEC_SIZE * 4 - 1), %ecx
> +	subl	%edi, %ecx
>  	/* NB: Divide bytes by 4 to get the wchar_t count.  */
>  	sarl	$2, %ecx
>  	addq	%rcx, %rdx
> @@ -254,15 +281,28 @@ L(cross_page_continue):
>  	subq	%rdi, %rdx
>  #  endif
>  # else
> -	addq	$VEC_SIZE, %rdi
> +	addq	$(VEC_SIZE + (VEC_SIZE * 4 - BASE_OFFSET)), %rdi
>  	andq	$-(4 * VEC_SIZE), %rdi
>  # endif
> -
> +# ifdef USE_IN_RTM
>  	vpxorq	%XMMZERO, %XMMZERO, %XMMZERO
> +# else
> +	/* copy ymmmatch to ymm0 so we can use vpcmpeq which is not
> +	   encodable with EVEX registers (ymm16-ymm31).  */
> +	vmovdqa64 %YMMMATCH, %ymm0
> +# endif
>  
>  	/* Compare 4 * VEC at a time forward.  */
>  	.p2align 4
>  L(loop_4x_vec):
> +	/* Two versions of the loop. One that does not require
> +	   vzeroupper by not using ymm0-ymm15 and another does that require
> +	   vzeroupper because it uses ymm0-ymm15. The reason why ymm0-ymm15
> +	   is used at all is because there is no EVEX encoding vpcmpeq and
> +	   with vpcmpeq this loop can be performed more efficiently. The
> +	   non-vzeroupper version is safe for RTM while the vzeroupper
> +	   version should be prefered if RTM are not supported.  */
> +# ifdef USE_IN_RTM
>  	/* It would be possible to save some instructions using 4x VPCMP
>  	   but bottleneck on port 5 makes it not woth it.  */
>  	VPCMP	$4, (VEC_SIZE * 4)(%rdi), %YMMMATCH, %k1
> @@ -273,12 +313,55 @@ L(loop_4x_vec):
>  	/* Reduce VEC2 / VEC3 with min and VEC1 with zero mask.  */
>  	VPMINU	%YMM2, %YMM3, %YMM3 {%k1} {z}
>  	VPCMP	$0, %YMM3, %YMMZERO, %k2
> +# else
> +	/* Since vptern can only take 3x vectors fastest to do 1 vec
> +	   seperately with EVEX vpcmp.  */
> +#  ifdef USE_AS_WMEMCHR
> +	/* vptern can only accept masks for epi32/epi64 so can only save
> +	   instruction using not equals mask on vptern with wmemchr.  */
> +	VPCMP	$4, (%rdi), %YMMMATCH, %k1
> +#  else
> +	VPCMP	$0, (%rdi), %YMMMATCH, %k1
> +#  endif
> +	/* Compare 3x with vpcmpeq and or them all together with vptern.
> +	 */
> +	VPCMPEQ	VEC_SIZE(%rdi), %ymm0, %ymm2
> +	VPCMPEQ	(VEC_SIZE * 2)(%rdi), %ymm0, %ymm3
> +	VPCMPEQ	(VEC_SIZE * 3)(%rdi), %ymm0, %ymm4
> +#  ifdef USE_AS_WMEMCHR
> +	/* This takes the not of or between ymm2, ymm3, ymm4 as well as
> +	   combines result from VEC0 with zero mask.  */
> +	vpternlogd $1, %ymm2, %ymm3, %ymm4 {%k1} {z}
> +	vpmovmskb %ymm4, %ecx
> +#  else
> +	/* 254 is mask for oring ymm2, ymm3, ymm4 into ymm4.  */
> +	vpternlogd $254, %ymm2, %ymm3, %ymm4
> +	vpmovmskb %ymm4, %ecx
> +	kmovd	%k1, %eax
> +#  endif
> +# endif
> +
>  # ifdef USE_AS_RAWMEMCHR
>  	subq	$-(VEC_SIZE * 4), %rdi
> +# endif
> +# ifdef USE_IN_RTM
>  	kortestd %k2, %k3
> +# else
> +#  ifdef USE_AS_WMEMCHR
> +	/* ecx contains not of matches. All 1s means no matches. incl will
> +	   overflow and set zeroflag if that is the case.  */
> +	incl	%ecx
> +#  else
> +	/* If either VEC1 (eax) or VEC2-VEC4 (ecx) are not zero. Adding
> +	   to ecx is not an issue because if eax is non-zero it will be
> +	   used for returning the match. If it is zero the add does
> +	   nothing.  */
> +	addq	%rax, %rcx
> +#  endif
> +# endif
> +# ifdef USE_AS_RAWMEMCHR
>  	jz	L(loop_4x_vec)
>  # else
> -	kortestd %k2, %k3
>  	jnz	L(loop_4x_vec_end)
>  
>  	subq	$-(VEC_SIZE * 4), %rdi
> @@ -288,9 +371,11 @@ L(loop_4x_vec):
>  
>  	/* Fall through into less than 4 remaining vectors of length case.
>  	 */
> -	VPCMP	$0, (VEC_SIZE * 4)(%rdi), %YMMMATCH, %k0
> +	VPCMP	$0, BASE_OFFSET(%rdi), %YMMMATCH, %k0
> +	addq	$(BASE_OFFSET - VEC_SIZE), %rdi
>  	kmovd	%k0, %eax
> -	addq	$(VEC_SIZE * 3), %rdi
> +	VZEROUPPER
> +
>  	.p2align 4

I think this ".p2align 4" can be removed since it isn't in a loop.

>  L(last_4x_vec_or_less):
>  	/* Check if first VEC contained match.  */
> @@ -338,73 +423,78 @@ L(loop_4x_vec_end):
>  	/* rawmemchr will fall through into this if match was found in
>  	   loop.  */
>  
> +# if defined USE_IN_RTM || defined USE_AS_WMEMCHR
>  	/* k1 has not of matches with VEC1.  */
>  	kmovd	%k1, %eax
> -# ifdef USE_AS_WMEMCHR
> +#  ifdef USE_AS_WMEMCHR
>  	subl	$((1 << CHAR_PER_VEC) - 1), %eax
> -# else
> +#  else
>  	incl	%eax
> +#  endif
> +# else
> +	/* eax already has matches for VEC1.  */
> +	testl	%eax, %eax
>  # endif
>  	jnz	L(last_vec_x1_return)
>  
> +# ifdef USE_IN_RTM
>  	VPCMP	$0, %YMM2, %YMMZERO, %k0
>  	kmovd	%k0, %eax
> +# else
> +	vpmovmskb %ymm2, %eax
> +# endif
>  	testl	%eax, %eax
>  	jnz	L(last_vec_x2_return)
>  
> +# ifdef USE_IN_RTM
>  	kmovd	%k2, %eax
>  	testl	%eax, %eax
>  	jnz	L(last_vec_x3_return)
>  
>  	kmovd	%k3, %eax
>  	tzcntl	%eax, %eax
> -# ifdef USE_AS_RAWMEMCHR
> -	leaq	(VEC_SIZE * 3)(%rdi, %rax, CHAR_SIZE), %rax
> +	leaq	(VEC_SIZE * 3 + RET_OFFSET)(%rdi, %rax, CHAR_SIZE), %rax
>  # else
> -	leaq	(VEC_SIZE * 7)(%rdi, %rax, CHAR_SIZE), %rax
> +	vpmovmskb %ymm3, %eax
> +	/* Combine matches in VEC3 (eax) with matches in VEC4 (ecx).  */
> +	salq	$VEC_SIZE, %rcx
> +	orq	%rcx, %rax
> +	tzcntq	%rax, %rax
> +	leaq	(VEC_SIZE * 2 + RET_OFFSET)(%rdi, %rax), %rax
> +	VZEROUPPER
>  # endif
>  	ret
>  
>  	.p2align 4
>  L(last_vec_x1_return):
>  	tzcntl	%eax, %eax
> -# ifdef USE_AS_RAWMEMCHR
> -#  ifdef USE_AS_WMEMCHR
> +# if defined USE_AS_WMEMCHR || RET_OFFSET != 0
>  	/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count.  */
> -	leaq	(%rdi, %rax, CHAR_SIZE), %rax
> -#  else
> -	addq	%rdi, %rax
> -#  endif
> +	leaq	RET_OFFSET(%rdi, %rax, CHAR_SIZE), %rax
>  # else
> -	/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count.  */
> -	leaq	(VEC_SIZE * 4)(%rdi, %rax, CHAR_SIZE), %rax
> +	addq	%rdi, %rax
>  # endif
> +	VZEROUPPER
>  	ret
>  
>  	.p2align 4
>  L(last_vec_x2_return):
>  	tzcntl	%eax, %eax
> -# ifdef USE_AS_RAWMEMCHR
> -	/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count.  */
> -	leaq	VEC_SIZE(%rdi, %rax, CHAR_SIZE), %rax
> -# else
> -	/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count.  */
> -	leaq	(VEC_SIZE * 5)(%rdi, %rax, CHAR_SIZE), %rax
> -# endif
> +	/* NB: Multiply bytes by RET_SCALE to get the wchar_t count
> +	   if relevant (RET_SCALE = CHAR_SIZE if USE_AS_WMEMCHAR and
> +	   USE_IN_RTM are both defined. Otherwise RET_SCALE = 1.  */
> +	leaq	(VEC_SIZE + RET_OFFSET)(%rdi, %rax, RET_SCALE), %rax
> +	VZEROUPPER
>  	ret
>  
> +# ifdef USE_IN_RTM
>  	.p2align 4
>  L(last_vec_x3_return):
>  	tzcntl	%eax, %eax
> -# ifdef USE_AS_RAWMEMCHR
> -	/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count.  */
> -	leaq	(VEC_SIZE * 2)(%rdi, %rax, CHAR_SIZE), %rax
> -# else
>  	/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count.  */
> -	leaq	(VEC_SIZE * 6)(%rdi, %rax, CHAR_SIZE), %rax
> -# endif
> +	leaq	(VEC_SIZE * 2 + RET_OFFSET)(%rdi, %rax, CHAR_SIZE), %rax
>  	ret
> -
> +# endif
>  
>  # ifndef USE_AS_RAWMEMCHR
>  L(last_4x_vec_or_less_cmpeq):
> diff --git a/sysdeps/x86_64/multiarch/memchr.c b/sysdeps/x86_64/multiarch/memchr.c
> index 6ad94f5775..37b088e5be 100644
> --- a/sysdeps/x86_64/multiarch/memchr.c
> +++ b/sysdeps/x86_64/multiarch/memchr.c
> @@ -24,7 +24,7 @@
>  # undef memchr
>  
>  # define SYMBOL_NAME memchr
> -# include "ifunc-avx2.h"
> +# include "ifunc-memchr.h"
>  
>  libc_ifunc_redirected (__redirect_memchr, memchr, IFUNC_SELECTOR ());
>  strong_alias (memchr, __memchr)
> diff --git a/sysdeps/x86_64/multiarch/rawmemchr-evex-rtm.S b/sysdeps/x86_64/multiarch/rawmemchr-evex-rtm.S
> new file mode 100644
> index 0000000000..deda1ca395
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/rawmemchr-evex-rtm.S
> @@ -0,0 +1,3 @@
> +#define MEMCHR __rawmemchr_evex_rtm
> +#define USE_AS_RAWMEMCHR 1
> +#include "memchr-evex-rtm.S"
> diff --git a/sysdeps/x86_64/multiarch/rawmemchr.c b/sysdeps/x86_64/multiarch/rawmemchr.c
> index 8ef2468400..01e5be080c 100644
> --- a/sysdeps/x86_64/multiarch/rawmemchr.c
> +++ b/sysdeps/x86_64/multiarch/rawmemchr.c
> @@ -26,7 +26,7 @@
>  # undef __rawmemchr
>  
>  # define SYMBOL_NAME rawmemchr
> -# include "ifunc-avx2.h"
> +# include "ifunc-memchr.h"
>  
>  libc_ifunc_redirected (__redirect_rawmemchr, __rawmemchr,
>  		       IFUNC_SELECTOR ());
> diff --git a/sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S b/sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S
> new file mode 100644
> index 0000000000..5d568c5cb7
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S
> @@ -0,0 +1,3 @@
> +#define MEMCHR __wmemchr_evex_rtm
> +#define USE_AS_WCSCHR 1
> +#include "memchr-evex-rtm.S"
> diff --git a/sysdeps/x86_64/multiarch/wmemchr.c b/sysdeps/x86_64/multiarch/wmemchr.c
> index 393d520658..ba108b8672 100644
> --- a/sysdeps/x86_64/multiarch/wmemchr.c
> +++ b/sysdeps/x86_64/multiarch/wmemchr.c
> @@ -26,7 +26,7 @@
>  # undef __wmemchr
>  
>  # define SYMBOL_NAME wmemchr
> -# include "ifunc-avx2.h"
> +# include "ifunc-memchr.h"
>  
>  libc_ifunc_redirected (__redirect_wmemchr, __wmemchr, IFUNC_SELECTOR ());
>  weak_alias (__wmemchr, wmemchr)
> -- 
> 2.29.2
> 

Thanks.

H.J.


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