From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vs1-xe34.google.com (mail-vs1-xe34.google.com [IPv6:2607:f8b0:4864:20::e34]) by sourceware.org (Postfix) with ESMTPS id D88553858D28; Wed, 27 Apr 2022 23:58:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org D88553858D28 Received: by mail-vs1-xe34.google.com with SMTP id z144so3136781vsz.13; Wed, 27 Apr 2022 16:58:11 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=FEvonSzHxeQ26IwQM5Go5u2LlxJhlvJMx4qjz/ZfzdA=; b=GostwUrDsVSPCSZpI6TPj3vvtk3iGJKsVOrLnXM5z2ixbIWFr0YdLLJAikXPX+U1B4 qNOuLxPR6mRCTW9C7bAh884QPUDVmo7JY7yQZmEezVRfE8JwCXPJCtnAANe2je+OQPS+ EwwZQhsS5i7oqa3hAyvJG2OiM1mO/9qG0EsF6FVXe6On8tcifO68KFkZP5Wqu9RONLXf b58b9SqdQt4oCNP/tQttJH6zbxVCmPKxTbnP/ujToHUZ+w+Qnc3QoIT0/EgXw1SkAFm/ iKlt97dzxR/EyDxeg6o5nqGdS5aEJN9hWX2Q6ewZ3oG9ITg/cq8DhqVRyS9DW/7xFPWU kQRA== X-Gm-Message-State: AOAM533q1QQkLC/Cnle0cC3mFc0uw+NoREavPYvfw85TVi999OBwhefZ HiJvjCVcfuCQBPYDX0BNcYcgB1uxRQOA605uQ5D2WMnnWjI= X-Google-Smtp-Source: ABdhPJz5xWAJIQtC8mINCr2rpL5TD39Ei1hlx79UlmHBqTvwZNBJYXm/xOTGvarb4OP5DNRQvEYuWFjhUOFBrGWkrlc= X-Received: by 2002:a67:ee4f:0:b0:32c:ee75:6e98 with SMTP id g15-20020a67ee4f000000b0032cee756e98mr2731277vsp.79.1651103891066; Wed, 27 Apr 2022 16:58:11 -0700 (PDT) MIME-Version: 1.0 References: <20210504233226.1514601-1-goldstein.w.n@gmail.com> <20210508040605.2892960-1-goldstein.w.n@gmail.com> In-Reply-To: From: Sunil Pandey Date: Wed, 27 Apr 2022 16:57:35 -0700 Message-ID: Subject: Re: [PATCH v4] x86: Add EVEX optimized memchr family not safe for RTM To: "H.J. Lu" , libc-stable@sourceware.org Cc: Noah Goldstein , GNU C Library Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-6.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM, GIT_PATCH_0, HK_RANDOM_ENVFROM, HK_RANDOM_FROM, KAM_SHORT, KAM_STOCKGEN, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-stable@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-stable mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Apr 2022 23:58:15 -0000 On Sat, May 8, 2021 at 7:03 AM H.J. Lu via Libc-alpha wrote: > > On Sat, May 08, 2021 at 12:06:05AM -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 > > --- > > sysdeps/x86_64/multiarch/Makefile | 7 +- > > sysdeps/x86_64/multiarch/ifunc-evex.h | 55 ++++++ > > sysdeps/x86_64/multiarch/ifunc-impl-list.c | 15 ++ > > sysdeps/x86_64/multiarch/memchr-evex-rtm.S | 8 + > > sysdeps/x86_64/multiarch/memchr-evex.S | 161 ++++++++++++++---- > > 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, 217 insertions(+), 41 deletions(-) > > create mode 100644 sysdeps/x86_64/multiarch/ifunc-evex.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 > > 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 > > endif > > > > ifeq ($(subdir),debug) > > diff --git a/sysdeps/x86_64/multiarch/ifunc-evex.h b/sysdeps/x86_64/multiarch/ifunc-evex.h > > new file mode 100644 > > index 0000000000..fc391edb8a > > --- /dev/null > > +++ b/sysdeps/x86_64/multiarch/ifunc-evex.h > > @@ -0,0 +1,55 @@ > > +/* Common definition for ifunc selection optimized with EVEX. > > + 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 > > + . */ > > + > > +#include > > + > > +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); > > + } > > + > > + return OPTIMIZE (sse2); > > +} > > diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c > > index 651b32908e..2d811a550b 100644 > > --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c > > +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c > > @@ -52,6 +52,11 @@ __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)), > > + __memchr_evex_rtm) > > IFUNC_IMPL_ADD (array, i, memchr, 1, __memchr_sse2)) > > > > /* Support sysdeps/x86_64/multiarch/memcmp.c. */ > > @@ -288,6 +293,11 @@ __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)), > > + __rawmemchr_evex_rtm) > > IFUNC_IMPL_ADD (array, i, rawmemchr, 1, __rawmemchr_sse2)) > > > > /* Support sysdeps/x86_64/multiarch/strlen.c. */ > > @@ -708,6 +718,11 @@ __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)), > > + __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/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 f3fdad4fda..4d0ed6d136 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 > > @@ -288,10 +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 > > - .p2align 4 > > + VZEROUPPER > > + > > L(last_4x_vec_or_less): > > /* Check if first VEC contained match. */ > > testl %eax, %eax > > @@ -338,73 +422,78 @@ 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..5a4131cb8f 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-evex.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..8133875405 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-evex.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..a346cd35a1 > > --- /dev/null > > +++ b/sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S > > @@ -0,0 +1,3 @@ > > +#define MEMCHR __wmemchr_evex_rtm > > +#define USE_AS_WMEMCHR 1 > > +#include "memchr-evex-rtm.S" > > diff --git a/sysdeps/x86_64/multiarch/wmemchr.c b/sysdeps/x86_64/multiarch/wmemchr.c > > index 393d520658..74509dcdd4 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-evex.h" > > > > libc_ifunc_redirected (__redirect_wmemchr, __wmemchr, IFUNC_SELECTOR ()); > > weak_alias (__wmemchr, wmemchr) > > -- > > 2.29.2 > > > > LGTM. > > Reviewed-by: H.J. Lu > > Thanks. > > H.J. I would like to backport this patch to release branches. Any comments or objections? --Sunil