From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-x42f.google.com (mail-pf1-x42f.google.com [IPv6:2607:f8b0:4864:20::42f]) by sourceware.org (Postfix) with ESMTPS id 65527393C846 for ; Mon, 3 May 2021 18:50:54 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 65527393C846 Received: by mail-pf1-x42f.google.com with SMTP id v191so4839126pfc.8 for ; Mon, 03 May 2021 11:50:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=jILtzDDI4NQYfTjLWR7LL30yNr9brl+Dcy22qyfOVKQ=; b=HhzGAT6fpI1UCS+yrstS47pyWjnsTL5UUwyh9zcFhkj0VG8uzxmOHfgEZ9rZP5zIwo DjU+g02BGWGZUUJqERIO10e9GsMOUWZNnr+a7zhAdQVaZ2o1yahxXaTZhDnKICGZNZk+ 2ZovKqZj/EFaICiV85cbsFFDXEs8g+m43dkH9N2iHSqWWfpONSV47jHx8E/oR1B8Dnpz irS1WeihURdhwCmlWcqFxesCz9rLJJxzUhBINGKvz/2eMLhYt1qjCtE8fNLUF6XtVurz LExMi9n7UWBjeyOAjhozrtMo2SUGZBxOXlJyrcZXtLSniw0QbutGiF43KJH0y+0EYP8j MKPg== X-Gm-Message-State: AOAM532Akw7GiCyNiYgSHxCgjcdRnafiA62icY7lPTsnx2ovg2ZBpt8F tnlB56xmtrB6q/WBnnxgIJ3pQDpRLwKHEQ== X-Google-Smtp-Source: ABdhPJyiE4zQL6s2zi+FTzjgtkdzzDlbKRgwXjW0mUHAkbr8zkikIl1+aw1l/d8LyjuAlzUBUewcjQ== X-Received: by 2002:a17:90a:4a95:: with SMTP id f21mr23041828pjh.180.1620067853287; Mon, 03 May 2021 11:50:53 -0700 (PDT) Received: from gnu-cfl-2.localdomain ([172.58.35.177]) by smtp.gmail.com with ESMTPSA id g13sm8253142pfi.18.2021.05.03.11.50.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 May 2021 11:50:52 -0700 (PDT) Received: by gnu-cfl-2.localdomain (Postfix, from userid 1000) id B364FC0304; Mon, 3 May 2021 11:50:50 -0700 (PDT) Date: Mon, 3 May 2021 11:50:50 -0700 From: "H.J. Lu" To: Noah Goldstein Cc: libc-alpha@sourceware.org, carlos@systemhalted.org, hjl.tools@gmail.com Subject: Re: [PATCH v1 2/3] x86: Optimize memchr-avx2.S Message-ID: References: <20210503084435.160548-1-goldstein.w.n@gmail.com> <20210503084435.160548-2-goldstein.w.n@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210503084435.160548-2-goldstein.w.n@gmail.com> X-Spam-Status: No, score=-3035.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 03 May 2021 18:50:56 -0000 On Mon, May 03, 2021 at 04:44:36AM -0400, Noah Goldstein wrote: > No bug. This commit optimizes memchr-avx2.S. The optimizations include > replacing some branches with cmovcc, avoiding some branches entirely > in the less_4x_vec case, making the page cross logic less strict, > asaving a few instructions the in loop return loop. test-memchr, > test-rawmemchr, and test-wmemchr are all passing. > > Signed-off-by: Noah Goldstein > --- > sysdeps/x86_64/multiarch/memchr-avx2.S | 446 +++++++++++++++---------- > 1 file changed, 262 insertions(+), 184 deletions(-) > > diff --git a/sysdeps/x86_64/multiarch/memchr-avx2.S b/sysdeps/x86_64/multiarch/memchr-avx2.S > index 1fcb1c350f..8368fcd1e1 100644 > --- a/sysdeps/x86_64/multiarch/memchr-avx2.S > +++ b/sysdeps/x86_64/multiarch/memchr-avx2.S > @@ -26,8 +26,22 @@ > > # ifdef USE_AS_WMEMCHR > # define VPCMPEQ vpcmpeqd > +# define VPBROADCAST vpbroadcastd > +# define CHAR_SIZE 4 > # else > # define VPCMPEQ vpcmpeqb > +# define VPBROADCAST vpbroadcastb > +# define CHAR_SIZE 1 > +# endif > + > +# ifdef USE_AS_RAWMEMCHR > +# define ERAW_PTR_REG ecx > +# define RRAW_PTR_REG rcx > +# define ALGN_PTR_REG rdi > +# else > +# define ERAW_PTR_REG edi > +# define RRAW_PTR_REG rdi > +# define ALGN_PTR_REG rcx > # endif > > # ifndef VZEROUPPER > @@ -39,303 +53,367 @@ > # endif > > # define VEC_SIZE 32 > +# define PAGE_SIZE 4096 > + Remove the extra line here. > > .section SECTION(.text),"ax",@progbits > -ENTRY (MEMCHR) > +ENTRY(MEMCHR) No need for this change. > # ifndef USE_AS_RAWMEMCHR > /* Check for zero length. */ > test %RDX_LP, %RDX_LP > jz L(null) > # endif > - movl %edi, %ecx > - /* Broadcast CHAR to YMM0. */ > - vmovd %esi, %xmm0 > # ifdef USE_AS_WMEMCHR > shl $2, %RDX_LP > - vpbroadcastd %xmm0, %ymm0 > # else > # ifdef __ILP32__ > /* Clear the upper 32 bits. */ > movl %edx, %edx > # endif > - vpbroadcastb %xmm0, %ymm0 > # endif > - /* Check if we may cross page boundary with one vector load. */ > - andl $(2 * VEC_SIZE - 1), %ecx > - cmpl $VEC_SIZE, %ecx > - ja L(cros_page_boundary) > + /* Broadcast CHAR to YMMMATCH. */ > + vmovd %esi, %xmm0 > + VPBROADCAST %xmm0, %ymm0 > + /* Check if we may cross page boundary with one > + vector load. */ > + movl %edi, %eax > + andl $(PAGE_SIZE - 1), %eax > + cmpl $(PAGE_SIZE - VEC_SIZE), %eax > + ja L(cross_page_boundary) > > /* Check the first VEC_SIZE bytes. */ > - VPCMPEQ (%rdi), %ymm0, %ymm1 > + VPCMPEQ (%rdi), %ymm0, %ymm1 > vpmovmskb %ymm1, %eax > - testl %eax, %eax > - > # ifndef USE_AS_RAWMEMCHR > - jnz L(first_vec_x0_check) > - /* Adjust length and check the end of data. */ > - subq $VEC_SIZE, %rdx > - jbe L(zero) > -# else > - jnz L(first_vec_x0) > + /* If length < CHAR_PER_VEC handle special. */ > + cmpq $VEC_SIZE, %rdx > + jbe L(first_vec_x0) > # endif > - > - /* Align data for aligned loads in the loop. */ > - addq $VEC_SIZE, %rdi > - andl $(VEC_SIZE - 1), %ecx > - andq $-VEC_SIZE, %rdi > + testl %eax, %eax > + jz L(aligned_more) > + tzcntl %eax, %eax > + addq %rdi, %rax > + VZEROUPPER_RETURN > > # ifndef USE_AS_RAWMEMCHR > - /* Adjust length. */ > - addq %rcx, %rdx > - > - subq $(VEC_SIZE * 4), %rdx > - jbe L(last_4x_vec_or_less) > + .p2align 5 > +L(first_vec_x0): > + /* Check if first match was before length. */ > + tzcntl %eax, %eax > + xorl %ecx, %ecx > + cmpl %eax, %edx > + leaq (%rdi, %rax), %rax > + cmovle %rcx, %rax > + VZEROUPPER_RETURN > +L(null): > + xorl %eax, %eax > + ret > # endif > - jmp L(more_4x_vec) > - > .p2align 4 > -L(cros_page_boundary): > - andl $(VEC_SIZE - 1), %ecx > - andq $-VEC_SIZE, %rdi > - VPCMPEQ (%rdi), %ymm0, %ymm1 > +L(cross_page_boundary): > + /* Save pointer before aligning as its original > + value is necessary for computer return address if byte is > + found or adjusting length if it is not and this is Fit comments to 72 columns. > + memchr. */ > + movq %rdi, %rcx > + /* Align data to VEC_SIZE - 1. ALGN_PTR_REG is > + rcx for memchr and rdi for rawmemchr. */ > + orq $(VEC_SIZE - 1), %ALGN_PTR_REG > + VPCMPEQ -(VEC_SIZE - 1)(%ALGN_PTR_REG), %ymm0, %ymm1 > vpmovmskb %ymm1, %eax > +# ifndef USE_AS_RAWMEMCHR > + /* Calculate length until end of page (length > + checked for a match). */ > + leaq 1(%ALGN_PTR_REG), %rsi > + subq %RRAW_PTR_REG, %rsi > +# endif > /* Remove the leading bytes. */ > - sarl %cl, %eax > - testl %eax, %eax > - jz L(aligned_more) > - tzcntl %eax, %eax > + sarxl %ERAW_PTR_REG, %eax, %eax > # ifndef USE_AS_RAWMEMCHR > /* Check the end of data. */ > - cmpq %rax, %rdx > - jbe L(zero) > + cmpq %rsi, %rdx > + jbe L(first_vec_x0) > # endif > - addq %rdi, %rax > - addq %rcx, %rax > + testl %eax, %eax > + jz L(cross_page_continue) > + tzcntl %eax, %eax > + addq %RRAW_PTR_REG, %rax > L(return_vzeroupper): > ZERO_UPPER_VEC_REGISTERS_RETURN > > .p2align 4 > -L(aligned_more): > -# ifndef USE_AS_RAWMEMCHR > - /* Calculate "rdx + rcx - VEC_SIZE" with "rdx - (VEC_SIZE - rcx)" > - instead of "(rdx + rcx) - VEC_SIZE" to void possible addition > - overflow. */ > - negq %rcx > - addq $VEC_SIZE, %rcx > +L(first_vec_x1): > + tzcntl %eax, %eax > + incq %rdi > + addq %rdi, %rax > + VZEROUPPER_RETURN > > - /* Check the end of data. */ > - subq %rcx, %rdx > - jbe L(zero) > -# endif > + .p2align 4 > +L(first_vec_x2): > + tzcntl %eax, %eax > + addq $(VEC_SIZE + 1), %rdi > + addq %rdi, %rax > + VZEROUPPER_RETURN > > - addq $VEC_SIZE, %rdi > + .p2align 4 > +L(first_vec_x3): > + tzcntl %eax, %eax > + addq $(VEC_SIZE * 2 + 1), %rdi > + addq %rdi, %rax > + VZEROUPPER_RETURN > > -# ifndef USE_AS_RAWMEMCHR > - subq $(VEC_SIZE * 4), %rdx > - jbe L(last_4x_vec_or_less) > -# endif > > -L(more_4x_vec): > - /* Check the first 4 * VEC_SIZE. Only one VEC_SIZE at a time > - since data is only aligned to VEC_SIZE. */ > - VPCMPEQ (%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > - testl %eax, %eax > - jnz L(first_vec_x0) > + .p2align 4 > +L(first_vec_x4): > + tzcntl %eax, %eax > + addq $(VEC_SIZE * 3 + 1), %rdi > + addq %rdi, %rax > + VZEROUPPER_RETURN > > - VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1 > + .p2align 4 > +L(aligned_more): > + /* Check the first 4 * VEC_SIZE. Only one > + VEC_SIZE at a time since data is only aligned to > + VEC_SIZE. */ Fit comments to 72 columns. > + > +# ifndef USE_AS_RAWMEMCHR > +L(cross_page_continue): > + /* Align data to VEC_SIZE - 1. */ > + xorl %ecx, %ecx > + subl %edi, %ecx > + orq $(VEC_SIZE - 1), %rdi > + /* esi is for adjusting length to see if near the > + end. */ Fit comments to 72 columns. > + leal (VEC_SIZE * 4 + 1)(%rdi, %rcx), %esi > +# else > + orq $(VEC_SIZE - 1), %rdi > +L(cross_page_continue): > +# endif > + /* Load first VEC regardless. */ > + VPCMPEQ 1(%rdi), %ymm0, %ymm1 > vpmovmskb %ymm1, %eax > +# ifndef USE_AS_RAWMEMCHR > + /* Adjust length. If near end handle specially. > + */ Put the comments on one line. > + subq %rsi, %rdx > + jbe L(last_4x_vec_or_less) > +# endif > testl %eax, %eax > jnz L(first_vec_x1) > > - VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm0, %ymm1 > + VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1 > vpmovmskb %ymm1, %eax > testl %eax, %eax > jnz L(first_vec_x2) > > - VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm0, %ymm1 > + VPCMPEQ (VEC_SIZE * 2 + 1)(%rdi), %ymm0, %ymm1 > vpmovmskb %ymm1, %eax > testl %eax, %eax > jnz L(first_vec_x3) > > - addq $(VEC_SIZE * 4), %rdi > + VPCMPEQ (VEC_SIZE * 3 + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > + testl %eax, %eax > + jnz L(first_vec_x4) > > # ifndef USE_AS_RAWMEMCHR > + /* Check if at last VEC_SIZE * 4 length. */ > subq $(VEC_SIZE * 4), %rdx > - jbe L(last_4x_vec_or_less) > -# endif > - > - /* Align data to 4 * VEC_SIZE. */ > - movq %rdi, %rcx > - andl $(4 * VEC_SIZE - 1), %ecx > - andq $-(4 * VEC_SIZE), %rdi > - > -# ifndef USE_AS_RAWMEMCHR > - /* Adjust length. */ > + jbe L(last_4x_vec_or_less_cmpeq) > + /* Align data to VEC_SIZE * 4 - 1 for the loop > + and readjust length. */ > + incq %rdi > + movl %edi, %ecx > + orq $(VEC_SIZE * 4 - 1), %rdi > + andl $(VEC_SIZE * 4 - 1), %ecx > addq %rcx, %rdx > +# else > + /* Align data to VEC_SIZE * 4 - 1 for loop. */ > + incq %rdi > + orq $(VEC_SIZE * 4 - 1), %rdi > # endif > > + /* Compare 4 * VEC at a time forward. */ > .p2align 4 > L(loop_4x_vec): > - /* Compare 4 * VEC at a time forward. */ > - VPCMPEQ (%rdi), %ymm0, %ymm1 > - VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm2 > - VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm0, %ymm3 > - VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm0, %ymm4 > - > + VPCMPEQ 1(%rdi), %ymm0, %ymm1 > + VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm2 > + VPCMPEQ (VEC_SIZE * 2 + 1)(%rdi), %ymm0, %ymm3 > + VPCMPEQ (VEC_SIZE * 3 + 1)(%rdi), %ymm0, %ymm4 > vpor %ymm1, %ymm2, %ymm5 > vpor %ymm3, %ymm4, %ymm6 > vpor %ymm5, %ymm6, %ymm5 > > - vpmovmskb %ymm5, %eax > - testl %eax, %eax > - jnz L(4x_vec_end) > - > - addq $(VEC_SIZE * 4), %rdi > - > + vpmovmskb %ymm5, %ecx > # ifdef USE_AS_RAWMEMCHR > - jmp L(loop_4x_vec) > + subq $-(VEC_SIZE * 4), %rdi > + testl %ecx, %ecx > + jz L(loop_4x_vec) > # else > - subq $(VEC_SIZE * 4), %rdx > - ja L(loop_4x_vec) > + testl %ecx, %ecx > + jnz L(loop_4x_vec_end) > > -L(last_4x_vec_or_less): > - /* Less than 4 * VEC and aligned to VEC_SIZE. */ > - addl $(VEC_SIZE * 2), %edx > - jle L(last_2x_vec) > + subq $-(VEC_SIZE * 4), %rdi > > - VPCMPEQ (%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > - testl %eax, %eax > - jnz L(first_vec_x0) > + subq $(VEC_SIZE * 4), %rdx > + ja L(loop_4x_vec) > > - VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1 > + /* Fall through into less than 4 remaining > + vectors of length case. */ Fit comments to 72 columns. > + VPCMPEQ (VEC_SIZE * 0 + 1)(%rdi), %ymm0, %ymm1 > vpmovmskb %ymm1, %eax > + .p2align 4 > +L(last_4x_vec_or_less): > + /* Check if first VEC contained match. */ > testl %eax, %eax > - jnz L(first_vec_x1) > + jnz L(first_vec_x1_check) > > - VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > - testl %eax, %eax > + /* If remaining length > VEC_SIZE * 2. */ > + addl $(VEC_SIZE * 2), %edx > + jg L(last_4x_vec) > > - jnz L(first_vec_x2_check) > - subl $VEC_SIZE, %edx > - jle L(zero) > +L(last_2x_vec): > + /* If remaining length < VEC_SIZE. */ > + addl $VEC_SIZE, %edx > + jle L(zero_end) > > - VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm0, %ymm1 > + /* Check VEC2 and compare any match with > + remaining length. */ Fit comments to 72 columns. > + VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1 > vpmovmskb %ymm1, %eax > - testl %eax, %eax > - > - jnz L(first_vec_x3_check) > - xorl %eax, %eax > + tzcntl %eax, %eax > + cmpl %eax, %edx > + jbe L(set_zero_end) > + addq $(VEC_SIZE + 1), %rdi > + addq %rdi, %rax > +L(zero_end): > VZEROUPPER_RETURN > > .p2align 4 > -L(last_2x_vec): > - addl $(VEC_SIZE * 2), %edx > - VPCMPEQ (%rdi), %ymm0, %ymm1 > +L(loop_4x_vec_end): > +# endif > + /* rawmemchr will fall through into this if match > + was found in loop. */ Fit comments to 72 columns. > + > vpmovmskb %ymm1, %eax > testl %eax, %eax > + jnz L(last_vec_x1_return) > > - jnz L(first_vec_x0_check) > - subl $VEC_SIZE, %edx > - jle L(zero) > - > - VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > + vpmovmskb %ymm2, %eax > testl %eax, %eax > - jnz L(first_vec_x1_check) > - xorl %eax, %eax > - VZEROUPPER_RETURN > + jnz L(last_vec_x2_return) > > - .p2align 4 > -L(first_vec_x0_check): > - tzcntl %eax, %eax > - /* Check the end of data. */ > - cmpq %rax, %rdx > - jbe L(zero) > + vpmovmskb %ymm3, %eax > + /* Combine VEC3 matches (eax) with VEC4 matches > + (ecx). */ Fit comments to 72 columns. > + salq $32, %rcx > + orq %rcx, %rax > + tzcntq %rax, %rax > +# ifdef USE_AS_RAWMEMCHR > + subq $(VEC_SIZE * 2 - 1), %rdi > +# else > + subq $-(VEC_SIZE * 2 + 1), %rdi > +# endif > addq %rdi, %rax > VZEROUPPER_RETURN > +# ifndef USE_AS_RAWMEMCHR > > .p2align 4 > L(first_vec_x1_check): > tzcntl %eax, %eax > - /* Check the end of data. */ > - cmpq %rax, %rdx > - jbe L(zero) > - addq $VEC_SIZE, %rax > + /* Adjust length. */ > + subl $-(VEC_SIZE * 4), %edx > + /* Check if match within remaining length. */ > + cmpl %eax, %edx > + jbe L(set_zero_end) > + incq %rdi > addq %rdi, %rax > VZEROUPPER_RETURN > + .p2align 4 > +L(set_zero_end): > + xorl %eax, %eax > + VZEROUPPER_RETURN > +# endif > > .p2align 4 > -L(first_vec_x2_check): > +L(last_vec_x1_return): > tzcntl %eax, %eax > - /* Check the end of data. */ > - cmpq %rax, %rdx > - jbe L(zero) > - addq $(VEC_SIZE * 2), %rax > +# ifdef USE_AS_RAWMEMCHR > + subq $(VEC_SIZE * 4 - 1), %rdi > +# else > + incq %rdi > +# endif > addq %rdi, %rax > VZEROUPPER_RETURN > > .p2align 4 > -L(first_vec_x3_check): > +L(last_vec_x2_return): > tzcntl %eax, %eax > - /* Check the end of data. */ > - cmpq %rax, %rdx > - jbe L(zero) > - addq $(VEC_SIZE * 3), %rax > +# ifdef USE_AS_RAWMEMCHR > + subq $(VEC_SIZE * 3 - 1), %rdi > +# else > + subq $-(VEC_SIZE + 1), %rdi > +# endif > addq %rdi, %rax > VZEROUPPER_RETURN > > +# ifndef USE_AS_RAWMEMCHR > .p2align 4 > -L(zero): > - xorl %eax, %eax > - jmp L(return_vzeroupper) > +L(last_4x_vec_or_less_cmpeq): > + VPCMPEQ (VEC_SIZE * 4 + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > + subq $-(VEC_SIZE * 4), %rdi > + /* Check first VEC regardless. */ > + testl %eax, %eax > + jnz L(first_vec_x1_check) > > + /* If remaining length <= CHAR_PER_VEC * 2. */ > + addl $(VEC_SIZE * 2), %edx > + jle L(last_2x_vec) > .p2align 4 > -L(null): > - xorl %eax, %eax > - ret > -# endif > +L(last_4x_vec): > + VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > + testl %eax, %eax > + jnz L(last_vec_x2_return) > > - .p2align 4 > -L(first_vec_x0): > - tzcntl %eax, %eax > - addq %rdi, %rax > - VZEROUPPER_RETURN > + VPCMPEQ (VEC_SIZE * 2 + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > > - .p2align 4 > -L(first_vec_x1): > - tzcntl %eax, %eax > - addq $VEC_SIZE, %rax > - addq %rdi, %rax > - VZEROUPPER_RETURN > + /* Create mask for possible matches within > + remaining length. */ Fit comments to 72 columns. > + movq $-1, %rcx > + bzhiq %rdx, %rcx, %rcx > > - .p2align 4 > -L(first_vec_x2): > + /* Test matches in data against length match. */ > + andl %ecx, %eax > + jnz L(last_vec_x3) > + > + /* if remaining length <= VEC_SIZE * 3 (Note this > + is after remaining length was found to be > VEC_SIZE * 2. Fit comments to 72 columns. > + */ > + subl $VEC_SIZE, %edx > + jbe L(zero_end2) > + > + VPCMPEQ (VEC_SIZE * 3 + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > + /* Shift remaining length mask for last VEC. */ > + shrq $32, %rcx > + andl %ecx, %eax > + jz L(zero_end2) > tzcntl %eax, %eax > - addq $(VEC_SIZE * 2), %rax > + addq $(VEC_SIZE * 3 + 1), %rdi > addq %rdi, %rax > +L(zero_end2): > VZEROUPPER_RETURN > > .p2align 4 > -L(4x_vec_end): > - vpmovmskb %ymm1, %eax > - testl %eax, %eax > - jnz L(first_vec_x0) > - vpmovmskb %ymm2, %eax > - testl %eax, %eax > - jnz L(first_vec_x1) > - vpmovmskb %ymm3, %eax > - testl %eax, %eax > - jnz L(first_vec_x2) > - vpmovmskb %ymm4, %eax > - testl %eax, %eax > -L(first_vec_x3): > +L(last_vec_x3): > tzcntl %eax, %eax > - addq $(VEC_SIZE * 3), %rax > + subq $-(VEC_SIZE * 2 + 1), %rdi > addq %rdi, %rax > VZEROUPPER_RETURN > +# endif > > -END (MEMCHR) > +END(MEMCHR) No need for this change. > #endif > -- > 2.29.2 > Thanks. H.J.