From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi1-x230.google.com (mail-oi1-x230.google.com [IPv6:2607:f8b0:4864:20::230]) by sourceware.org (Postfix) with ESMTPS id D641E385781A for ; Sat, 17 Apr 2021 18:47:00 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org D641E385781A Received: by mail-oi1-x230.google.com with SMTP id v6so3587331oiv.3 for ; Sat, 17 Apr 2021 11:47:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=8vLnFwiR429t4X32qq9R0fIGoGmEu3nbkUBSpLKFhys=; b=Jr9Yr2dS4DxY0W14mvAiOuV6L5WAltop0e5wGvtDQDxEZtq0YxG7Cp5w+5tUoDEadb MolmriaWKVlOkvmIALQGvFPuDX6+qGJdL0kV78mYFidrXy2AKcLZkwIfk6jP33nhyQkM f+8LCgxRP6zDT5hRPE18lV5KdlIIlRcV4jkCFe01sAm9AHhUaNLZNcMUBcLEbwKVzzCW +yTxmi83b0Iqp5rwng8sh5ue1rZCYRZGSOAaWvW8KYDqmskqNcVITtIRudarxeAVivzL a2U12fpGTJABkI4FrmcAlcQPZeIweKkEy9Ik7kGOsmRQB+cs01fodjgM85CQ2n7iCATr +CRQ== X-Gm-Message-State: AOAM531G9FKJH3tN3Aydl7fQDiOu2mHLEZLt2oWN1l7oHjwP9I2Zu9nQ tTp93FnDbKLMiKIoPb5DsY26Esam+uGhi04fjupffXstyih3Og== X-Google-Smtp-Source: ABdhPJzppQVlYyRQsDue4cVCtZjyiQ6MuPwwDqCvziFkq6yBOtVW90cyO3sPPLEROaAG1+8vdHihMOQ9NYqSTvo5ezI= X-Received: by 2002:a05:6808:10c5:: with SMTP id s5mr10630545ois.58.1618685220023; Sat, 17 Apr 2021 11:47:00 -0700 (PDT) MIME-Version: 1.0 References: <20210417025215.874105-1-goldstein.w.n@gmail.com> <20210417025215.874105-2-goldstein.w.n@gmail.com> In-Reply-To: <20210417025215.874105-2-goldstein.w.n@gmail.com> From: "H.J. Lu" Date: Sat, 17 Apr 2021 11:46:23 -0700 Message-ID: Subject: Re: [PATCH v1 2/2] x86: Optimize strlen-avx2.S To: Noah Goldstein Cc: libc-alpha@sourceware.org, carlos@systemhalted.org Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3034.9 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: Sat, 17 Apr 2021 18:47:09 -0000 On Fri, Apr 16, 2021 at 7:53 PM Noah Goldstein wrote: > > No bug. This commit optimizes strlen-avx2.S. The optimizations are > mostly small things but they add up to roughly 10-30% performance > improvement for strlen. The results for strnlen are bit more > ambiguous. test-strlen, test-strnlen, test-wcslen, and test-wcsnlen > are all passing. > > Signed-off-by: Noah Goldstein > --- > sysdeps/x86_64/multiarch/strlen-avx2-rtm.S | 2 +- > sysdeps/x86_64/multiarch/strlen-avx2.S | 519 ++++++++++++--------- > 2 files changed, 311 insertions(+), 210 deletions(-) > > diff --git a/sysdeps/x86_64/multiarch/strlen-avx2-rtm.S b/sysdeps/x86_64/multiarch/strlen-avx2-rtm.S > index 75b4b7612c..50d40da0fb 100644 > --- a/sysdeps/x86_64/multiarch/strlen-avx2-rtm.S > +++ b/sysdeps/x86_64/multiarch/strlen-avx2-rtm.S > @@ -6,7 +6,7 @@ > ZERO_UPPER_VEC_REGISTERS_RETURN_XTEST > > #define VZEROUPPER_RETURN jmp L(return_vzeroupper) > - > +#define USE_IN_RTM 1 No need for this change. > #define SECTION(p) p##.avx.rtm > > #include "strlen-avx2.S" > diff --git a/sysdeps/x86_64/multiarch/strlen-avx2.S b/sysdeps/x86_64/multiarch/strlen-avx2.S > index 1caae9e6bc..7d76f4ed71 100644 > --- a/sysdeps/x86_64/multiarch/strlen-avx2.S > +++ b/sysdeps/x86_64/multiarch/strlen-avx2.S > @@ -27,9 +27,11 @@ > # ifdef USE_AS_WCSLEN > # define VPCMPEQ vpcmpeqd > # define VPMINU vpminud > +# define CHAR_SIZE 4 > # else > # define VPCMPEQ vpcmpeqb > # define VPMINU vpminub > +# define CHAR_SIZE 1 > # endif > > # ifndef VZEROUPPER > @@ -41,349 +43,448 @@ > # endif > > # define VEC_SIZE 32 > +# define PAGE_SIZE 4096 > > .section SECTION(.text),"ax",@progbits > ENTRY (STRLEN) > # ifdef USE_AS_STRNLEN > - /* Check for zero length. */ > + /* Check zero length. */ > test %RSI_LP, %RSI_LP > jz L(zero) > + mov %RSI_LP, %R8_LP Please add a comment to explain this change. > # ifdef USE_AS_WCSLEN > shl $2, %RSI_LP > # elif defined __ILP32__ > /* Clear the upper 32 bits. */ > movl %esi, %esi > # endif > - mov %RSI_LP, %R8_LP > # endif > - movl %edi, %ecx > + movl %edi, %eax > movq %rdi, %rdx > + sall $20, %eax Please add a comment to explain this change. > vpxor %xmm0, %xmm0, %xmm0 > - > /* 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) > + cmpl $((PAGE_SIZE - VEC_SIZE) << 20), %eax Please add a comment to explain this change and add comments to all changes which are 100% obvious. > + ja L(cross_page_boundary) > > /* Check the first VEC_SIZE bytes. */ > - VPCMPEQ (%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > - testl %eax, %eax > - > + VPCMPEQ (%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > # ifdef USE_AS_STRNLEN > - jnz L(first_vec_x0_check) > - /* Adjust length and check the end of data. */ > - subq $VEC_SIZE, %rsi > - jbe L(max) > -# else > - jnz L(first_vec_x0) > + /* If length < VEC_SIZE handle special. */ > + cmpq $VEC_SIZE, %rsi > + 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 > +# ifdef USE_AS_WCSLEN > + shrl $2, %eax > +# endif > + VZEROUPPER_RETURN > > # ifdef USE_AS_STRNLEN > - /* Adjust length. */ > - addq %rcx, %rsi > +L(zero): > + xorl %eax, %eax > + ret > > - subq $(VEC_SIZE * 4), %rsi > - jbe L(last_4x_vec_or_less) > + .p2align 4 > +L(first_vec_x0): > + /* Select min of length and position of first null. */ > + btsq %rsi, %rax > + tzcntl %eax, %eax > +# ifdef USE_AS_WCSLEN > + shrl $2, %eax > +# endif > + VZEROUPPER_RETURN > # 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 > - vpmovmskb %ymm1, %eax > - /* Remove the leading bytes. */ > - sarl %cl, %eax > - testl %eax, %eax > - jz L(aligned_more) > +L(first_vec_x1): > tzcntl %eax, %eax > + /* Safe to use 32 bit instructions as these are only called for > + size = [1, 159]. */ > # ifdef USE_AS_STRNLEN > - /* Check the end of data. */ > - cmpq %rax, %rsi > - jbe L(max) > + /* Use ecx which was computed earlier to compute correct value. > + */ > + subl $(VEC_SIZE * 4 + 1), %ecx > + addl %ecx, %eax > +# else > + subl %edx, %edi > + incl %edi > + addl %edi, %eax > # endif > - addq %rdi, %rax > - addq %rcx, %rax > - subq %rdx, %rax > # ifdef USE_AS_WCSLEN > - shrq $2, %rax > + shrl $2, %eax > # endif > -L(return_vzeroupper): > - ZERO_UPPER_VEC_REGISTERS_RETURN > + VZEROUPPER_RETURN > > .p2align 4 > -L(aligned_more): > +L(first_vec_x2): > + tzcntl %eax, %eax > + /* Safe to use 32 bit instructions as these are only called for > + size = [1, 159]. */ > # ifdef USE_AS_STRNLEN > - /* "rcx" is less than VEC_SIZE. 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 > - > - /* Check the end of data. */ > - subq %rcx, %rsi > - jbe L(max) > + /* Use ecx which was computed earlier to compute correct value. > + */ > + subl $(VEC_SIZE * 3 + 1), %ecx > + addl %ecx, %eax > +# else > + subl %edx, %edi > + addl $(VEC_SIZE + 1), %edi > + addl %edi, %eax > # endif > +# ifdef USE_AS_WCSLEN > + shrl $2, %eax > +# endif > + VZEROUPPER_RETURN > > - addq $VEC_SIZE, %rdi > + .p2align 4 > +L(first_vec_x3): > + tzcntl %eax, %eax > + /* Safe to use 32 bit instructions as these are only called for > + size = [1, 159]. */ > +# ifdef USE_AS_STRNLEN > + /* Use ecx which was computed earlier to compute correct value. > + */ > + subl $(VEC_SIZE * 2 + 1), %ecx > + addl %ecx, %eax > +# else > + subl %edx, %edi > + addl $(VEC_SIZE * 2 + 1), %edi > + addl %edi, %eax > +# endif > +# ifdef USE_AS_WCSLEN > + shrl $2, %eax > +# endif > + VZEROUPPER_RETURN > > + .p2align 4 > +L(first_vec_x4): > + tzcntl %eax, %eax > + /* Safe to use 32 bit instructions as these are only called for > + size = [1, 159]. */ > # ifdef USE_AS_STRNLEN > - subq $(VEC_SIZE * 4), %rsi > - jbe L(last_4x_vec_or_less) > + /* Use ecx which was computed earlier to compute correct value. > + */ > + subl $(VEC_SIZE + 1), %ecx > + addl %ecx, %eax > +# else > + subl %edx, %edi > + addl $(VEC_SIZE * 3 + 1), %edi > + addl %edi, %eax > # endif > +# ifdef USE_AS_WCSLEN > + shrl $2, %eax > +# endif > + VZEROUPPER_RETURN > > -L(more_4x_vec): > + .p2align 5 > +L(aligned_more): > + /* Align data to VEC_SIZE - 1. */ > + orq $(VEC_SIZE - 1), %rdi > +L(cross_page_continue): > /* 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) > - > - VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > +# ifdef USE_AS_STRNLEN > + /* + 1 because rdi is aligned to VEC_SIZE - 1. + CHAR_SIZE because > + it simplies the logic in last_4x_vec_or_less. */ > + leaq (VEC_SIZE * 4 + CHAR_SIZE + 1)(%rdi), %rcx > + subq %rdx, %rcx > +# endif > + /* Load first VEC regardless. */ > + VPCMPEQ 1(%rdi), %ymm0, %ymm1 > +# ifdef USE_AS_STRNLEN > + /* Adjust length. If near end handle specially. */ > + subq %rcx, %rsi > + jb L(last_4x_vec_or_less) > +# endif > + vpmovmskb %ymm1, %eax > testl %eax, %eax > jnz L(first_vec_x1) > > - VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > + 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 > - vpmovmskb %ymm1, %eax > + VPCMPEQ (VEC_SIZE * 2 + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > testl %eax, %eax > jnz L(first_vec_x3) > > - addq $(VEC_SIZE * 4), %rdi > - > -# ifdef USE_AS_STRNLEN > - subq $(VEC_SIZE * 4), %rsi > - 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 > + VPCMPEQ (VEC_SIZE * 3 + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > + testl %eax, %eax > + jnz L(first_vec_x4) > > + /* Align data to VEC_SIZE * 4 - 1. */ > # ifdef USE_AS_STRNLEN > - /* Adjust length. */ > + /* Before adjusting length check if at last VEC_SIZE * 4. */ > + cmpq $(VEC_SIZE * 4 - 1), %rsi > + jbe L(last_4x_vec_or_less_load) > + incq %rdi > + movl %edi, %ecx > + orq $(VEC_SIZE * 4 - 1), %rdi > + andl $(VEC_SIZE * 4 - 1), %ecx > + /* Readjust length. */ > addq %rcx, %rsi > +# else > + 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. */ > - vmovdqa (%rdi), %ymm1 > - vmovdqa VEC_SIZE(%rdi), %ymm2 > - vmovdqa (VEC_SIZE * 2)(%rdi), %ymm3 > - vmovdqa (VEC_SIZE * 3)(%rdi), %ymm4 > - VPMINU %ymm1, %ymm2, %ymm5 > - VPMINU %ymm3, %ymm4, %ymm6 > - VPMINU %ymm5, %ymm6, %ymm5 > - > - VPCMPEQ %ymm5, %ymm0, %ymm5 > - vpmovmskb %ymm5, %eax > - testl %eax, %eax > - jnz L(4x_vec_end) > - > - addq $(VEC_SIZE * 4), %rdi > - > -# ifndef USE_AS_STRNLEN > - jmp L(loop_4x_vec) > -# else > +# ifdef USE_AS_STRNLEN > + /* Break if at end of length. */ > subq $(VEC_SIZE * 4), %rsi > - ja L(loop_4x_vec) > + jb L(last_4x_vec_or_less_cmpeq) > +# endif > + vmovdqa 1(%rdi), %ymm1 > + VPMINU (VEC_SIZE + 1)(%rdi), %ymm1, %ymm2 > + vmovdqa (VEC_SIZE * 2 + 1)(%rdi), %ymm3 > + VPMINU (VEC_SIZE * 3 + 1)(%rdi), %ymm3, %ymm4 > > -L(last_4x_vec_or_less): > - /* Less than 4 * VEC and aligned to VEC_SIZE. */ > - addl $(VEC_SIZE * 2), %esi > - jle L(last_2x_vec) > + VPMINU %ymm2, %ymm4, %ymm5 > + VPCMPEQ %ymm5, %ymm0, %ymm5 > + vpmovmskb %ymm5, %ecx > > - VPCMPEQ (%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > - testl %eax, %eax > - jnz L(first_vec_x0) > + subq $-(VEC_SIZE * 4), %rdi > + testl %ecx, %ecx > + jz L(loop_4x_vec) > > - VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > - testl %eax, %eax > - jnz L(first_vec_x1) > > - VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > + VPCMPEQ %ymm1, %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > + subq %rdx, %rdi > testl %eax, %eax > + jnz L(last_vec_return_x0) > > - jnz L(first_vec_x2_check) > - subl $VEC_SIZE, %esi > - jle L(max) > - > - VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > + VPCMPEQ %ymm2, %ymm0, %ymm2 > + vpmovmskb %ymm2, %eax > testl %eax, %eax > - > - jnz L(first_vec_x3_check) > - movq %r8, %rax > -# ifdef USE_AS_WCSLEN > + jnz L(last_vec_return_x1) > + > + /* Combine last 2 VEC. */ > + VPCMPEQ %ymm3, %ymm0, %ymm3 > + vpmovmskb %ymm3, %eax > + /* rcx has combined result from all 4 VEC. It will only be used if > + the first 3 other VEC all did not contain a match. */ > + salq $32, %rcx > + orq %rcx, %rax > + tzcntq %rax, %rax > + subq $(VEC_SIZE * 2 - 1), %rdi > + addq %rdi, %rax > +# ifdef USE_AS_WCSLEN > shrq $2, %rax > -# endif > +# endif > VZEROUPPER_RETURN > > + > +# ifdef USE_AS_STRNLEN > .p2align 4 > -L(last_2x_vec): > - addl $(VEC_SIZE * 2), %esi > - VPCMPEQ (%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > - testl %eax, %eax > +L(last_4x_vec_or_less_load): > + /* Depending on entry adjust rdi / prepare first VEC in ymm1. */ > + subq $-(VEC_SIZE * 4), %rdi > +L(last_4x_vec_or_less_cmpeq): > + VPCMPEQ 1(%rdi), %ymm0, %ymm1 > +L(last_4x_vec_or_less): > > - jnz L(first_vec_x0_check) > - subl $VEC_SIZE, %esi > - jle L(max) > + vpmovmskb %ymm1, %eax > + /* If remaining length > VEC_SIZE * 2. */ > + testl $(VEC_SIZE * 2), %esi > + jnz L(last_4x_vec) > > - VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > + /* length may have been negative or positive depending on where > + this was called from. This fixes that. */ > + andl $(VEC_SIZE * 4 - 1), %esi > testl %eax, %eax > - jnz L(first_vec_x1_check) > - movq %r8, %rax > -# ifdef USE_AS_WCSLEN > - shrq $2, %rax > -# endif > - VZEROUPPER_RETURN > + jnz L(last_vec_x1_check) > > - .p2align 4 > -L(first_vec_x0_check): > + subl $VEC_SIZE, %esi > + jb L(max) > + > + VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > tzcntl %eax, %eax > /* Check the end of data. */ > - cmpq %rax, %rsi > - jbe L(max) > + cmpl %eax, %esi > + jb L(max) > + subq %rdx, %rdi > + addl $(VEC_SIZE + 1), %eax > addq %rdi, %rax > - subq %rdx, %rax > # ifdef USE_AS_WCSLEN > shrq $2, %rax > # endif > VZEROUPPER_RETURN > +# endif > > .p2align 4 > -L(first_vec_x1_check): > +L(last_vec_return_x0): > tzcntl %eax, %eax > - /* Check the end of data. */ > - cmpq %rax, %rsi > - jbe L(max) > - addq $VEC_SIZE, %rax > + subq $(VEC_SIZE * 4 - 1), %rdi > addq %rdi, %rax > - subq %rdx, %rax > -# ifdef USE_AS_WCSLEN > +# ifdef USE_AS_WCSLEN > shrq $2, %rax > -# endif > +# endif > VZEROUPPER_RETURN > > .p2align 4 > -L(first_vec_x2_check): > +L(last_vec_return_x1): > tzcntl %eax, %eax > - /* Check the end of data. */ > - cmpq %rax, %rsi > - jbe L(max) > - addq $(VEC_SIZE * 2), %rax > + subq $(VEC_SIZE * 3 - 1), %rdi > addq %rdi, %rax > - subq %rdx, %rax > -# ifdef USE_AS_WCSLEN > +# ifdef USE_AS_WCSLEN > shrq $2, %rax > -# endif > +# endif > VZEROUPPER_RETURN > > +# ifdef USE_AS_STRNLEN > .p2align 4 > -L(first_vec_x3_check): > +L(last_vec_x1_check): > + > tzcntl %eax, %eax > /* Check the end of data. */ > - cmpq %rax, %rsi > - jbe L(max) > - addq $(VEC_SIZE * 3), %rax > + cmpl %eax, %esi > + jb L(max) > + subq %rdx, %rdi > + incl %eax > addq %rdi, %rax > - subq %rdx, %rax > # ifdef USE_AS_WCSLEN > shrq $2, %rax > # endif > VZEROUPPER_RETURN > > - .p2align 4 > L(max): > movq %r8, %rax > + VZEROUPPER_RETURN > + > + .p2align 4 > +L(last_4x_vec): > + /* Test first 2x VEC normally. */ > + testl %eax, %eax > + jnz L(last_vec_x1) > + > + VPCMPEQ (VEC_SIZE + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > + testl %eax, %eax > + jnz L(last_vec_x2) > + > + /* Normalize length. */ > + andl $(VEC_SIZE * 4 - 1), %esi > + VPCMPEQ (VEC_SIZE * 2 + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > + testl %eax, %eax > + jnz L(last_vec_x3) > + > + subl $(VEC_SIZE * 3), %esi > + jb L(max) > + > + VPCMPEQ (VEC_SIZE * 3 + 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > + tzcntl %eax, %eax > + /* Check the end of data. */ > + cmpl %eax, %esi > + jb L(max) > + subq %rdx, %rdi > + addl $(VEC_SIZE * 3 + 1), %eax > + addq %rdi, %rax > # ifdef USE_AS_WCSLEN > shrq $2, %rax > # endif > VZEROUPPER_RETURN > > - .p2align 4 > -L(zero): > - xorl %eax, %eax > - ret > -# endif > > .p2align 4 > -L(first_vec_x0): > +L(last_vec_x1): > + /* essentially duplicates of first_vec_x1 but use 64 bit > + instructions. */ > tzcntl %eax, %eax > + subq %rdx, %rdi > + incl %eax > addq %rdi, %rax > - subq %rdx, %rax > -# ifdef USE_AS_WCSLEN > +# ifdef USE_AS_WCSLEN > shrq $2, %rax > -# endif > +# endif > VZEROUPPER_RETURN > > .p2align 4 > -L(first_vec_x1): > +L(last_vec_x2): > + /* essentially duplicates of first_vec_x1 but use 64 bit > + instructions. */ > tzcntl %eax, %eax > - addq $VEC_SIZE, %rax > + subq %rdx, %rdi > + addl $(VEC_SIZE + 1), %eax > addq %rdi, %rax > - subq %rdx, %rax > -# ifdef USE_AS_WCSLEN > +# ifdef USE_AS_WCSLEN > shrq $2, %rax > -# endif > +# endif > VZEROUPPER_RETURN > > .p2align 4 > -L(first_vec_x2): > +L(last_vec_x3): > tzcntl %eax, %eax > - addq $(VEC_SIZE * 2), %rax > + subl $(VEC_SIZE * 2), %esi > + /* Check the end of data. */ > + cmpl %eax, %esi > + jb L(max_end) > + subq %rdx, %rdi > + addl $(VEC_SIZE * 2 + 1), %eax > addq %rdi, %rax > - subq %rdx, %rax > -# ifdef USE_AS_WCSLEN > +# ifdef USE_AS_WCSLEN > shrq $2, %rax > -# endif > +# endif > + VZEROUPPER_RETURN > +L(max_end): > + movq %r8, %rax > VZEROUPPER_RETURN > +# endif > > + /* Cold case for crossing page with first load. */ > .p2align 4 > -L(4x_vec_end): > - VPCMPEQ %ymm1, %ymm0, %ymm1 > - vpmovmskb %ymm1, %eax > - testl %eax, %eax > - jnz L(first_vec_x0) > - VPCMPEQ %ymm2, %ymm0, %ymm2 > - vpmovmskb %ymm2, %eax > +L(cross_page_boundary): > + /* Align data to VEC_SIZE - 1. */ > + orq $(VEC_SIZE - 1), %rdi > + VPCMPEQ -(VEC_SIZE - 1)(%rdi), %ymm0, %ymm1 > + vpmovmskb %ymm1, %eax > + /* Remove the leading bytes. */ > + sarxl %edx, %eax, %eax > +# ifdef USE_AS_STRNLEN > testl %eax, %eax > - jnz L(first_vec_x1) > - VPCMPEQ %ymm3, %ymm0, %ymm3 > - vpmovmskb %ymm3, %eax > + jnz L(cross_page_less_vec) > + leaq 1(%rdi), %rcx > + subq %rdx, %rcx > + /* Check length. */ > + cmpq %rsi, %rcx > + jb L(cross_page_continue) > + movq %r8, %rax > +# else > testl %eax, %eax > - jnz L(first_vec_x2) > - VPCMPEQ %ymm4, %ymm0, %ymm4 > - vpmovmskb %ymm4, %eax > -L(first_vec_x3): > + jz L(cross_page_continue) > tzcntl %eax, %eax > - addq $(VEC_SIZE * 3), %rax > - addq %rdi, %rax > - subq %rdx, %rax > -# ifdef USE_AS_WCSLEN > - shrq $2, %rax > +# ifdef USE_AS_WCSLEN > + shrl $2, %eax > +# endif > # endif > +# ifdef USE_IN_RTM Remove this. > +L(return_vzeroupper): > + ZERO_UPPER_VEC_REGISTERS_RETURN > +# else > + VZEROUPPER_RETURN > +# endif Remove the 3 lines above. > + > +# ifdef USE_AS_STRNLEN > + .p2align 4 > +L(cross_page_less_vec): > + tzcntl %eax, %eax > + cmpq %rax, %rsi > + cmovb %esi, %eax > +# ifdef USE_AS_WCSLEN > + shrl $2, %eax > +# endif > VZEROUPPER_RETURN > +# endif > > END (STRLEN) > #endif > -- > 2.29.2 > Thanks. -- H.J.