From: "H.J. Lu" <hjl.tools@gmail.com>
To: Noah Goldstein <goldstein.w.n@gmail.com>
Cc: GNU C Library <libc-alpha@sourceware.org>,
"Carlos O'Donell" <carlos@systemhalted.org>
Subject: Re: [PATCH v3 2/3] x86: Remove memcmp-sse4.S
Date: Fri, 15 Apr 2022 10:32:19 -0700 [thread overview]
Message-ID: <CAMe9rOr2Cr4FRJDY2p7J3HVtDt4VmQAkt-MPtETj-+cCfvUJ0w@mail.gmail.com> (raw)
In-Reply-To: <20220415172801.1525674-2-goldstein.w.n@gmail.com>
On Fri, Apr 15, 2022 at 10:28 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> Code didn't actually use any sse4 instructions since `ptest` was
> removed in:
>
> commit 2f9062d7171850451e6044ef78d91ff8c017b9c0
> Author: Noah Goldstein <goldstein.w.n@gmail.com>
> Date: Wed Nov 10 16:18:56 2021 -0600
>
> x86: Shrink memcmp-sse4.S code size
>
> The new memcmp-sse2 implementation is also faster.
>
> geometric_mean(N=20) of page cross cases SSE2 / SSE4: 0.905
>
> Note there are two regressions prefering SSE2 for Size = 1 and Size =
preferring
LGTM with the commit log typo fix.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Thanks.
> 65.
>
> Size = 1:
> size, align0, align1, ret, New Time/Old Time
> 1, 1, 1, 0, 1.2
> 1, 1, 1, 1, 1.197
> 1, 1, 1, -1, 1.2
>
> This is intentional. Size == 1 is significantly less hot based on
> profiles of GCC11 and Python3 than sizes [4, 8] (which is made
> hotter).
>
> Python3 Size = 1 -> 13.64%
> Python3 Size = [4, 8] -> 60.92%
>
> GCC11 Size = 1 -> 1.29%
> GCC11 Size = [4, 8] -> 33.86%
>
> size, align0, align1, ret, New Time/Old Time
> 4, 4, 4, 0, 0.622
> 4, 4, 4, 1, 0.797
> 4, 4, 4, -1, 0.805
> 5, 5, 5, 0, 0.623
> 5, 5, 5, 1, 0.777
> 5, 5, 5, -1, 0.802
> 6, 6, 6, 0, 0.625
> 6, 6, 6, 1, 0.813
> 6, 6, 6, -1, 0.788
> 7, 7, 7, 0, 0.625
> 7, 7, 7, 1, 0.799
> 7, 7, 7, -1, 0.795
> 8, 8, 8, 0, 0.625
> 8, 8, 8, 1, 0.848
> 8, 8, 8, -1, 0.914
> 9, 9, 9, 0, 0.625
>
> Size = 65:
> size, align0, align1, ret, New Time/Old Time
> 65, 0, 0, 0, 1.103
> 65, 0, 0, 1, 1.216
> 65, 0, 0, -1, 1.227
> 65, 65, 0, 0, 1.091
> 65, 0, 65, 1, 1.19
> 65, 65, 65, -1, 1.215
>
> This is because A) the checks in range [65, 96] are now unrolled 2x
> and B) because smaller values <= 16 are now given a hotter path. By
> contrast the SSE4 version has a branch for Size = 80. The unrolled
> version has get better performance for returns which need both
> comparisons.
>
> size, align0, align1, ret, New Time/Old Time
> 128, 4, 8, 0, 0.858
> 128, 4, 8, 1, 0.879
> 128, 4, 8, -1, 0.888
>
> As well, out of microbenchmark environments that are not full
> predictable the branch will have a real-cost.
> ---
> sysdeps/x86_64/multiarch/Makefile | 2 -
> sysdeps/x86_64/multiarch/ifunc-impl-list.c | 4 -
> sysdeps/x86_64/multiarch/ifunc-memcmp.h | 4 -
> sysdeps/x86_64/multiarch/memcmp-sse4.S | 803 ---------------------
> 4 files changed, 813 deletions(-)
> delete mode 100644 sysdeps/x86_64/multiarch/memcmp-sse4.S
>
> diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
> index b573966966..0400ea332b 100644
> --- a/sysdeps/x86_64/multiarch/Makefile
> +++ b/sysdeps/x86_64/multiarch/Makefile
> @@ -11,7 +11,6 @@ sysdep_routines += \
> memcmp-avx2-movbe-rtm \
> memcmp-evex-movbe \
> memcmp-sse2 \
> - memcmp-sse4 \
> memcmpeq-avx2 \
> memcmpeq-avx2-rtm \
> memcmpeq-evex \
> @@ -164,7 +163,6 @@ sysdep_routines += \
> wmemcmp-avx2-movbe-rtm \
> wmemcmp-evex-movbe \
> wmemcmp-sse2 \
> - wmemcmp-sse4 \
> # sysdep_routines
> endif
>
> diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> index c6008a73ed..a8afcf81bb 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> @@ -96,8 +96,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> && CPU_FEATURE_USABLE (BMI2)
> && CPU_FEATURE_USABLE (MOVBE)),
> __memcmp_evex_movbe)
> - IFUNC_IMPL_ADD (array, i, memcmp, CPU_FEATURE_USABLE (SSE4_1),
> - __memcmp_sse4_1)
> IFUNC_IMPL_ADD (array, i, memcmp, 1, __memcmp_sse2))
>
> #ifdef SHARED
> @@ -809,8 +807,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> && CPU_FEATURE_USABLE (BMI2)
> && CPU_FEATURE_USABLE (MOVBE)),
> __wmemcmp_evex_movbe)
> - IFUNC_IMPL_ADD (array, i, wmemcmp, CPU_FEATURE_USABLE (SSE4_1),
> - __wmemcmp_sse4_1)
> IFUNC_IMPL_ADD (array, i, wmemcmp, 1, __wmemcmp_sse2))
>
> /* Support sysdeps/x86_64/multiarch/wmemset.c. */
> diff --git a/sysdeps/x86_64/multiarch/ifunc-memcmp.h b/sysdeps/x86_64/multiarch/ifunc-memcmp.h
> index 44759a3ad5..c743970fe3 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-memcmp.h
> +++ b/sysdeps/x86_64/multiarch/ifunc-memcmp.h
> @@ -20,7 +20,6 @@
> # include <init-arch.h>
>
> extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
> -extern __typeof (REDIRECT_NAME) OPTIMIZE (sse4_1) attribute_hidden;
> extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe) attribute_hidden;
> extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe_rtm) attribute_hidden;
> extern __typeof (REDIRECT_NAME) OPTIMIZE (evex_movbe) attribute_hidden;
> @@ -46,8 +45,5 @@ IFUNC_SELECTOR (void)
> return OPTIMIZE (avx2_movbe);
> }
>
> - if (CPU_FEATURE_USABLE_P (cpu_features, SSE4_1))
> - return OPTIMIZE (sse4_1);
> -
> return OPTIMIZE (sse2);
> }
> diff --git a/sysdeps/x86_64/multiarch/memcmp-sse4.S b/sysdeps/x86_64/multiarch/memcmp-sse4.S
> deleted file mode 100644
> index cd57c1e2c7..0000000000
> --- a/sysdeps/x86_64/multiarch/memcmp-sse4.S
> +++ /dev/null
> @@ -1,803 +0,0 @@
> -/* memcmp with SSE4.1, wmemcmp with SSE4.1
> - Copyright (C) 2010-2022 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/>. */
> -
> -#if IS_IN (libc)
> -
> -# include <sysdep.h>
> -
> -# ifndef MEMCMP
> -# define MEMCMP __memcmp_sse4_1
> -# endif
> -
> -#ifdef USE_AS_WMEMCMP
> -# define CMPEQ pcmpeqd
> -# define CHAR_SIZE 4
> -#else
> -# define CMPEQ pcmpeqb
> -# define CHAR_SIZE 1
> -#endif
> -
> -
> -/* Warning!
> - wmemcmp has to use SIGNED comparison for elements.
> - memcmp has to use UNSIGNED comparison for elemnts.
> -*/
> -
> - .section .text.sse4.1,"ax",@progbits
> -ENTRY (MEMCMP)
> -# ifdef USE_AS_WMEMCMP
> - shl $2, %RDX_LP
> -# elif defined __ILP32__
> - /* Clear the upper 32 bits. */
> - mov %edx, %edx
> -# endif
> - cmp $79, %RDX_LP
> - ja L(79bytesormore)
> -
> - cmp $CHAR_SIZE, %RDX_LP
> - jbe L(firstbyte)
> -
> - /* N in (CHAR_SIZE, 79) bytes. */
> - cmpl $32, %edx
> - ja L(more_32_bytes)
> -
> - cmpl $16, %edx
> - jae L(16_to_32_bytes)
> -
> -# ifndef USE_AS_WMEMCMP
> - cmpl $8, %edx
> - jae L(8_to_16_bytes)
> -
> - cmpl $4, %edx
> - jb L(2_to_3_bytes)
> -
> - movl (%rdi), %eax
> - movl (%rsi), %ecx
> -
> - bswap %eax
> - bswap %ecx
> -
> - shlq $32, %rax
> - shlq $32, %rcx
> -
> - movl -4(%rdi, %rdx), %edi
> - movl -4(%rsi, %rdx), %esi
> -
> - bswap %edi
> - bswap %esi
> -
> - orq %rdi, %rax
> - orq %rsi, %rcx
> - subq %rcx, %rax
> - cmovne %edx, %eax
> - sbbl %ecx, %ecx
> - orl %ecx, %eax
> - ret
> -
> - .p2align 4,, 8
> -L(2_to_3_bytes):
> - movzwl (%rdi), %eax
> - movzwl (%rsi), %ecx
> - shll $8, %eax
> - shll $8, %ecx
> - bswap %eax
> - bswap %ecx
> - movzbl -1(%rdi, %rdx), %edi
> - movzbl -1(%rsi, %rdx), %esi
> - orl %edi, %eax
> - orl %esi, %ecx
> - subl %ecx, %eax
> - ret
> -
> - .p2align 4,, 8
> -L(8_to_16_bytes):
> - movq (%rdi), %rax
> - movq (%rsi), %rcx
> -
> - bswap %rax
> - bswap %rcx
> -
> - subq %rcx, %rax
> - jne L(8_to_16_bytes_done)
> -
> - movq -8(%rdi, %rdx), %rax
> - movq -8(%rsi, %rdx), %rcx
> -
> - bswap %rax
> - bswap %rcx
> -
> - subq %rcx, %rax
> -
> -L(8_to_16_bytes_done):
> - cmovne %edx, %eax
> - sbbl %ecx, %ecx
> - orl %ecx, %eax
> - ret
> -# else
> - xorl %eax, %eax
> - movl (%rdi), %ecx
> - cmpl (%rsi), %ecx
> - jne L(8_to_16_bytes_done)
> - movl 4(%rdi), %ecx
> - cmpl 4(%rsi), %ecx
> - jne L(8_to_16_bytes_done)
> - movl -4(%rdi, %rdx), %ecx
> - cmpl -4(%rsi, %rdx), %ecx
> - jne L(8_to_16_bytes_done)
> - ret
> -# endif
> -
> - .p2align 4,, 3
> -L(ret_zero):
> - xorl %eax, %eax
> -L(zero):
> - ret
> -
> - .p2align 4,, 8
> -L(firstbyte):
> - jb L(ret_zero)
> -# ifdef USE_AS_WMEMCMP
> - xorl %eax, %eax
> - movl (%rdi), %ecx
> - cmpl (%rsi), %ecx
> - je L(zero)
> -L(8_to_16_bytes_done):
> - setg %al
> - leal -1(%rax, %rax), %eax
> -# else
> - movzbl (%rdi), %eax
> - movzbl (%rsi), %ecx
> - sub %ecx, %eax
> -# endif
> - ret
> -
> - .p2align 4
> -L(vec_return_begin_48):
> - addq $16, %rdi
> - addq $16, %rsi
> -L(vec_return_begin_32):
> - bsfl %eax, %eax
> -# ifdef USE_AS_WMEMCMP
> - movl 32(%rdi, %rax), %ecx
> - xorl %edx, %edx
> - cmpl 32(%rsi, %rax), %ecx
> - setg %dl
> - leal -1(%rdx, %rdx), %eax
> -# else
> - movzbl 32(%rsi, %rax), %ecx
> - movzbl 32(%rdi, %rax), %eax
> - subl %ecx, %eax
> -# endif
> - ret
> -
> - .p2align 4
> -L(vec_return_begin_16):
> - addq $16, %rdi
> - addq $16, %rsi
> -L(vec_return_begin):
> - bsfl %eax, %eax
> -# ifdef USE_AS_WMEMCMP
> - movl (%rdi, %rax), %ecx
> - xorl %edx, %edx
> - cmpl (%rsi, %rax), %ecx
> - setg %dl
> - leal -1(%rdx, %rdx), %eax
> -# else
> - movzbl (%rsi, %rax), %ecx
> - movzbl (%rdi, %rax), %eax
> - subl %ecx, %eax
> -# endif
> - ret
> -
> - .p2align 4
> -L(vec_return_end_16):
> - subl $16, %edx
> -L(vec_return_end):
> - bsfl %eax, %eax
> - addl %edx, %eax
> -# ifdef USE_AS_WMEMCMP
> - movl -16(%rdi, %rax), %ecx
> - xorl %edx, %edx
> - cmpl -16(%rsi, %rax), %ecx
> - setg %dl
> - leal -1(%rdx, %rdx), %eax
> -# else
> - movzbl -16(%rsi, %rax), %ecx
> - movzbl -16(%rdi, %rax), %eax
> - subl %ecx, %eax
> -# endif
> - ret
> -
> - .p2align 4,, 8
> -L(more_32_bytes):
> - movdqu (%rdi), %xmm0
> - movdqu (%rsi), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> - movdqu 16(%rdi), %xmm0
> - movdqu 16(%rsi), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_16)
> -
> - cmpl $64, %edx
> - jbe L(32_to_64_bytes)
> - movdqu 32(%rdi), %xmm0
> - movdqu 32(%rsi), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_32)
> -
> - .p2align 4,, 6
> -L(32_to_64_bytes):
> - movdqu -32(%rdi, %rdx), %xmm0
> - movdqu -32(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end_16)
> -
> - movdqu -16(%rdi, %rdx), %xmm0
> - movdqu -16(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end)
> - ret
> -
> - .p2align 4
> -L(16_to_32_bytes):
> - movdqu (%rdi), %xmm0
> - movdqu (%rsi), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> - movdqu -16(%rdi, %rdx), %xmm0
> - movdqu -16(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end)
> - ret
> -
> -
> - .p2align 4
> -L(79bytesormore):
> - movdqu (%rdi), %xmm0
> - movdqu (%rsi), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> -
> - mov %rsi, %rcx
> - and $-16, %rsi
> - add $16, %rsi
> - sub %rsi, %rcx
> -
> - sub %rcx, %rdi
> - add %rcx, %rdx
> - test $0xf, %rdi
> - jz L(2aligned)
> -
> - cmp $128, %rdx
> - ja L(128bytesormore)
> -
> - .p2align 4,, 6
> -L(less128bytes):
> - movdqu (%rdi), %xmm1
> - CMPEQ (%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> - movdqu 16(%rdi), %xmm1
> - CMPEQ 16(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_16)
> -
> - movdqu 32(%rdi), %xmm1
> - CMPEQ 32(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_32)
> -
> - movdqu 48(%rdi), %xmm1
> - CMPEQ 48(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_48)
> -
> - cmp $96, %rdx
> - jb L(32_to_64_bytes)
> -
> - addq $64, %rdi
> - addq $64, %rsi
> - subq $64, %rdx
> -
> - .p2align 4,, 6
> -L(last_64_bytes):
> - movdqu (%rdi), %xmm1
> - CMPEQ (%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> - movdqu 16(%rdi), %xmm1
> - CMPEQ 16(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_16)
> -
> - movdqu -32(%rdi, %rdx), %xmm0
> - movdqu -32(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end_16)
> -
> - movdqu -16(%rdi, %rdx), %xmm0
> - movdqu -16(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end)
> - ret
> -
> - .p2align 4
> -L(128bytesormore):
> - cmp $256, %rdx
> - ja L(unaligned_loop)
> -L(less256bytes):
> - movdqu (%rdi), %xmm1
> - CMPEQ (%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> - movdqu 16(%rdi), %xmm1
> - CMPEQ 16(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_16)
> -
> - movdqu 32(%rdi), %xmm1
> - CMPEQ 32(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_32)
> -
> - movdqu 48(%rdi), %xmm1
> - CMPEQ 48(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_48)
> -
> - addq $64, %rdi
> - addq $64, %rsi
> -
> - movdqu (%rdi), %xmm1
> - CMPEQ (%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> - movdqu 16(%rdi), %xmm1
> - CMPEQ 16(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_16)
> -
> - movdqu 32(%rdi), %xmm1
> - CMPEQ 32(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_32)
> -
> - movdqu 48(%rdi), %xmm1
> - CMPEQ 48(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_48)
> -
> - addq $-128, %rdx
> - subq $-64, %rsi
> - subq $-64, %rdi
> -
> - cmp $64, %rdx
> - ja L(less128bytes)
> -
> - cmp $32, %rdx
> - ja L(last_64_bytes)
> -
> - movdqu -32(%rdi, %rdx), %xmm0
> - movdqu -32(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end_16)
> -
> - movdqu -16(%rdi, %rdx), %xmm0
> - movdqu -16(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end)
> - ret
> -
> - .p2align 4
> -L(unaligned_loop):
> -# ifdef DATA_CACHE_SIZE_HALF
> - mov $DATA_CACHE_SIZE_HALF, %R8_LP
> -# else
> - mov __x86_data_cache_size_half(%rip), %R8_LP
> -# endif
> - movq %r8, %r9
> - addq %r8, %r8
> - addq %r9, %r8
> - cmpq %r8, %rdx
> - ja L(L2_L3_cache_unaligned)
> - sub $64, %rdx
> - .p2align 4
> -L(64bytesormore_loop):
> - movdqu (%rdi), %xmm0
> - movdqu 16(%rdi), %xmm1
> - movdqu 32(%rdi), %xmm2
> - movdqu 48(%rdi), %xmm3
> -
> - CMPEQ (%rsi), %xmm0
> - CMPEQ 16(%rsi), %xmm1
> - CMPEQ 32(%rsi), %xmm2
> - CMPEQ 48(%rsi), %xmm3
> -
> - pand %xmm0, %xmm1
> - pand %xmm2, %xmm3
> - pand %xmm1, %xmm3
> -
> - pmovmskb %xmm3, %eax
> - incw %ax
> - jnz L(64bytesormore_loop_end)
> -
> - add $64, %rsi
> - add $64, %rdi
> - sub $64, %rdx
> - ja L(64bytesormore_loop)
> -
> - .p2align 4,, 6
> -L(loop_tail):
> - addq %rdx, %rdi
> - movdqu (%rdi), %xmm0
> - movdqu 16(%rdi), %xmm1
> - movdqu 32(%rdi), %xmm2
> - movdqu 48(%rdi), %xmm3
> -
> - addq %rdx, %rsi
> - movdqu (%rsi), %xmm4
> - movdqu 16(%rsi), %xmm5
> - movdqu 32(%rsi), %xmm6
> - movdqu 48(%rsi), %xmm7
> -
> - CMPEQ %xmm4, %xmm0
> - CMPEQ %xmm5, %xmm1
> - CMPEQ %xmm6, %xmm2
> - CMPEQ %xmm7, %xmm3
> -
> - pand %xmm0, %xmm1
> - pand %xmm2, %xmm3
> - pand %xmm1, %xmm3
> -
> - pmovmskb %xmm3, %eax
> - incw %ax
> - jnz L(64bytesormore_loop_end)
> - ret
> -
> -L(L2_L3_cache_unaligned):
> - subq $64, %rdx
> - .p2align 4
> -L(L2_L3_unaligned_128bytes_loop):
> - prefetchnta 0x1c0(%rdi)
> - prefetchnta 0x1c0(%rsi)
> -
> - movdqu (%rdi), %xmm0
> - movdqu 16(%rdi), %xmm1
> - movdqu 32(%rdi), %xmm2
> - movdqu 48(%rdi), %xmm3
> -
> - CMPEQ (%rsi), %xmm0
> - CMPEQ 16(%rsi), %xmm1
> - CMPEQ 32(%rsi), %xmm2
> - CMPEQ 48(%rsi), %xmm3
> -
> - pand %xmm0, %xmm1
> - pand %xmm2, %xmm3
> - pand %xmm1, %xmm3
> -
> - pmovmskb %xmm3, %eax
> - incw %ax
> - jnz L(64bytesormore_loop_end)
> -
> - add $64, %rsi
> - add $64, %rdi
> - sub $64, %rdx
> - ja L(L2_L3_unaligned_128bytes_loop)
> - jmp L(loop_tail)
> -
> -
> - /* This case is for machines which are sensitive for unaligned
> - * instructions. */
> - .p2align 4
> -L(2aligned):
> - cmp $128, %rdx
> - ja L(128bytesormorein2aligned)
> -L(less128bytesin2aligned):
> - movdqa (%rdi), %xmm1
> - CMPEQ (%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> - movdqa 16(%rdi), %xmm1
> - CMPEQ 16(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_16)
> -
> - movdqa 32(%rdi), %xmm1
> - CMPEQ 32(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_32)
> -
> - movdqa 48(%rdi), %xmm1
> - CMPEQ 48(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_48)
> -
> - cmp $96, %rdx
> - jb L(32_to_64_bytes)
> -
> - addq $64, %rdi
> - addq $64, %rsi
> - subq $64, %rdx
> -
> - .p2align 4,, 6
> -L(aligned_last_64_bytes):
> - movdqa (%rdi), %xmm1
> - CMPEQ (%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> - movdqa 16(%rdi), %xmm1
> - CMPEQ 16(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_16)
> -
> - movdqu -32(%rdi, %rdx), %xmm0
> - movdqu -32(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end_16)
> -
> - movdqu -16(%rdi, %rdx), %xmm0
> - movdqu -16(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end)
> - ret
> -
> - .p2align 4
> -L(128bytesormorein2aligned):
> - cmp $256, %rdx
> - ja L(aligned_loop)
> -L(less256bytesin2alinged):
> - movdqa (%rdi), %xmm1
> - CMPEQ (%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> - movdqa 16(%rdi), %xmm1
> - CMPEQ 16(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_16)
> -
> - movdqa 32(%rdi), %xmm1
> - CMPEQ 32(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_32)
> -
> - movdqa 48(%rdi), %xmm1
> - CMPEQ 48(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_48)
> -
> - addq $64, %rdi
> - addq $64, %rsi
> -
> - movdqa (%rdi), %xmm1
> - CMPEQ (%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin)
> -
> - movdqa 16(%rdi), %xmm1
> - CMPEQ 16(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_16)
> -
> - movdqa 32(%rdi), %xmm1
> - CMPEQ 32(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_32)
> -
> - movdqa 48(%rdi), %xmm1
> - CMPEQ 48(%rsi), %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_begin_48)
> -
> - addq $-128, %rdx
> - subq $-64, %rsi
> - subq $-64, %rdi
> -
> - cmp $64, %rdx
> - ja L(less128bytesin2aligned)
> -
> - cmp $32, %rdx
> - ja L(aligned_last_64_bytes)
> -
> - movdqu -32(%rdi, %rdx), %xmm0
> - movdqu -32(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end_16)
> -
> - movdqu -16(%rdi, %rdx), %xmm0
> - movdqu -16(%rsi, %rdx), %xmm1
> - CMPEQ %xmm0, %xmm1
> - pmovmskb %xmm1, %eax
> - incw %ax
> - jnz L(vec_return_end)
> - ret
> -
> - .p2align 4
> -L(aligned_loop):
> -# ifdef DATA_CACHE_SIZE_HALF
> - mov $DATA_CACHE_SIZE_HALF, %R8_LP
> -# else
> - mov __x86_data_cache_size_half(%rip), %R8_LP
> -# endif
> - movq %r8, %r9
> - addq %r8, %r8
> - addq %r9, %r8
> - cmpq %r8, %rdx
> - ja L(L2_L3_cache_aligned)
> -
> - sub $64, %rdx
> - .p2align 4
> -L(64bytesormore_loopin2aligned):
> - movdqa (%rdi), %xmm0
> - movdqa 16(%rdi), %xmm1
> - movdqa 32(%rdi), %xmm2
> - movdqa 48(%rdi), %xmm3
> -
> - CMPEQ (%rsi), %xmm0
> - CMPEQ 16(%rsi), %xmm1
> - CMPEQ 32(%rsi), %xmm2
> - CMPEQ 48(%rsi), %xmm3
> -
> - pand %xmm0, %xmm1
> - pand %xmm2, %xmm3
> - pand %xmm1, %xmm3
> -
> - pmovmskb %xmm3, %eax
> - incw %ax
> - jnz L(64bytesormore_loop_end)
> - add $64, %rsi
> - add $64, %rdi
> - sub $64, %rdx
> - ja L(64bytesormore_loopin2aligned)
> - jmp L(loop_tail)
> -
> -L(L2_L3_cache_aligned):
> - subq $64, %rdx
> - .p2align 4
> -L(L2_L3_aligned_128bytes_loop):
> - prefetchnta 0x1c0(%rdi)
> - prefetchnta 0x1c0(%rsi)
> - movdqa (%rdi), %xmm0
> - movdqa 16(%rdi), %xmm1
> - movdqa 32(%rdi), %xmm2
> - movdqa 48(%rdi), %xmm3
> -
> - CMPEQ (%rsi), %xmm0
> - CMPEQ 16(%rsi), %xmm1
> - CMPEQ 32(%rsi), %xmm2
> - CMPEQ 48(%rsi), %xmm3
> -
> - pand %xmm0, %xmm1
> - pand %xmm2, %xmm3
> - pand %xmm1, %xmm3
> -
> - pmovmskb %xmm3, %eax
> - incw %ax
> - jnz L(64bytesormore_loop_end)
> -
> - addq $64, %rsi
> - addq $64, %rdi
> - subq $64, %rdx
> - ja L(L2_L3_aligned_128bytes_loop)
> - jmp L(loop_tail)
> -
> - .p2align 4
> -L(64bytesormore_loop_end):
> - pmovmskb %xmm0, %ecx
> - incw %cx
> - jnz L(loop_end_ret)
> -
> - pmovmskb %xmm1, %ecx
> - notw %cx
> - sall $16, %ecx
> - jnz L(loop_end_ret)
> -
> - pmovmskb %xmm2, %ecx
> - notw %cx
> - shlq $32, %rcx
> - jnz L(loop_end_ret)
> -
> - addq $48, %rdi
> - addq $48, %rsi
> - movq %rax, %rcx
> -
> - .p2align 4,, 6
> -L(loop_end_ret):
> - bsfq %rcx, %rcx
> -# ifdef USE_AS_WMEMCMP
> - movl (%rdi, %rcx), %eax
> - xorl %edx, %edx
> - cmpl (%rsi, %rcx), %eax
> - setg %dl
> - leal -1(%rdx, %rdx), %eax
> -# else
> - movzbl (%rdi, %rcx), %eax
> - movzbl (%rsi, %rcx), %ecx
> - subl %ecx, %eax
> -# endif
> - ret
> -END (MEMCMP)
> -#endif
> --
> 2.25.1
>
--
H.J.
next prev parent reply other threads:[~2022-04-15 17:32 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-15 5:51 [PATCH v1 1/3] x86: Optimize memcmp SSE2 in memcmp.S Noah Goldstein
2022-04-15 5:51 ` [PATCH v1 2/3] x86: Remove memcmp-sse4.S Noah Goldstein
2022-04-15 17:20 ` H.J. Lu
2022-04-15 17:29 ` Noah Goldstein
2022-04-15 5:51 ` [PATCH v1 3/3] x86: Cleanup page cross code in memcmp-avx2-movbe.S Noah Goldstein
2022-04-15 17:21 ` H.J. Lu
2022-04-15 17:13 ` [PATCH v1 1/3] x86: Optimize memcmp SSE2 in memcmp.S H.J. Lu
2022-04-15 17:25 ` [PATCH v2 " Noah Goldstein
2022-04-15 17:25 ` [PATCH v2 2/3] x86: Remove memcmp-sse4.S Noah Goldstein
2022-04-15 17:25 ` [PATCH v2 3/3] x86: Cleanup page cross code in memcmp-avx2-movbe.S Noah Goldstein
2022-04-15 17:27 ` [PATCH v3 1/3] x86: Optimize memcmp SSE2 in memcmp.S Noah Goldstein
2022-04-15 17:28 ` [PATCH v3 2/3] x86: Remove memcmp-sse4.S Noah Goldstein
2022-04-15 17:32 ` H.J. Lu [this message]
2022-05-12 20:01 ` Sunil Pandey
2022-04-15 17:28 ` [PATCH v3 3/3] x86: Cleanup page cross code in memcmp-avx2-movbe.S Noah Goldstein
2022-04-15 17:33 ` H.J. Lu
2022-05-12 20:03 ` Sunil Pandey
2022-04-15 17:33 ` [PATCH v3 1/3] x86: Optimize memcmp SSE2 in memcmp.S H.J. Lu
2022-04-15 18:44 ` Noah Goldstein
2022-04-19 20:30 ` Joseph Myers
2022-04-19 20:53 ` Noah Goldstein
2022-04-19 22:56 ` Noah Goldstein
2022-04-20 1:19 ` Noah Goldstein
2022-05-12 19:59 ` Sunil Pandey
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