360 lines
8.8 KiB
Diff
360 lines
8.8 KiB
Diff
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From 1f745ecc2109890886b161d4791e1406fdfc29b8 Mon Sep 17 00:00:00 2001
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From: noah <goldstein.w.n@gmail.com>
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Date: Wed, 3 Feb 2021 00:38:59 -0500
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Subject: [PATCH] x86-64: Refactor and improve performance of strchr-avx2.S
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Content-type: text/plain; charset=UTF-8
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No bug. Just seemed the performance could be improved a bit. Observed
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and expected behavior are unchanged. Optimized body of main
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loop. Updated page cross logic and optimized accordingly. Made a few
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minor instruction selection modifications. No regressions in test
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suite. Both test-strchrnul and test-strchr passed.
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---
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sysdeps/x86_64/multiarch/strchr-avx2.S | 225 ++++++++++++-------------
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sysdeps/x86_64/multiarch/strchr.c | 4 +-
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2 files changed, 114 insertions(+), 115 deletions(-)
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Conflicts:
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sysdeps/x86_64/multiarch/strchr.c
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(account for missing upstream macros)
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diff --git a/sysdeps/x86_64/multiarch/strchr-avx2.S b/sysdeps/x86_64/multiarch/strchr-avx2.S
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index da7d2620..919d256c 100644
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--- a/sysdeps/x86_64/multiarch/strchr-avx2.S
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+++ b/sysdeps/x86_64/multiarch/strchr-avx2.S
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@@ -27,10 +27,12 @@
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# ifdef USE_AS_WCSCHR
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# define VPBROADCAST vpbroadcastd
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# define VPCMPEQ vpcmpeqd
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+# define VPMINU vpminud
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# define CHAR_REG esi
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# else
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# define VPBROADCAST vpbroadcastb
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# define VPCMPEQ vpcmpeqb
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+# define VPMINU vpminub
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# define CHAR_REG sil
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# endif
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@@ -43,71 +45,54 @@
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# endif
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# define VEC_SIZE 32
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+# define PAGE_SIZE 4096
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.section SECTION(.text),"ax",@progbits
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ENTRY (STRCHR)
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movl %edi, %ecx
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- /* Broadcast CHAR to YMM0. */
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+# ifndef USE_AS_STRCHRNUL
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+ xorl %edx, %edx
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+# endif
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+
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+ /* Broadcast CHAR to YMM0. */
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vmovd %esi, %xmm0
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vpxor %xmm9, %xmm9, %xmm9
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VPBROADCAST %xmm0, %ymm0
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- /* Check if we may cross page boundary with one vector load. */
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- andl $(2 * VEC_SIZE - 1), %ecx
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- cmpl $VEC_SIZE, %ecx
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- ja L(cros_page_boundary)
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- /* Check the first VEC_SIZE bytes. Search for both CHAR and the
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- null byte. */
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- vmovdqu (%rdi), %ymm8
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- VPCMPEQ %ymm8, %ymm0, %ymm1
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- VPCMPEQ %ymm8, %ymm9, %ymm2
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- vpor %ymm1, %ymm2, %ymm1
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- vpmovmskb %ymm1, %eax
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- testl %eax, %eax
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- jnz L(first_vec_x0)
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+ /* Check if we cross page boundary with one vector load. */
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+ andl $(PAGE_SIZE - 1), %ecx
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+ cmpl $(PAGE_SIZE - VEC_SIZE), %ecx
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+ ja L(cross_page_boundary)
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- /* Align data for aligned loads in the loop. */
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- addq $VEC_SIZE, %rdi
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- andl $(VEC_SIZE - 1), %ecx
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- andq $-VEC_SIZE, %rdi
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-
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- jmp L(more_4x_vec)
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-
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- .p2align 4
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-L(cros_page_boundary):
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- andl $(VEC_SIZE - 1), %ecx
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- andq $-VEC_SIZE, %rdi
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+ /* Check the first VEC_SIZE bytes. Search for both CHAR and the
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+ null byte. */
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vmovdqu (%rdi), %ymm8
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VPCMPEQ %ymm8, %ymm0, %ymm1
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VPCMPEQ %ymm8, %ymm9, %ymm2
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vpor %ymm1, %ymm2, %ymm1
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vpmovmskb %ymm1, %eax
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- /* Remove the leading bytes. */
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- sarl %cl, %eax
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testl %eax, %eax
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- jz L(aligned_more)
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- /* Found CHAR or the null byte. */
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+ jz L(more_vecs)
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tzcntl %eax, %eax
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- addq %rcx, %rax
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-# ifdef USE_AS_STRCHRNUL
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+ /* Found CHAR or the null byte. */
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addq %rdi, %rax
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-# else
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- xorl %edx, %edx
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- leaq (%rdi, %rax), %rax
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- cmp (%rax), %CHAR_REG
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+# ifndef USE_AS_STRCHRNUL
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+ cmp (%rax), %CHAR_REG
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cmovne %rdx, %rax
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# endif
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L(return_vzeroupper):
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ZERO_UPPER_VEC_REGISTERS_RETURN
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.p2align 4
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+L(more_vecs):
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+ /* Align data for aligned loads in the loop. */
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+ andq $-VEC_SIZE, %rdi
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L(aligned_more):
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- addq $VEC_SIZE, %rdi
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-L(more_4x_vec):
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- /* Check the first 4 * VEC_SIZE. Only one VEC_SIZE at a time
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- since data is only aligned to VEC_SIZE. */
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- vmovdqa (%rdi), %ymm8
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+ /* Check the next 4 * VEC_SIZE. Only one VEC_SIZE at a time
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+ since data is only aligned to VEC_SIZE. */
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+ vmovdqa VEC_SIZE(%rdi), %ymm8
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+ addq $VEC_SIZE, %rdi
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VPCMPEQ %ymm8, %ymm0, %ymm1
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VPCMPEQ %ymm8, %ymm9, %ymm2
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vpor %ymm1, %ymm2, %ymm1
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@@ -137,61 +122,24 @@ L(more_4x_vec):
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vpor %ymm1, %ymm2, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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- jnz L(first_vec_x3)
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-
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- addq $(VEC_SIZE * 4), %rdi
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-
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- /* Align data to 4 * VEC_SIZE. */
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- movq %rdi, %rcx
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- andl $(4 * VEC_SIZE - 1), %ecx
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- andq $-(4 * VEC_SIZE), %rdi
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-
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- .p2align 4
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-L(loop_4x_vec):
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- /* Compare 4 * VEC at a time forward. */
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- vmovdqa (%rdi), %ymm5
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- vmovdqa VEC_SIZE(%rdi), %ymm6
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- vmovdqa (VEC_SIZE * 2)(%rdi), %ymm7
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- vmovdqa (VEC_SIZE * 3)(%rdi), %ymm8
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-
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- VPCMPEQ %ymm5, %ymm0, %ymm1
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- VPCMPEQ %ymm6, %ymm0, %ymm2
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- VPCMPEQ %ymm7, %ymm0, %ymm3
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- VPCMPEQ %ymm8, %ymm0, %ymm4
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-
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- VPCMPEQ %ymm5, %ymm9, %ymm5
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- VPCMPEQ %ymm6, %ymm9, %ymm6
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- VPCMPEQ %ymm7, %ymm9, %ymm7
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- VPCMPEQ %ymm8, %ymm9, %ymm8
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-
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- vpor %ymm1, %ymm5, %ymm1
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- vpor %ymm2, %ymm6, %ymm2
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- vpor %ymm3, %ymm7, %ymm3
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- vpor %ymm4, %ymm8, %ymm4
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-
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- vpor %ymm1, %ymm2, %ymm5
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- vpor %ymm3, %ymm4, %ymm6
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-
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- vpor %ymm5, %ymm6, %ymm5
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-
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- vpmovmskb %ymm5, %eax
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- testl %eax, %eax
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- jnz L(4x_vec_end)
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-
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- addq $(VEC_SIZE * 4), %rdi
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+ jz L(prep_loop_4x)
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- jmp L(loop_4x_vec)
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+ tzcntl %eax, %eax
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+ leaq (VEC_SIZE * 3)(%rdi, %rax), %rax
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+# ifndef USE_AS_STRCHRNUL
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+ cmp (%rax), %CHAR_REG
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+ cmovne %rdx, %rax
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+# endif
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+ VZEROUPPER
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+ ret
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.p2align 4
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L(first_vec_x0):
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- /* Found CHAR or the null byte. */
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tzcntl %eax, %eax
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-# ifdef USE_AS_STRCHRNUL
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+ /* Found CHAR or the null byte. */
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addq %rdi, %rax
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-# else
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- xorl %edx, %edx
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- leaq (%rdi, %rax), %rax
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- cmp (%rax), %CHAR_REG
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+# ifndef USE_AS_STRCHRNUL
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+ cmp (%rax), %CHAR_REG
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cmovne %rdx, %rax
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# endif
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VZEROUPPER_RETURN
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@@ -199,13 +147,9 @@ L(first_vec_x0):
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.p2align 4
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L(first_vec_x1):
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tzcntl %eax, %eax
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-# ifdef USE_AS_STRCHRNUL
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- addq $VEC_SIZE, %rax
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- addq %rdi, %rax
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-# else
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- xorl %edx, %edx
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leaq VEC_SIZE(%rdi, %rax), %rax
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- cmp (%rax), %CHAR_REG
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+# ifndef USE_AS_STRCHRNUL
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+ cmp (%rax), %CHAR_REG
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cmovne %rdx, %rax
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# endif
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VZEROUPPER_RETURN
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@@ -213,42 +157,97 @@ L(first_vec_x1):
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.p2align 4
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L(first_vec_x2):
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tzcntl %eax, %eax
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-# ifdef USE_AS_STRCHRNUL
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- addq $(VEC_SIZE * 2), %rax
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- addq %rdi, %rax
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-# else
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- xorl %edx, %edx
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+ /* Found CHAR or the null byte. */
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leaq (VEC_SIZE * 2)(%rdi, %rax), %rax
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- cmp (%rax), %CHAR_REG
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+# ifndef USE_AS_STRCHRNUL
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+ cmp (%rax), %CHAR_REG
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cmovne %rdx, %rax
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# endif
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VZEROUPPER_RETURN
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+L(prep_loop_4x):
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+ /* Align data to 4 * VEC_SIZE. */
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+ andq $-(VEC_SIZE * 4), %rdi
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+
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.p2align 4
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-L(4x_vec_end):
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+L(loop_4x_vec):
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+ /* Compare 4 * VEC at a time forward. */
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+ vmovdqa (VEC_SIZE * 4)(%rdi), %ymm5
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+ vmovdqa (VEC_SIZE * 5)(%rdi), %ymm6
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+ vmovdqa (VEC_SIZE * 6)(%rdi), %ymm7
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+ vmovdqa (VEC_SIZE * 7)(%rdi), %ymm8
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+
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+ /* Leaves only CHARS matching esi as 0. */
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+ vpxor %ymm5, %ymm0, %ymm1
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+ vpxor %ymm6, %ymm0, %ymm2
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+ vpxor %ymm7, %ymm0, %ymm3
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+ vpxor %ymm8, %ymm0, %ymm4
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+
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+ VPMINU %ymm1, %ymm5, %ymm1
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+ VPMINU %ymm2, %ymm6, %ymm2
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+ VPMINU %ymm3, %ymm7, %ymm3
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+ VPMINU %ymm4, %ymm8, %ymm4
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+
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+ VPMINU %ymm1, %ymm2, %ymm5
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+ VPMINU %ymm3, %ymm4, %ymm6
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+
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+ VPMINU %ymm5, %ymm6, %ymm5
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+
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+ VPCMPEQ %ymm5, %ymm9, %ymm5
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+ vpmovmskb %ymm5, %eax
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+
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+ addq $(VEC_SIZE * 4), %rdi
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+ testl %eax, %eax
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+ jz L(loop_4x_vec)
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+
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+ VPCMPEQ %ymm1, %ymm9, %ymm1
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vpmovmskb %ymm1, %eax
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testl %eax, %eax
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jnz L(first_vec_x0)
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+
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+ VPCMPEQ %ymm2, %ymm9, %ymm2
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vpmovmskb %ymm2, %eax
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testl %eax, %eax
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jnz L(first_vec_x1)
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- vpmovmskb %ymm3, %eax
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- testl %eax, %eax
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- jnz L(first_vec_x2)
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+
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+ VPCMPEQ %ymm3, %ymm9, %ymm3
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+ VPCMPEQ %ymm4, %ymm9, %ymm4
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+ vpmovmskb %ymm3, %ecx
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vpmovmskb %ymm4, %eax
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+ salq $32, %rax
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+ orq %rcx, %rax
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+ tzcntq %rax, %rax
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+ leaq (VEC_SIZE * 2)(%rdi, %rax), %rax
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+# ifndef USE_AS_STRCHRNUL
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+ cmp (%rax), %CHAR_REG
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+ cmovne %rdx, %rax
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+# endif
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+ VZEROUPPER
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+ ret
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+
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+ /* Cold case for crossing page with first load. */
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+ .p2align 4
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+L(cross_page_boundary):
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+ andq $-VEC_SIZE, %rdi
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+ andl $(VEC_SIZE - 1), %ecx
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+
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+ vmovdqa (%rdi), %ymm8
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+ VPCMPEQ %ymm8, %ymm0, %ymm1
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+ VPCMPEQ %ymm8, %ymm9, %ymm2
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+ vpor %ymm1, %ymm2, %ymm1
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+ vpmovmskb %ymm1, %eax
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+ /* Remove the leading bits. */
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+ sarxl %ecx, %eax, %eax
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testl %eax, %eax
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-L(first_vec_x3):
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+ jz L(aligned_more)
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tzcntl %eax, %eax
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-# ifdef USE_AS_STRCHRNUL
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- addq $(VEC_SIZE * 3), %rax
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+ addq %rcx, %rdi
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addq %rdi, %rax
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-# else
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- xorl %edx, %edx
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- leaq (VEC_SIZE * 3)(%rdi, %rax), %rax
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- cmp (%rax), %CHAR_REG
|
||
|
|
+# ifndef USE_AS_STRCHRNUL
|
||
|
|
+ cmp (%rax), %CHAR_REG
|
||
|
|
cmovne %rdx, %rax
|
||
|
|
# endif
|
||
|
|
VZEROUPPER_RETURN
|
||
|
|
|
||
|
|
END (STRCHR)
|
||
|
|
-#endif
|
||
|
|
+# endif
|
||
|
|
diff --git a/sysdeps/x86_64/multiarch/strchr.c b/sysdeps/x86_64/multiarch/strchr.c
|
||
|
|
index 7e582f02..5225bd4f 100644
|
||
|
|
--- a/sysdeps/x86_64/multiarch/strchr.c
|
||
|
|
+++ b/sysdeps/x86_64/multiarch/strchr.c
|
||
|
|
@@ -38,11 +38,11 @@ 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)
|
||
|
|
- && CPU_FEATURE_USABLE_P (cpu_features, BMI2))
|
||
|
|
+ && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
|
||
|
|
return OPTIMIZE (evex);
|
||
|
|
|
||
|
|
if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
|
||
|
|
--
|
||
|
|
GitLab
|
||
|
|
|