From bb034f8ae84535c1263032311594f229fd3ad1a9 Mon Sep 17 00:00:00 2001

From: Noah Goldstein <goldstein.w.n@gmail.com>

Date: Wed, 23 Mar 2022 16:57:26 -0500

Subject: [PATCH] x86: Remove strcspn-sse2.S and use the generic implementation

The generic implementation is faster.

geometric_mean(N=20) of all benchmarks New / Original: .678

All string/memory tests pass.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

(cherry picked from commit fe28e7d9d9535ebab4081d195c553b4fbf39d9ae)

---

 .../{strcspn-sse2.S => strcspn-sse2.c}        |   6 +-

 sysdeps/x86_64/strcspn.S                      | 122 ------------------

 2 files changed, 3 insertions(+), 125 deletions(-)

 rename sysdeps/x86_64/multiarch/{strcspn-sse2.S => strcspn-sse2.c} (89%)

 delete mode 100644 sysdeps/x86_64/strcspn.S

diff --git a/sysdeps/x86_64/multiarch/strcspn-sse2.S b/sysdeps/x86_64/multiarch/strcspn-sse2.c

similarity index 89%

rename from sysdeps/x86_64/multiarch/strcspn-sse2.S

rename to sysdeps/x86_64/multiarch/strcspn-sse2.c

index 8a0c69d7..32debee4 100644

--- a/sysdeps/x86_64/multiarch/strcspn-sse2.S

+++ b/sysdeps/x86_64/multiarch/strcspn-sse2.c

@@ -19,10 +19,10 @@

 #if IS_IN (libc)

 # include <sysdep.h>

-# define strcspn __strcspn_sse2

+# define STRCSPN __strcspn_sse2

 # undef libc_hidden_builtin_def

-# define libc_hidden_builtin_def(strcspn)

+# define libc_hidden_builtin_def(STRCSPN)

 #endif

-#include <sysdeps/x86_64/strcspn.S>

+#include <string/strcspn.c>

diff --git a/sysdeps/x86_64/strcspn.S b/sysdeps/x86_64/strcspn.S

deleted file mode 100644

index 7f9202d6..00000000

--- a/sysdeps/x86_64/strcspn.S

+++ /dev/null

@@ -1,122 +0,0 @@

-/* strcspn (str, ss) -- Return the length of the initial segment of STR

-			which contains no characters from SS.

-   For AMD x86-64.

-   Copyright (C) 1994-2018 Free Software Foundation, Inc.

-   This file is part of the GNU C Library.

-   Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>.

-   Bug fixes by Alan Modra <Alan@SPRI.Levels.UniSA.Edu.Au>.

-   Adopted for x86-64 by Andreas Jaeger <aj@suse.de>.

-

-   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

-   <http://www.gnu.org/licenses/>.  */

-

-#include <sysdep.h>

-#include "asm-syntax.h"

-

-	.text

-ENTRY (strcspn)

-

-	movq %rdi, %rdx		/* Save SRC.  */

-

-	/* First we create a table with flags for all possible characters.

-	   For the ASCII (7bit/8bit) or ISO-8859-X character sets which are

-	   supported by the C string functions we have 256 characters.

-	   Before inserting marks for the stop characters we clear the whole

-	   table.  */

-	movq %rdi, %r8			/* Save value.  */

-	subq $256, %rsp			/* Make space for 256 bytes.  */

-	cfi_adjust_cfa_offset(256)

-	movl $32,  %ecx			/* 32*8 bytes = 256 bytes.  */

-	movq %rsp, %rdi

-	xorl %eax, %eax			/* We store 0s.  */

-	cld

-	rep

-	stosq

-

-	movq %rsi, %rax			/* Setup skipset.  */

-

-/* For understanding the following code remember that %rcx == 0 now.

-   Although all the following instruction only modify %cl we always

-   have a correct zero-extended 64-bit value in %rcx.  */

-

-	.p2align 4

-L(2):	movb (%rax), %cl	/* get byte from skipset */

-	testb %cl, %cl		/* is NUL char? */

-	jz L(1)			/* yes => start compare loop */

-	movb %cl, (%rsp,%rcx)	/* set corresponding byte in skipset table */

-

-	movb 1(%rax), %cl	/* get byte from skipset */

-	testb $0xff, %cl	/* is NUL char? */

-	jz L(1)			/* yes => start compare loop */

-	movb %cl, (%rsp,%rcx)	/* set corresponding byte in skipset table */

-

-	movb 2(%rax), %cl	/* get byte from skipset */

-	testb $0xff, %cl	/* is NUL char? */

-	jz L(1)			/* yes => start compare loop */

-	movb %cl, (%rsp,%rcx)	/* set corresponding byte in skipset table */

-

-	movb 3(%rax), %cl	/* get byte from skipset */

-	addq $4, %rax		/* increment skipset pointer */

-	movb %cl, (%rsp,%rcx)	/* set corresponding byte in skipset table */

-	testb $0xff, %cl	/* is NUL char? */

-	jnz L(2)		/* no => process next dword from skipset */

-

-L(1):	leaq -4(%rdx), %rax	/* prepare loop */

-

-	/* We use a neat trick for the following loop.  Normally we would

-	   have to test for two termination conditions

-	   1. a character in the skipset was found

-	   and

-	   2. the end of the string was found

-	   But as a sign that the character is in the skipset we store its

-	   value in the table.  But the value of NUL is NUL so the loop

-	   terminates for NUL in every case.  */

-

-	.p2align 4

-L(3):	addq $4, %rax		/* adjust pointer for full loop round */

-

-	movb (%rax), %cl	/* get byte from string */

-	cmpb %cl, (%rsp,%rcx)	/* is it contained in skipset? */

-	je L(4)			/* yes => return */

-

-	movb 1(%rax), %cl	/* get byte from string */

-	cmpb %cl, (%rsp,%rcx)	/* is it contained in skipset? */

-	je L(5)			/* yes => return */

-

-	movb 2(%rax), %cl	/* get byte from string */

-	cmpb %cl, (%rsp,%rcx)	/* is it contained in skipset? */

-	jz L(6)			/* yes => return */

-

-	movb 3(%rax), %cl	/* get byte from string */

-	cmpb %cl, (%rsp,%rcx)	/* is it contained in skipset? */

-	jne L(3)		/* no => start loop again */

-

-	incq %rax		/* adjust pointer */

-L(6):	incq %rax

-L(5):	incq %rax

-

-L(4):	addq $256, %rsp		/* remove skipset */

-	cfi_adjust_cfa_offset(-256)

-#ifdef USE_AS_STRPBRK

-	xorl %edx,%edx

-	orb %cl, %cl		/* was last character NUL? */

-	cmovzq %rdx, %rax	/* Yes:	return NULL */

-#else

-	subq %rdx, %rax		/* we have to return the number of valid

-				   characters, so compute distance to first

-				   non-valid character */

-#endif

-	ret

-END (strcspn)

-libc_hidden_builtin_def (strcspn)

-- 

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