x86-64: Optimize strchr/strchrnul/wcschr with AVX2

Optimize strchr/strchrnul/wcschr with AVX2 to search 32 bytes with vector
instructions.  It is as fast as SSE2 versions for size <= 16 bytes and up
to 1X faster for or size > 16 bytes on Haswell.  Select AVX2 version on
AVX2 machines where vzeroupper is preferred and AVX unaligned load is fast.

NB: It uses TZCNT instead of BSF since TZCNT produces the same result
as BSF for non-zero input.  TZCNT is faster than BSF and is executed
as BSF if machine doesn't support TZCNT.

	* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
	strchr-sse2, strchrnul-sse2, strchr-avx2, strchrnul-avx2,
	wcschr-sse2 and wcschr-avx2.
	* sysdeps/x86_64/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Add tests for __strchr_avx2,
	__strchrnul_avx2, __strchrnul_sse2, __wcschr_avx2 and
	__wcschr_sse2.
	* sysdeps/x86_64/multiarch/strchr-avx2.S: New file.
	* sysdeps/x86_64/multiarch/strchr-sse2.S: Likewise.
	* sysdeps/x86_64/multiarch/strchr.c: Likewise.
	* sysdeps/x86_64/multiarch/strchrnul-avx2.S: Likewise.
	* sysdeps/x86_64/multiarch/strchrnul-sse2.S: Likewise.
	* sysdeps/x86_64/multiarch/strchrnul.c: Likewise.
	* sysdeps/x86_64/multiarch/wcschr-avx2.S: Likewise.
	* sysdeps/x86_64/multiarch/wcschr-sse2.S: Likewise.
	* sysdeps/x86_64/multiarch/wcschr.c: Likewise.
	* sysdeps/x86_64/multiarch/strchr.S: Removed.

1 files changed, 0 insertions, 57 deletions

diff --git a/sysdeps/x86_64/multiarch/strchr.S b/sysdeps/x86_64/multiarch/strchr.S
deleted file mode 100644
index c9f54ca2e2..0000000000
--- a/sysdeps/x86_64/multiarch/strchr.S
+++ /dev/null
@@ -1,57 +0,0 @@
-/* Multiple versions of strchr
-   Copyright (C) 2009-2017 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
-   <http://www.gnu.org/licenses/>.  */
-
-#include <sysdep.h>
-#include <init-arch.h>
-
-
-/* Define multiple versions only for the definition in libc.  */
-#if IS_IN (libc)
-	.text
-ENTRY(strchr)
-	.type	strchr, @gnu_indirect_function
-	LOAD_RTLD_GLOBAL_RO_RDX
-	leaq	__strchr_sse2(%rip), %rax
-2:	HAS_ARCH_FEATURE (Slow_BSF)
-	jz	3f
-	leaq    __strchr_sse2_no_bsf(%rip), %rax
-3:	ret
-END(strchr)
-
-
-
-# undef ENTRY
-# define ENTRY(name) \
-	.type __strchr_sse2, @function; \
-	.align 16; \
-	.globl __strchr_sse2; \
-	.hidden __strchr_sse2; \
-	__strchr_sse2: cfi_startproc; \
-	CALL_MCOUNT
-# undef END
-# define END(name) \
-	cfi_endproc; .size __strchr_sse2, .-__strchr_sse2
-# undef libc_hidden_builtin_def
-/* It doesn't make sense to send libc-internal strchr calls through a PLT.
-   The speedup we get from using SSE4.2 instruction is likely eaten away
-   by the indirect call in the PLT.  */
-# define libc_hidden_builtin_def(name) \
-	.globl __GI_strchr; __GI_strchr = __strchr_sse2
-#endif
-
-#include "../strchr.S"