commit eb9aa96facc5231e208de0946870f10c21aee9f3

Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>

Date:   Fri May 13 09:33:30 2022 -0300

    x86_64: Remove bzero optimization

    Both symbols are marked as legacy in POSIX.1-2001 and removed on

    POSIX.1-2008, although the prototypes are defined for _GNU_SOURCE

    or _DEFAULT_SOURCE.

    GCC also replaces bcopy with a memmove and bzero with memset on default

    configuration (to actually get a bzero libc call the code requires

    to omit string.h inclusion and built with -fno-builtin), so it is

    highly unlikely programs are actually calling libc bzero symbol.

    On a recent Linux distro (Ubuntu 22.04), there is no bzero calls

    by the installed binaries.

      $ cat count_bstring.sh

      #!/bin/bash

      files=`IFS=':';for i in $PATH; do test -d "$i" && find "$i" -maxdepth 1 -executable -type f; done`

      total=0

      for file in $files; do

        symbols=`objdump -R $file 2>&1`

        if [ $? -eq 0 ]; then

          ncalls=`echo $symbols | grep -w $1 | wc -l`

          ((total=total+ncalls))

          if [ $ncalls -gt 0 ]; then

            echo "$file: $ncalls"

          fi

        fi

      done

      echo "TOTAL=$total"

      $ ./count_bstring.sh bzero

      TOTAL=0

    Checked on x86_64-linux-gnu.

    (cherry picked from commit 9403b71ae97e3f1a91c796ddcbb4e6f044434734)

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

deleted file mode 100644

index f96d567fd87696af..0000000000000000

--- a/sysdeps/x86_64/bzero.S

+++ /dev/null

@@ -1 +0,0 @@

-/* Implemented in memset.S.  */

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

index 0358210c7ff3a976..2b64741fd10a8ec2 100644

--- a/sysdeps/x86_64/memset.S

+++ b/sysdeps/x86_64/memset.S

@@ -1,4 +1,4 @@

-/* memset/bzero -- set memory area to CH/0

+/* memset -- set memory area to CH/0

    Optimized version for x86-64.

    Copyright (C) 2002-2021 Free Software Foundation, Inc.

    This file is part of the GNU C Library.

@@ -35,9 +35,6 @@

   punpcklwd %xmm0, %xmm0; \

   pshufd $0, %xmm0, %xmm0

-# define BZERO_ZERO_VEC0() \

-  pxor %xmm0, %xmm0

-

 # define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \

   movd d, %xmm0; \

   pshufd $0, %xmm0, %xmm0; \

@@ -56,10 +53,6 @@

 # define MEMSET_SYMBOL(p,s)	memset

 #endif

-#ifndef BZERO_SYMBOL

-# define BZERO_SYMBOL(p,s)	__bzero

-#endif

-

 #ifndef WMEMSET_SYMBOL

 # define WMEMSET_CHK_SYMBOL(p,s) p

 # define WMEMSET_SYMBOL(p,s)	__wmemset

@@ -70,7 +63,6 @@

 libc_hidden_builtin_def (memset)

 #if IS_IN (libc)

-weak_alias (__bzero, bzero)

 libc_hidden_def (__wmemset)

 weak_alias (__wmemset, wmemset)

 libc_hidden_weak (wmemset)

diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile

index b503e4b81e92a11c..67401162d526f664 100644

--- a/sysdeps/x86_64/multiarch/Makefile

+++ b/sysdeps/x86_64/multiarch/Makefile

@@ -1,7 +1,6 @@

 ifeq ($(subdir),string)

 sysdep_routines += \

-  bzero \

   memchr-avx2 \

   memchr-avx2-rtm \

   memchr-evex \

diff --git a/sysdeps/x86_64/multiarch/bzero.c b/sysdeps/x86_64/multiarch/bzero.c

deleted file mode 100644

index 13e399a9a1fbdeb2..0000000000000000

--- a/sysdeps/x86_64/multiarch/bzero.c

+++ /dev/null

@@ -1,108 +0,0 @@

-/* Multiple versions of bzero.

-   All versions must be listed in ifunc-impl-list.c.

-   Copyright (C) 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/>.  */

-

-/* Define multiple versions only for the definition in libc.  */

-#if IS_IN (libc)

-# define __bzero __redirect___bzero

-# include <string.h>

-# undef __bzero

-

-/* OPTIMIZE1 definition required for bzero patch.  */

-# define OPTIMIZE1(name)	EVALUATOR1 (SYMBOL_NAME, name)

-# define SYMBOL_NAME __bzero

-# include <init-arch.h>

-

-extern __typeof (REDIRECT_NAME) OPTIMIZE1 (sse2_unaligned)

-  attribute_hidden;

-extern __typeof (REDIRECT_NAME) OPTIMIZE1 (sse2_unaligned_erms)

-  attribute_hidden;

-extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx2_unaligned) attribute_hidden;

-extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx2_unaligned_erms)

-  attribute_hidden;

-extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx2_unaligned_rtm)

-  attribute_hidden;

-extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx2_unaligned_erms_rtm)

-  attribute_hidden;

-extern __typeof (REDIRECT_NAME) OPTIMIZE1 (evex_unaligned)

-  attribute_hidden;

-extern __typeof (REDIRECT_NAME) OPTIMIZE1 (evex_unaligned_erms)

-  attribute_hidden;

-extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx512_unaligned)

-  attribute_hidden;

-extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx512_unaligned_erms)

-  attribute_hidden;

-

-static inline void *

-IFUNC_SELECTOR (void)

-{

-  const struct cpu_features* cpu_features = __get_cpu_features ();

-

-  if (CPU_FEATURE_USABLE_P (cpu_features, AVX512F)

-      && !CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_AVX512))

-    {

-      if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)

-          && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)

-          && CPU_FEATURE_USABLE_P (cpu_features, BMI2))

-	{

-	  if (CPU_FEATURE_USABLE_P (cpu_features, ERMS))

-	    return OPTIMIZE1 (avx512_unaligned_erms);

-

-	  return OPTIMIZE1 (avx512_unaligned);

-	}

-    }

-

-  if (CPU_FEATURE_USABLE_P (cpu_features, AVX2))

-    {

-      if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)

-          && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)

-          && CPU_FEATURE_USABLE_P (cpu_features, BMI2))

-	{

-	  if (CPU_FEATURE_USABLE_P (cpu_features, ERMS))

-	    return OPTIMIZE1 (evex_unaligned_erms);

-

-	  return OPTIMIZE1 (evex_unaligned);

-	}

-

-      if (CPU_FEATURE_USABLE_P (cpu_features, RTM))

-	{

-	  if (CPU_FEATURE_USABLE_P (cpu_features, ERMS))

-	    return OPTIMIZE1 (avx2_unaligned_erms_rtm);

-

-	  return OPTIMIZE1 (avx2_unaligned_rtm);

-	}

-

-      if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))

-	{

-	  if (CPU_FEATURE_USABLE_P (cpu_features, ERMS))

-	    return OPTIMIZE1 (avx2_unaligned_erms);

-

-	  return OPTIMIZE1 (avx2_unaligned);

-	}

-    }

-

-  if (CPU_FEATURE_USABLE_P (cpu_features, ERMS))

-    return OPTIMIZE1 (sse2_unaligned_erms);

-

-  return OPTIMIZE1 (sse2_unaligned);

-}

-

-libc_ifunc_redirected (__redirect___bzero, __bzero, IFUNC_SELECTOR ());

-

-weak_alias (__bzero, bzero)

-#endif

diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c

index e5e48b36c3175e68..d990a7149489efd9 100644

--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c

+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c

@@ -280,48 +280,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,

 			      __memset_avx512_no_vzeroupper)

 	     )

-  /* Support sysdeps/x86_64/multiarch/bzero.c.  */

-  IFUNC_IMPL (i, name, bzero,

-	      IFUNC_IMPL_ADD (array, i, bzero, 1,

-			      __bzero_sse2_unaligned)

-	      IFUNC_IMPL_ADD (array, i, bzero, 1,

-			      __bzero_sse2_unaligned_erms)

-	      IFUNC_IMPL_ADD (array, i, bzero,

-			      CPU_FEATURE_USABLE (AVX2),

-			      __bzero_avx2_unaligned)

-	      IFUNC_IMPL_ADD (array, i, bzero,

-			      CPU_FEATURE_USABLE (AVX2),

-			      __bzero_avx2_unaligned_erms)

-	      IFUNC_IMPL_ADD (array, i, bzero,

-			      (CPU_FEATURE_USABLE (AVX2)

-			       && CPU_FEATURE_USABLE (RTM)),

-			      __bzero_avx2_unaligned_rtm)

-	      IFUNC_IMPL_ADD (array, i, bzero,

-			      (CPU_FEATURE_USABLE (AVX2)

-			       && CPU_FEATURE_USABLE (RTM)),

-			      __bzero_avx2_unaligned_erms_rtm)

-	      IFUNC_IMPL_ADD (array, i, bzero,

-			      (CPU_FEATURE_USABLE (AVX512VL)

-			       && CPU_FEATURE_USABLE (AVX512BW)

-			       && CPU_FEATURE_USABLE (BMI2)),

-			      __bzero_evex_unaligned)

-	      IFUNC_IMPL_ADD (array, i, bzero,

-			      (CPU_FEATURE_USABLE (AVX512VL)

-			       && CPU_FEATURE_USABLE (AVX512BW)

-			       && CPU_FEATURE_USABLE (BMI2)),

-			      __bzero_evex_unaligned_erms)

-	      IFUNC_IMPL_ADD (array, i, bzero,

-			      (CPU_FEATURE_USABLE (AVX512VL)

-			       && CPU_FEATURE_USABLE (AVX512BW)

-			       && CPU_FEATURE_USABLE (BMI2)),

-			      __bzero_avx512_unaligned_erms)

-	      IFUNC_IMPL_ADD (array, i, bzero,

-			      (CPU_FEATURE_USABLE (AVX512VL)

-			       && CPU_FEATURE_USABLE (AVX512BW)

-			       && CPU_FEATURE_USABLE (BMI2)),

-			      __bzero_avx512_unaligned)

-	     )

-

   /* Support sysdeps/x86_64/multiarch/rawmemchr.c.  */

   IFUNC_IMPL (i, name, rawmemchr,

 	      IFUNC_IMPL_ADD (array, i, rawmemchr,

diff --git a/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms-rtm.S b/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms-rtm.S

index 5a5ee6f67299400b..8ac3e479bba488be 100644

--- a/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms-rtm.S

+++ b/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms-rtm.S

@@ -5,7 +5,6 @@

 #define SECTION(p) p##.avx.rtm

 #define MEMSET_SYMBOL(p,s)	p##_avx2_##s##_rtm

-#define BZERO_SYMBOL(p,s)	p##_avx2_##s##_rtm

 #define WMEMSET_SYMBOL(p,s)	p##_avx2_##s##_rtm

 #include "memset-avx2-unaligned-erms.S"

diff --git a/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S

index a093a2831f3dfa0d..c0bf2875d03d51ab 100644

--- a/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S

+++ b/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S

@@ -14,9 +14,6 @@

   vmovd d, %xmm0; \

   movq r, %rax;

-# define BZERO_ZERO_VEC0() \

-  vpxor %xmm0, %xmm0, %xmm0

-

 # define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \

   MEMSET_SET_VEC0_AND_SET_RETURN(d, r)

@@ -32,9 +29,6 @@

 # ifndef MEMSET_SYMBOL

 #  define MEMSET_SYMBOL(p,s)	p##_avx2_##s

 # endif

-# ifndef BZERO_SYMBOL

-#  define BZERO_SYMBOL(p,s)	p##_avx2_##s

-# endif

 # ifndef WMEMSET_SYMBOL

 #  define WMEMSET_SYMBOL(p,s)	p##_avx2_##s

 # endif

diff --git a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S

index 727c92133a15900f..5241216a77bf72b7 100644

--- a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S

+++ b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S

@@ -19,9 +19,6 @@

   vpbroadcastb d, %VEC0; \

   movq r, %rax

-# define BZERO_ZERO_VEC0() \

-  vpxorq %XMM0, %XMM0, %XMM0

-

 # define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \

   vpbroadcastd d, %VEC0; \

   movq r, %rax

diff --git a/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S

index 5d8fa78f05476b10..637002150659123c 100644

--- a/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S

+++ b/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S

@@ -19,9 +19,6 @@

   vpbroadcastb d, %VEC0; \

   movq r, %rax

-# define BZERO_ZERO_VEC0() \

-  vpxorq %XMM0, %XMM0, %XMM0

-

 # define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \

   vpbroadcastd d, %VEC0; \

   movq r, %rax

diff --git a/sysdeps/x86_64/multiarch/memset-sse2-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-sse2-unaligned-erms.S

index 2951f7f5f70e274a..c47f3a9c955508a2 100644

--- a/sysdeps/x86_64/multiarch/memset-sse2-unaligned-erms.S

+++ b/sysdeps/x86_64/multiarch/memset-sse2-unaligned-erms.S

@@ -22,7 +22,6 @@

 #if IS_IN (libc)

 # define MEMSET_SYMBOL(p,s)	p##_sse2_##s

-# define BZERO_SYMBOL(p,s)	MEMSET_SYMBOL (p, s)

 # define WMEMSET_SYMBOL(p,s)	p##_sse2_##s

 # ifdef SHARED

diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S

index d9c577fb5ff9700f..abc12d9cda1b3843 100644

--- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S

+++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S

@@ -1,5 +1,5 @@

-/* memset/bzero with unaligned store and rep stosb

-   Copyright (C) 2016-2021 Free Software Foundation, Inc.

+/* memset with unaligned store and rep stosb

+   Copyright (C) 2016-2022 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

@@ -26,10 +26,6 @@

 #include <sysdep.h>

-#ifndef BZERO_SYMBOL

-# define BZERO_SYMBOL(p,s)		MEMSET_SYMBOL (p, s)

-#endif

-

 #ifndef MEMSET_CHK_SYMBOL

 # define MEMSET_CHK_SYMBOL(p,s)		MEMSET_SYMBOL(p, s)

 #endif

@@ -134,31 +130,6 @@ ENTRY (WMEMSET_SYMBOL (__wmemset, unaligned))

 END (WMEMSET_SYMBOL (__wmemset, unaligned))

 #endif

-ENTRY (BZERO_SYMBOL(__bzero, unaligned))

-#if VEC_SIZE > 16

-	BZERO_ZERO_VEC0 ()

-#endif

-	mov	%RDI_LP, %RAX_LP

-	mov	%RSI_LP, %RDX_LP

-#ifndef USE_LESS_VEC_MASK_STORE

-	xorl	%esi, %esi

-#endif

-	cmp	$VEC_SIZE, %RDX_LP

-	jb	L(less_vec_no_vdup)

-#ifdef USE_LESS_VEC_MASK_STORE

-	xorl	%esi, %esi

-#endif

-#if VEC_SIZE <= 16

-	BZERO_ZERO_VEC0 ()

-#endif

-	cmp	$(VEC_SIZE * 2), %RDX_LP

-	ja	L(more_2x_vec)

-	/* From VEC and to 2 * VEC.  No branch when size == VEC_SIZE.  */

-	VMOVU	%VEC(0), (%rdi)

-	VMOVU	%VEC(0), (VEC_SIZE * -1)(%rdi, %rdx)

-	VZEROUPPER_RETURN

-END (BZERO_SYMBOL(__bzero, unaligned))

-

 #if defined SHARED && IS_IN (libc)

 ENTRY_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))

 	cmp	%RDX_LP, %RCX_LP

@@ -216,31 +187,6 @@ END (__memset_erms)

 END (MEMSET_SYMBOL (__memset, erms))

 # endif

-ENTRY_P2ALIGN (BZERO_SYMBOL(__bzero, unaligned_erms), 6)

-# if VEC_SIZE > 16

-	BZERO_ZERO_VEC0 ()

-# endif

-	mov	%RDI_LP, %RAX_LP

-	mov	%RSI_LP, %RDX_LP

-# ifndef USE_LESS_VEC_MASK_STORE

-	xorl	%esi, %esi

-# endif

-	cmp	$VEC_SIZE, %RDX_LP

-	jb	L(less_vec_no_vdup)

-# ifdef USE_LESS_VEC_MASK_STORE

-	xorl	%esi, %esi

-# endif

-# if VEC_SIZE <= 16

-	BZERO_ZERO_VEC0 ()

-# endif

-	cmp	$(VEC_SIZE * 2), %RDX_LP

-	ja	L(stosb_more_2x_vec)

-	/* From VEC and to 2 * VEC.  No branch when size == VEC_SIZE.  */

-	VMOVU	%VEC(0), (%rdi)

-	VMOVU	%VEC(0), (VEC_SIZE * -1)(%rdi, %rdx)

-	VZEROUPPER_RETURN

-END (BZERO_SYMBOL(__bzero, unaligned_erms))

-

 # if defined SHARED && IS_IN (libc)

 ENTRY_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned_erms))

 	cmp	%RDX_LP, %RCX_LP

@@ -282,7 +228,6 @@ L(last_2x_vec):

 #ifdef USE_LESS_VEC_MASK_STORE

 	.p2align 4,, 10

 L(less_vec):

-L(less_vec_no_vdup):

 L(less_vec_from_wmemset):

 	/* Less than 1 VEC.  */

 # if VEC_SIZE != 16 && VEC_SIZE != 32 && VEC_SIZE != 64

@@ -430,9 +375,6 @@ L(less_vec):

 	   xmm). This is only does anything for AVX2.  */

 	MEMSET_VDUP_TO_VEC0_LOW ()

 L(less_vec_from_wmemset):

-#if VEC_SIZE > 16

-L(less_vec_no_vdup):

-#endif

 #endif

 L(cross_page):

 #if VEC_SIZE > 32

@@ -445,9 +387,6 @@ L(cross_page):

 #endif

 #ifndef USE_XMM_LESS_VEC

 	MOVQ	%XMM0, %SET_REG64

-#endif

-#if VEC_SIZE <= 16

-L(less_vec_no_vdup):

 #endif

 	cmpl	$8, %edx

 	jge	L(between_8_15)