glibc/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
Adhemerval Zanella 9403b71ae9 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.
2022-05-16 09:36:06 -03:00

39 lines
886 B
ArmAsm

#if IS_IN (libc)
# define USE_WITH_AVX2 1
# define VEC_SIZE 32
# define MOV_SIZE 4
# define RET_SIZE 4
# define VEC(i) ymm##i
# define VMOVU vmovdqu
# define VMOVA vmovdqa
# define MEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
vmovd d, %xmm0; \
movq r, %rax;
# define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
MEMSET_SET_VEC0_AND_SET_RETURN(d, r)
# define MEMSET_VDUP_TO_VEC0_HIGH() vpbroadcastb %xmm0, %ymm0
# define MEMSET_VDUP_TO_VEC0_LOW() vpbroadcastb %xmm0, %xmm0
# define WMEMSET_VDUP_TO_VEC0_HIGH() vpbroadcastd %xmm0, %ymm0
# define WMEMSET_VDUP_TO_VEC0_LOW() vpbroadcastd %xmm0, %xmm0
# ifndef SECTION
# define SECTION(p) p##.avx
# endif
# ifndef MEMSET_SYMBOL
# define MEMSET_SYMBOL(p,s) p##_avx2_##s
# endif
# ifndef WMEMSET_SYMBOL
# define WMEMSET_SYMBOL(p,s) p##_avx2_##s
# endif
# define USE_XMM_LESS_VEC
# include "memset-vec-unaligned-erms.S"
#endif