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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2022-05-13 09:33:30 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2022-05-16 09:36:06 -0300
commit9403b71ae97e3f1a91c796ddcbb4e6f044434734 (patch)
tree7a36c6a109815737ff5700d55125042bd2d0951e /sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms-rtm.S
parent7b1cfba79ee54221ffa7d7879433b7ee1728cd76 (diff)
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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.
Diffstat (limited to 'sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms-rtm.S')
-rw-r--r--sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms-rtm.S1
1 files changed, 0 insertions, 1 deletions
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 5a5ee6f672..8ac3e479bb 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"