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authorNoah Goldstein <goldstein.w.n@gmail.com>2021-10-21 15:54:57 -0500
committerNoah Goldstein <goldstein.w.n@gmail.com>2021-10-26 16:51:29 -0500
commit44829b3ddb64e99e37343a0f25b2c082387d31a5 (patch)
treeba9565215210f530296dd4456816fc69f593e542 /sysdeps/s390/memcmp.c
parent8438135d3481853e300e1043cfee3946dadb28b3 (diff)
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String: Add support for __memcmpeq() ABI on all targets
No bug.

This commit adds support for __memcmpeq() as a new ABI for all
targets. In this commit __memcmpeq() is implemented only as an alias
to the corresponding targets memcmp() implementation. __memcmpeq() is
added as a new symbol starting with GLIBC_2.35 and defined in string.h
with comments explaining its behavior. Basic tests that it is callable
and works where added in string/tester.c

As discussed in the proposal "Add new ABI '__memcmpeq()' to libc"
__memcmpeq() is essentially a reserved namespace for bcmp(). The means
is shares the same specifications as memcmp() except the return value
for non-equal byte sequences is any non-zero value. This is less
strict than memcmp()'s return value specification and can be better
optimized when a boolean return is all that is needed.

__memcmpeq() is meant to only be called by compilers if they can prove
that the return value of a memcmp() call is only used for its boolean
value.

All tests in string/tester.c passed. As well build succeeds on
x86_64-linux-gnu target.
Diffstat (limited to 'sysdeps/s390/memcmp.c')
-rw-r--r--sysdeps/s390/memcmp.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/sysdeps/s390/memcmp.c b/sysdeps/s390/memcmp.c
index 0b4e9da717..52c20af772 100644
--- a/sysdeps/s390/memcmp.c
+++ b/sysdeps/s390/memcmp.c
@@ -46,4 +46,5 @@ s390_libc_ifunc_expr (__redirect_memcmp, memcmp,
 		      })
 		      )
 weak_alias (memcmp, bcmp);
+strong_alias (memcmp, __memcmpeq)
 #endif