On 1/11/20 4:02 PM, Shawn Landden wrote: > --- > man3/memcmp.3 | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/man3/memcmp.3 b/man3/memcmp.3 > index 247eed223..6afca5ea4 100644 > --- a/man3/memcmp.3 > +++ b/man3/memcmp.3 > @@ -84,10 +84,17 @@ because the required CPU time depends on the number of equal bytes. > Instead, a function that performs comparisons in constant time is required. > Some operating systems provide such a function (e.g., NetBSD's > .BR consttime_memequal ()), > but no such function is specified in POSIX. > On Linux, it may be necessary to implement such a function oneself. > +.PP > +LLVM 9, released in 2019, and later will optimize a call > +.BR memcmp () > +to a call to > +.BR bcmp (3) > +if the return value is only checked for equilivence to zero. > +.\" http://releases.llvm.org/9.0.0/docs/ReleaseNotes.html#noteworthy-optimizations See my othermail. Wht is it relevant to document this compiler-specific detail? Thanks, Michael > .SH SEE ALSO > .BR bcmp (3), > .BR bstring (3), > .BR strcasecmp (3), > .BR strcmp (3), > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
