From x86inc:
> On AMD cpus <=K10, an ordinary ret is slow if it immediately follows either
> a branch or a branch target. So switch to a 2-byte form of ret in that case.
> We can automatically detect "follows a branch", but not a branch target.
> (SSSE3 is a sufficient condition to know that your cpu doesn't have this problem.)
x86inc can automatically determine whether to use REP_RET rather than
REP in most of these cases, so impact is minimal. Additionally, a few
REP_RETs were used unnecessary, despite the return being nowhere near a
branch.
The only CPUs affected were AMD K10s, made between 2007 and 2011, 16
years ago and 12 years ago, respectively.
In the future, everyone involved with x86inc should consider dropping
REP_RETs altogether.
Otherwise nasm writes the full host-specific paths into .o
output, which breaks binary reproducibility.
Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
* commit '502ab21af0ca68f76d6112722c46d2f35c004053':
x86: lpc: simd av_update_lls
The versions are bumped due to changes in lls.h which is used across
libraries affecting intra library ABI
(This version bump also covers changes to lls.h in the immedeatly previous
commits)
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Lynne
Alexander Kanavin
Ganesh Ajjanagadde
Michael Niedermayer
Loren Merritt
Loren Merritt