diff options
| author | H.J. Lu <hjl.tools@gmail.com> | 2017-06-27 07:55:00 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2017-06-27 07:55:00 -0700 |
| commit | e94c31035739b693c3699b3c4cad0206631fbee7 (patch) | |
| tree | b0666d325944a10e78d4dd6333c19c108c50d74c /sysdeps/unix | |
| parent | 6980be7cbf4f108a4936ac64242f58340d56c806 (diff) | |
| download | glibc-e94c31035739b693c3699b3c4cad0206631fbee7.tar.gz glibc-e94c31035739b693c3699b3c4cad0206631fbee7.tar.xz glibc-e94c31035739b693c3699b3c4cad0206631fbee7.zip | |
x86-64: Optimize memcmp-avx2-movbe.S for short difference
Check the first 32 bytes before checking size when size >= 32 bytes to avoid unnecessary branch if the difference is in the first 32 bytes. Replace vpmovmskb/subl/jnz with vptest/jnc. On Haswell, the new version is as fast as the previous one. On Skylake, the new version is a little bit faster. * sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S (MEMCMP): Check the first 32 bytes before checking size when size >= 32 bytes. Replace vpmovmskb/subl/jnz with vptest/jnc.
Diffstat (limited to 'sysdeps/unix')
0 files changed, 0 insertions, 0 deletions