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.
It is overridden by ff_add_bytes_l2_sse2() on any non-ancient CPU.
Reviewed-by: Henrik Gramner <henrik@gramner.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
The .text section is already 16-byte aligned by default on all supported
platforms so `SECTION_TEXT` isn't any different from `SECTION .text`.
Signed-off-by: Anton Khirnov <anton@khirnov.net>
This fixes artifacts in the last pixel of rows with some widths and pixel formats
Found-by: Dominique Leroux <Dominique.Leroux@autodesk.com>
Tested-by: Dominique Leroux <Dominique.Leroux@autodesk.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
For test images manually generated to contain only up prediction,
timing results:
8380x3032 255x185
before: 138635 1992
after: 139232 1996
Actually jumping to the proper version depending on the alignment:
8380x3032: 138767
A 0.5% speed improvement for gigantic images is not worth the code
duplication.
Fixes ticket #4148
Line sizes are only 8-byte aligned, so use unaliged loads
for add_bytes_l2 pointers.
Increasing the alignment requirement to 16 seemed a bit extreme
(png may be used for rather small sizes).
Also fix a mov that had its arguments swapped, leading
add_bytes_l2 being applied on up to 8 bytes too few.
Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>