[FFmpeg-devel] [PATCH 1/2] lavu/bswap: remove some inline assembler
Michael Niedermayer
michael at niedermayer.cc
Tue Jun 11 18:57:21 EEST 2024
On Tue, Jun 11, 2024 at 12:38:37PM -0300, James Almer wrote:
> On 6/11/2024 10:15 AM, Michael Niedermayer wrote:
> > On Fri, Jun 07, 2024 at 09:19:46PM +0300, Rémi Denis-Courmont wrote:
> > > C code or compiler built-ins are preferable over inline assembler for
> > > byte-swaps as it allows for better optimisations (e.g. instruction
> > > scheduling) which would otherwise be impossible.
> > >
> > > As with f64c2e710fa1a7b59753224e717f57c48462076f for x86 and Arm,
> > > this removes the inline assembler on GCC (and Clang) since we now
> > > require recent enough compiler versions (this indeed seems to work on
> > > AArch64).
> > > ---
> > > libavutil/aarch64/bswap.h | 56 ---------------------------------------
> > > libavutil/avr32/bswap.h | 44 ------------------------------
> > > libavutil/bswap.h | 8 +-----
> > > libavutil/sh4/bswap.h | 48 ---------------------------------
> >
> > As you are writing that this preferrable for better optimisations
> > Please provide benchmarks (for sh4, avr32)
>
> This is a ridiculous request, considering nobody has such hardware at all.
Then I think its a ridiculous claim that this optimizes the code
I mean, at some point there was hardware and these optimisations did improve
speed.
This patch is not removing the code because its a rare (or dead) platform, it removes
it with the claim that this would "allows for better optimisations"
Iam sorry but i do not see why asking for the claim in the commit message
to be backed up with facts being ridiculous
The claim in the commit message may be ridiculous
thx
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
No great genius has ever existed without some touch of madness. -- Aristotle
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 195 bytes
Desc: not available
URL: <https://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20240611/64bbf78c/attachment.sig>
More information about the ffmpeg-devel
mailing list