Re: [FFmpeg-devel] [PATCH 1/2] lavu/bswap: remove some inline assembler

[Michael Niedermayer <michael@niedermayer.cc>]

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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

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