[FFmpeg-devel] [PATCH] Fix ff_imdct_calc_sse() on gcc-4.6. (original) (raw)

Alex Converse alex.converse
Mon Jan 31 05:37:17 CET 2011

2011/1/30 M?ns Rullg?rd :

Alex Converse <alex.converse at gmail.com> writes:

On Sun, Jan 30, 2011 at 2:13 AM, Reimar D?ffinger <Reimar.Doeffinger at gmx.de> wrote: On Sun, Jan 30, 2011 at 01:22:05AM -0800, Alex Converse wrote:

On Sun, Jan 30, 2011 at 1:08 AM, Alex Converse <alex.converse at gmail.com> wrote: > > Gcc 4.6 only preserves the first value when using a vector with an "m" > constraint. > --- > ?libavcodec/x86/fftsse.c | ? ?4 ++-- > ?1 files changed, 2 insertions(+), 2 deletions(-) > >

oops this generates an extra indirection. Those of you who like to defend inline asm, please step up and make some suggestions. Use what would be your only option (conceptually, not in implementation of course) if you didn't use inline asm: MANGLE and change DECLAREALIGNED to DECLAREASMCONST There's also the option of a gcc bug report, I have some doubts that is a valid optimization (though there are constraints to make gcc load directly into a xmm register, but both that and the current code have needlessly unpredictable performance). The optimisation is valid, the constraint is wrong. With MANGLE this time. From 51a872ff818bbb0071ab1649d104afcea48546c9 Mon Sep 17 00:00:00 2001 From: Alex Converse <alex.converse at gmail.com> Date: Sun, 30 Jan 2011 01:04:41 -0800 Subject: [PATCH 1/2] Fix ffimdctcalcsse() on gcc-4.6. MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="------------1" This is a multi-part message in MIME format. --------------1 Content-Type: text/plain; charset=UTF-8; format=fixed Content-Transfer-Encoding: 8bit Please try to avoid sending attached patches in this format.

What's wrong with this format and how do I make my tools avoid it?

More information about the ffmpeg-devel mailing list