On Sat, Jan 30, 2016 at 07:27:22PM +0000, Derek Buitenhuis wrote:
> On 1/30/2016 7:15 PM, Timothy Gu wrote:
> > FATE passes here on a x86-64 machine with both GCC 4.9.2 and 5.3.1.
>
> Perhaps this should be restricted to x86?
Fair enough.
Timothy
>From b75076b5d735005a5a8b25d47c21c38cbaebb30b Mon Sep 17 00:00:00 2001
From: Timothy Gu <timothyg...@gmail.com>
Date: Sat, 30 Jan 2016 10:52:44 -0800
Subject: [PATCH] =?UTF-8?q?configure:=20Enable=20GCC=20vectorization=20on?=
=?UTF-8?q?=20=E2=89=A54.9=20on=20x86?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
4.9 was released precisely nine years after the first GCC version with
autovectorizer (4.0) and six years after the first GCC version with
`-ftree-vectorize` default to enabled on `-O3` (4.3). We've given GCC
enough time to fix those bugs.
FATE passes here on a x86-64 machine with both GCC 4.9.2 and 5.3.1.
Some optimization hotspots benefit greatly from this change, especially
those without handwritten assembly. For instance, the main function in
vf_phase is now 1.6x faster (1.2x overall) on my machine.
---
configure | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/configure b/configure
index 44ecfc8..ea8156f 100755
--- a/configure
+++ b/configure
@@ -5934,7 +5934,11 @@ elif enabled ccc; then
add_cflags -msg_disable nonstandcast
add_cflags -msg_disable unsupieee
elif enabled gcc; then
- check_optflags -fno-tree-vectorize
+ case $gcc_basever in
+ 4.9*) enabled x86 || check_optflags -fno-tree-vectorize ;;
+ 4.*) check_optflags -fno-tree-vectorize ;;
+ *) enabled x86 || check_optflags -fno-tree-vectorize ;;
+ esac
check_cflags -Werror=format-security
check_cflags -Werror=implicit-function-declaration
check_cflags -Werror=missing-prototypes
--
2.1.4
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
