From d02d04a18f300ebe97319ca6e91fc943cb14f58b Mon Sep 17 00:00:00 2001
From: "Ronald S. Bultje" <rsbultje@gmail.com>
Date: Wed, 22 Apr 2015 14:53:01 -0400
Subject: [PATCH] vp9: remove one optimization branch in iadst16 which causes
overflows.
See sample vp90-2-14-resize-fp-tiles-16-8-4-2-1.webm from the vp9 test
vector set which reproduces the issue. This probably costs a few cycles,
but I don't think there's an easy way to workaround that.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
libavcodec/x86/vp9itxfm.asm | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/libavcodec/x86/vp9itxfm.asm b/libavcodec/x86/vp9itxfm.asm
index bfe427fa703..a9d45a4b46f 100644
--- a/libavcodec/x86/vp9itxfm.asm
+++ b/libavcodec/x86/vp9itxfm.asm
@@ -1699,7 +1699,9 @@ VP9_IDCT_IDCT_16x16_ADD_XMM avx
SUMSUB_BA w, 5, 7, 4
PSIGNW m5, [pw_m1] ; m12=out15[w], m8=t3[w]
-%if cpuflag(ssse3)
+ ; unfortunately, the code below overflows in some cases, e.g.
+ ; http://downloads.webmproject.org/test_data/libvpx/vp90-2-14-resize-fp-tiles-16-8-4-2-1.webm
+%if 0 ; cpuflag(ssse3)
SUMSUB_BA w, 7, 6, 4
pmulhrsw m7, [pw_m11585x2] ; m8=out7[w]
pmulhrsw m6, [pw_11585x2] ; m1=out8[w]
--
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