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vp9: remove one optimization branch in iadst16 which causes overflows.

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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>
This commit is contained in:
Ronald S. Bultje 2015-04-22 14:53:01 -04:00 committed by Michael Niedermayer
parent 86d00ede4f
commit d02d04a18f
1 changed files with 3 additions and 1 deletions
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4
libavcodec/x86/vp9itxfm.asm
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@ -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]