From 5c15cb138eb1292bc16e64d3cb39953f1c09ce97 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9mi=20Denis-Courmont?= Date: Mon, 19 Sep 2022 19:10:44 +0300 Subject: [PATCH] lavc/vorbisdec: use intermediate variables The compiler cannot infer that the two float vectors do not alias, causing unnecessary extra loads and serialisation. This patch caches the two input values in local variables so that compiler can optimise individual loop iterations. --- libavcodec/vorbisdec.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/libavcodec/vorbisdec.c b/libavcodec/vorbisdec.c index 10d187b82a..72b8e8e15b 100644 --- a/libavcodec/vorbisdec.c +++ b/libavcodec/vorbisdec.c @@ -1581,22 +1581,22 @@ static inline int vorbis_residue_decode(vorbis_context *vc, vorbis_residue *vr, void ff_vorbis_inverse_coupling(float *mag, float *ang, ptrdiff_t blocksize) { - for (ptrdiff_t i = 0; i < blocksize; i++) { - if (mag[i] > 0.0) { - if (ang[i] > 0.0) { - ang[i] = mag[i] - ang[i]; + for (ptrdiff_t i = 0; i < blocksize; i++) { + float angi = ang[i], magi = mag[i]; + + if (magi > 0.f) { + if (angi > 0.f) { + ang[i] = magi - angi; } else { - float temp = ang[i]; - ang[i] = mag[i]; - mag[i] += temp; + ang[i] = magi; + mag[i] = magi + angi; } } else { - if (ang[i] > 0.0) { - ang[i] += mag[i]; + if (angi > 0.f) { + ang[i] = magi + angi; } else { - float temp = ang[i]; - ang[i] = mag[i]; - mag[i] -= temp; + ang[i] = magi; + mag[i] = magi - angi; } } }