From a018e677f247ac2d06618d4f4a79b7a5e733a21a Mon Sep 17 00:00:00 2001 From: cschuldt Date: Mon, 22 Nov 2021 17:59:36 +0100 Subject: [PATCH] Optimize block_delay_buffer. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Reducing pointer following. This will allow the compiler to optimize more efficiently with the "-fno-strict-aliasing" flag. Bug: None Change-Id: Ic126bd2d53969a7e9d15e1c1081d5278e27a816c Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/238664 Reviewed-by: Per Åhgren Reviewed-by: Ivo Creusen Commit-Queue: Christian Schuldt Cr-Commit-Position: refs/heads/main@{#35414} --- .../audio_processing/aec3/block_delay_buffer.cc | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/modules/audio_processing/aec3/block_delay_buffer.cc b/modules/audio_processing/aec3/block_delay_buffer.cc index b9eb3c9f93..059bbafcdb 100644 --- a/modules/audio_processing/aec3/block_delay_buffer.cc +++ b/modules/audio_processing/aec3/block_delay_buffer.cc @@ -41,17 +41,24 @@ void BlockDelayBuffer::DelaySignal(AudioBuffer* frame) { RTC_DCHECK_EQ(buf_[ch].size(), frame->num_bands()); RTC_DCHECK_EQ(buf_[ch].size(), num_bands); rtc::ArrayView frame_ch(frame->split_bands(ch), num_bands); + const size_t delay = delay_; for (size_t band = 0; band < num_bands; ++band) { RTC_DCHECK_EQ(delay_, buf_[ch][band].size()); i = i_start; - for (size_t k = 0; k < frame_length_; ++k) { - const float tmp = buf_[ch][band][i]; - buf_[ch][band][i] = frame_ch[band][k]; - frame_ch[band][k] = tmp; + // Offloading these pointers and class variables to local variables allows + // the compiler to optimize the below loop when compiling with + // '-fno-strict-aliasing'. + float* buf_ch_band = buf_[ch][band].data(); + float* frame_ch_band = frame_ch[band]; - i = i < delay_ - 1 ? i + 1 : 0; + for (size_t k = 0, frame_length = frame_length_; k < frame_length; ++k) { + const float tmp = buf_ch_band[i]; + buf_ch_band[i] = frame_ch_band[k]; + frame_ch_band[k] = tmp; + + i = i < delay - 1 ? i + 1 : 0; } } }