From 0618cbc98994ac850c47b926ff6ff73456f9f793 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Per=20=C3=85hgren?= <peah@webrtc.org>
Date: Thu, 13 Feb 2020 21:08:54 +0100
Subject: [PATCH] AEC3: Avoid heap-allocations in sums of the values in nested
 vectors
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This CL avoids the head-allocations done in a sum of the squared values
in a nested vector.

Bug: webrtc:11361, chromium:1052086
Change-Id: I698b855bdd54df2147ef3b6d5e3d401401228d76
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/168543
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30520}
---
 modules/audio_processing/aec3/suppression_gain.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/modules/audio_processing/aec3/suppression_gain.cc b/modules/audio_processing/aec3/suppression_gain.cc
index ea7af505e0..c1f12b7748 100644
--- a/modules/audio_processing/aec3/suppression_gain.cc
+++ b/modules/audio_processing/aec3/suppression_gain.cc
@@ -390,8 +390,8 @@ bool SuppressionGain::LowNoiseRenderDetector::Detect(
     const std::vector<std::vector<std::vector<float>>>& render) {
   float x2_sum = 0.f;
   float x2_max = 0.f;
-  for (auto x_ch : render[0]) {
-    for (auto x_k : x_ch) {
+  for (const auto& x_ch : render[0]) {
+    for (const auto& x_k : x_ch) {
       const float x2 = x_k * x_k;
       x2_sum += x2;
       x2_max = std::max(x2_max, x2);