From 0743814fb852a02ca86b41e4d6def3abfb109bc3 Mon Sep 17 00:00:00 2001
From: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
Date: Mon, 16 Oct 2017 17:00:02 +0200
Subject: [PATCH] aec3: Use fabsf() instead of std::abs() for floats.

We are using <math.h>, not <cmath>. While the latter defines additional
overloads for abs(), including abs(float), they are not guaranteed to be
available in <math.h>.

libc++ ships its own math.h with the additional overloads, and libstdc++ (v6
or later) has a math.h that includes <cmath>, but this is not always
expected to work: for example, GCC 5.x's libstdc++ does not have these
additional overloads and causes the build to fail.

Just use fabsf() from the C standard library directly, as it achieves the
same thing in a more portable fashion.

Bug: None
Change-Id: I805728269b35051edb54126e204eccd2706e3a92
Reviewed-on: https://webrtc-review.googlesource.com/11460
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Commit-Queue: Raphael Kubo da Costa (rakuco) <raphael.kubo.da.costa@intel.com>
Cr-Commit-Position: refs/heads/master@{#20325}
---
 modules/audio_processing/aec3/aec_state.cc | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/modules/audio_processing/aec3/aec_state.cc b/modules/audio_processing/aec3/aec_state.cc
index 14b83e10be..92ad5cf0dd 100644
--- a/modules/audio_processing/aec3/aec_state.cc
+++ b/modules/audio_processing/aec3/aec_state.cc
@@ -11,6 +11,7 @@
 #include "modules/audio_processing/aec3/aec_state.h"
 
 #include <math.h>
+
 #include <numeric>
 #include <vector>
 
@@ -258,9 +259,9 @@ void AecState::EchoAudibility::Update(rtc::ArrayView<const float> x,
   auto result_x = std::minmax_element(x.begin(), x.end());
   auto result_s = std::minmax_element(s.begin(), s.end());
   const float x_abs =
-      std::max(std::abs(*result_x.first), std::abs(*result_x.second));
+      std::max(fabsf(*result_x.first), fabsf(*result_x.second));
   const float s_abs =
-      std::max(std::abs(*result_s.first), std::abs(*result_s.second));
+      std::max(fabsf(*result_s.first), fabsf(*result_s.second));
 
   if (converged_filter) {
     if (x_abs < 20.f) {
@@ -290,7 +291,7 @@ void AecState::EchoAudibility::Update(rtc::ArrayView<const float> x,
 void AecState::EchoAudibility::UpdateWithOutput(rtc::ArrayView<const float> e) {
   const float e_max = *std::max_element(e.begin(), e.end());
   const float e_min = *std::min_element(e.begin(), e.end());
-  const float e_abs = std::max(std::abs(e_max), std::abs(e_min));
+  const float e_abs = std::max(fabsf(e_max), fabsf(e_min));
 
   if (max_nearend_ < e_abs) {
     max_nearend_ = e_abs;