Revert "Revert "Use compiler builtins for fabs.""

Don't enable the inlines when building libm itself. Otherwise clang gets
upset by seeing both an inline and a non-inline definition.

This reverts commit c5deb0f883cbdca7e5ab75f92f82c31d21367f49.

Change-Id: If7abdb351f5a5549d6a331b33af408e8fcfa9868

1 files changed, 26 insertions, 0 deletions

diff --git a/benchmarks/math_benchmark.cpp b/benchmarks/math_benchmark.cpp
index 2e0c962..ed5b56c 100644
--- a/benchmarks/math_benchmark.cpp
+++ b/benchmarks/math_benchmark.cpp
@@ -258,3 +258,29 @@ void BM_math_signbit::Run(int iters, double value) {
 
   StopBenchmarkTiming();
 }
+
+BENCHMARK_WITH_ARG(BM_math_fabs_macro, double)->AT_COMMON_VALS;
+void BM_math_fabs_macro::Run(int iters, double value) {
+  StartBenchmarkTiming();
+
+  d = 0.0;
+  v = value;
+  for (int i = 0; i < iters; ++i) {
+    d += fabs(v);
+  }
+
+  StopBenchmarkTiming();
+}
+
+BENCHMARK_WITH_ARG(BM_math_fabs, double)->AT_COMMON_VALS;
+void BM_math_fabs::Run(int iters, double value) {
+  StartBenchmarkTiming();
+
+  d = 0.0;
+  v = value;
+  for (int i = 0; i < iters; ++i) {
+    d += (fabs)(v);
+  }
+
+  StopBenchmarkTiming();
+}