From 66bf7c8f7194ecd3b9f6426ca3b4807e8a8996a2 Mon Sep 17 00:00:00 2001
From: Eric Fiselier <eric@efcs.ca>
Date: Thu, 12 Mar 2015 20:27:29 -0400
Subject: [PATCH] add floating point comparison warnings

---
 CMakeLists.txt         |  1 +
 src/benchmark.cc       |  4 ++--
 src/stat.h             | 15 ++++++++++-----
 test/benchmark_test.cc |  2 +-
 test/filter_test.cc    |  8 ++++----
 5 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b4a36bd9..947239bc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -39,6 +39,7 @@ add_cxx_compiler_flag(-Wshadow)
 add_cxx_compiler_flag(-Werror)
 add_cxx_compiler_flag(-pedantic-errors)
 add_cxx_compiler_flag(-Wshorten-64-to-32)
+add_cxx_compiler_flag(-Wfloat-equal)
 # TODO(ericwf): enable this for g++
 #add_cxx_compiler_flag(-Wzero-as-null-pointer-constant)
 # Release flags
diff --git a/src/benchmark.cc b/src/benchmark.cc
index 8b0682e6..78eda597 100644
--- a/src/benchmark.cc
+++ b/src/benchmark.cc
@@ -665,11 +665,11 @@ void RunBenchmark(const benchmark::internal::Benchmark::Instance& b,
           (seconds >= FLAGS_benchmark_min_time) ||
           (real_accumulated_time >= 5*FLAGS_benchmark_min_time)) {
         double bytes_per_second = 0;
-        if (total.bytes_processed > 0 && seconds != 0.0) {
+        if (total.bytes_processed > 0 && seconds > 0.0) {
           bytes_per_second = (total.bytes_processed / seconds);
         }
         double items_per_second = 0;
-        if (total.items_processed > 0 && seconds != 0.0) {
+        if (total.items_processed > 0 && seconds > 0.0) {
           items_per_second = (total.items_processed / seconds);
         }
 
diff --git a/src/stat.h b/src/stat.h
index 435743c6..c4ecfe8e 100644
--- a/src/stat.h
+++ b/src/stat.h
@@ -2,8 +2,10 @@
 #define BENCHMARK_STAT_H_
 
 #include <cmath>
-#include <ostream>
 #include <limits>
+#include <ostream>
+#include <type_traits>
+
 
 namespace benchmark {
 
@@ -13,10 +15,10 @@ class Stat1;
 template <typename VType, typename NumType>
 class Stat1MinMax;
 
-typedef Stat1<float, float> Stat1_f;
-typedef Stat1<double, double> Stat1_d;
-typedef Stat1MinMax<float, float> Stat1MinMax_f;
-typedef Stat1MinMax<double, double> Stat1MinMax_d;
+typedef Stat1<float, int64_t> Stat1_f;
+typedef Stat1<double, int64_t> Stat1_d;
+typedef Stat1MinMax<float, int64_t> Stat1MinMax_f;
+typedef Stat1MinMax<double, int64_t> Stat1MinMax_d;
 
 template <typename VType>
 class Vector2;
@@ -133,6 +135,9 @@ class Stat1 {
   }
 
  private:
+  static_assert(std::is_integral<NumType>::value &&
+                !std::is_same<NumType, bool>::value,
+                "NumType must be an integral type that is not bool.");
   // Let i be the index of the samples provided (using +=)
   // and weight[i],value[i] be the data of sample #i
   // then the variables have the following meaning:
diff --git a/test/benchmark_test.cc b/test/benchmark_test.cc
index d44ea319..dd009af1 100644
--- a/test/benchmark_test.cc
+++ b/test/benchmark_test.cc
@@ -158,7 +158,7 @@ static void BM_LongTest(benchmark::State& state) {
   while (state.KeepRunning())
     for (int i = 0; i < state.range_x(); ++i)
       tracker += i;
-  assert(tracker != 0.0);
+  assert(tracker > 1.0);
 }
 BENCHMARK(BM_LongTest)->Range(1<<16,1<<28);
 
diff --git a/test/filter_test.cc b/test/filter_test.cc
index 00c29553..c7258acf 100644
--- a/test/filter_test.cc
+++ b/test/filter_test.cc
@@ -1,8 +1,8 @@
 #include "benchmark/benchmark.h"
 
-#include <assert.h>
-#include <math.h>
-#include <stdint.h>
+#include <cassert>
+#include <cmath>
+#include <cstdint>
 
 #include <iostream>
 #include <sstream>
@@ -69,7 +69,7 @@ BENCHMARK(BM_CalculatePi)->ThreadPerCpu();
 int main(int argc, const char* argv[]) {
   benchmark::Initialize(&argc, argv);
 
-  assert(CalculatePi(1) == 0.0);
+  assert(std::fabs(CalculatePi(1)) < 0.001);
 
   TestReporter test_reporter;
   benchmark::RunSpecifiedBenchmarks(&test_reporter);