1 /*
2 * Copyright (C) 2023 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <limits>
18
19 #include "gtest/gtest.h"
20
21 constexpr int kNumIterations = 1e8;
22
TEST(FPPerf,Adds)23 TEST(FPPerf, Adds) {
24 double x = 0.0;
25 for (int i = 0; i < kNumIterations; i++) {
26 x += 3.14159265359;
27 }
28 EXPECT_NEAR(x, 3.14159265359 * kNumIterations, static_cast<double>(kNumIterations) / 1e8);
29 }
30
TEST(FPPerf,TinyAdds)31 TEST(FPPerf, TinyAdds) {
32 double x = 0.0;
33 for (int i = 0; i < kNumIterations; i++) {
34 x += std::numeric_limits<double>::min();
35 }
36 EXPECT_DOUBLE_EQ(x, std::numeric_limits<double>::min() * kNumIterations);
37 }
38
TEST(FPPerf,OverflowingAdds)39 TEST(FPPerf, OverflowingAdds) {
40 double x = 1.0e308;
41 for (int i = 0; i < kNumIterations; i++) {
42 x += x;
43 }
44 EXPECT_EQ(x, std::numeric_limits<double>::infinity());
45 }
46
TEST(FPPerf,OverflowingMuls)47 TEST(FPPerf, OverflowingMuls) {
48 double x = 1.0e308;
49 for (int i = 0; i < kNumIterations; i++) {
50 x *= 3.14159265359;
51 }
52 EXPECT_EQ(x, std::numeric_limits<double>::infinity());
53 }
54
TEST(FPPerf,UnderflowingMuls)55 TEST(FPPerf, UnderflowingMuls) {
56 volatile double x = 1.0e-307;
57 for (int i = 0; i < kNumIterations; i++) {
58 x *= 0.0314159265359;
59 }
60 EXPECT_EQ(x, 0.0);
61 }
62