1 //===- unittests/Support/BlockFrequencyTest.cpp - BlockFrequency tests ----===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "llvm/Support/BlockFrequency.h"
10 #include "llvm/Support/BranchProbability.h"
11 #include "llvm/Support/DataTypes.h"
12 #include "gtest/gtest.h"
13 #include <climits>
14
15 using namespace llvm;
16
17 namespace {
18
TEST(BlockFrequencyTest,OneToZero)19 TEST(BlockFrequencyTest, OneToZero) {
20 BlockFrequency Freq(1);
21 BranchProbability Prob(UINT32_MAX / 3, UINT32_MAX);
22 Freq *= Prob;
23 EXPECT_EQ(Freq.getFrequency(), 0u);
24
25 Freq = BlockFrequency(1);
26 Freq *= Prob;
27 EXPECT_EQ(Freq.getFrequency(), 0u);
28 }
29
TEST(BlockFrequencyTest,OneToOne)30 TEST(BlockFrequencyTest, OneToOne) {
31 BlockFrequency Freq(1);
32 BranchProbability Prob(UINT32_MAX, UINT32_MAX);
33 Freq *= Prob;
34 EXPECT_EQ(Freq.getFrequency(), 1u);
35
36 Freq = BlockFrequency(1);
37 Freq *= Prob;
38 EXPECT_EQ(Freq.getFrequency(), 1u);
39 }
40
TEST(BlockFrequencyTest,ThreeToOne)41 TEST(BlockFrequencyTest, ThreeToOne) {
42 BlockFrequency Freq(3);
43 BranchProbability Prob(3000000, 9000000);
44 Freq *= Prob;
45 EXPECT_EQ(Freq.getFrequency(), 1u);
46
47 Freq = BlockFrequency(3);
48 Freq *= Prob;
49 EXPECT_EQ(Freq.getFrequency(), 1u);
50 }
51
TEST(BlockFrequencyTest,MaxToHalfMax)52 TEST(BlockFrequencyTest, MaxToHalfMax) {
53 BlockFrequency Freq(UINT64_MAX);
54 BranchProbability Prob(UINT32_MAX / 2, UINT32_MAX);
55 Freq *= Prob;
56 EXPECT_EQ(Freq.getFrequency(), 9223372036854775807ULL);
57
58 Freq = BlockFrequency(UINT64_MAX);
59 Freq *= Prob;
60 EXPECT_EQ(Freq.getFrequency(), 9223372036854775807ULL);
61 }
62
TEST(BlockFrequencyTest,BigToBig)63 TEST(BlockFrequencyTest, BigToBig) {
64 const uint64_t Big = 387246523487234346LL;
65 const uint32_t P = 123456789;
66 BlockFrequency Freq(Big);
67 BranchProbability Prob(P, P);
68 Freq *= Prob;
69 EXPECT_EQ(Freq.getFrequency(), Big);
70
71 Freq = BlockFrequency(Big);
72 Freq *= Prob;
73 EXPECT_EQ(Freq.getFrequency(), Big);
74 }
75
TEST(BlockFrequencyTest,MaxToMax)76 TEST(BlockFrequencyTest, MaxToMax) {
77 BlockFrequency Freq(UINT64_MAX);
78 BranchProbability Prob(UINT32_MAX, UINT32_MAX);
79 Freq *= Prob;
80 EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
81
82 // This additionally makes sure if we have a value equal to our saturating
83 // value, we do not signal saturation if the result equals said value, but
84 // saturating does not occur.
85 Freq = BlockFrequency(UINT64_MAX);
86 Freq *= Prob;
87 EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
88 }
89
TEST(BlockFrequencyTest,Subtract)90 TEST(BlockFrequencyTest, Subtract) {
91 BlockFrequency Freq1(0), Freq2(1);
92 EXPECT_EQ((Freq1 - Freq2).getFrequency(), 0u);
93 EXPECT_EQ((Freq2 - Freq1).getFrequency(), 1u);
94 }
95
TEST(BlockFrequency,Divide)96 TEST(BlockFrequency, Divide) {
97 BlockFrequency Freq(0x3333333333333333ULL);
98 Freq /= BranchProbability(1, 2);
99 EXPECT_EQ(Freq.getFrequency(), 0x6666666666666666ULL);
100 }
101
TEST(BlockFrequencyTest,Saturate)102 TEST(BlockFrequencyTest, Saturate) {
103 BlockFrequency Freq(0x3333333333333333ULL);
104 Freq /= BranchProbability(100, 300);
105 EXPECT_EQ(Freq.getFrequency(), 0x9999999866666668ULL);
106 Freq /= BranchProbability(1, 2);
107 EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
108
109 Freq = 0x1000000000000000ULL;
110 Freq /= BranchProbability(10000, 170000);
111 EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
112
113 // Try to cheat the multiplication overflow check.
114 Freq = 0x00000001f0000001ull;
115 Freq /= BranchProbability(1000, 0xf000000f);
116 EXPECT_EQ(33527736066704712ULL, Freq.getFrequency());
117 }
118
TEST(BlockFrequencyTest,SaturatingRightShift)119 TEST(BlockFrequencyTest, SaturatingRightShift) {
120 BlockFrequency Freq(0x10080ULL);
121 Freq >>= 2;
122 EXPECT_EQ(Freq.getFrequency(), 0x4020ULL);
123 Freq >>= 20;
124 EXPECT_EQ(Freq.getFrequency(), 0x1ULL);
125 }
126
127 }
128