llvm/unittests/Support/BlockFrequencyTest.cpp

   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 #include <cstdint>
  15
  16 using namespace llvm;
  17
  18 namespace {
  19
  20 TEST(BlockFrequencyTest, OneToZero) {
  21   BlockFrequency Freq(1);
  22   BranchProbability Prob(UINT32_MAX / 3, UINT32_MAX);
  23   Freq *= Prob;
  24   EXPECT_EQ(Freq.getFrequency(), 0u);
  25
  26   Freq = BlockFrequency(1);
  27   Freq *= Prob;
  28   EXPECT_EQ(Freq.getFrequency(), 0u);
  29 }
  30
  31 TEST(BlockFrequencyTest, OneToOne) {
  32   BlockFrequency Freq(1);
  33   BranchProbability Prob(UINT32_MAX, UINT32_MAX);
  34   Freq *= Prob;
  35   EXPECT_EQ(Freq.getFrequency(), 1u);
  36
  37   Freq = BlockFrequency(1);
  38   Freq *= Prob;
  39   EXPECT_EQ(Freq.getFrequency(), 1u);
  40 }
  41
  42 TEST(BlockFrequencyTest, ThreeToOne) {
  43   BlockFrequency Freq(3);
  44   BranchProbability Prob(3000000, 9000000);
  45   Freq *= Prob;
  46   EXPECT_EQ(Freq.getFrequency(), 1u);
  47
  48   Freq = BlockFrequency(3);
  49   Freq *= Prob;
  50   EXPECT_EQ(Freq.getFrequency(), 1u);
  51 }
  52
  53 TEST(BlockFrequencyTest, MaxToHalfMax) {
  54   BlockFrequency Freq(UINT64_MAX);
  55   BranchProbability Prob(UINT32_MAX / 2, UINT32_MAX);
  56   Freq *= Prob;
  57   EXPECT_EQ(Freq.getFrequency(), 9223372036854775807ULL);
  58
  59   Freq = BlockFrequency(UINT64_MAX);
  60   Freq *= Prob;
  61   EXPECT_EQ(Freq.getFrequency(), 9223372036854775807ULL);
  62 }
  63
  64 TEST(BlockFrequencyTest, BigToBig) {
  65   const uint64_t Big = 387246523487234346LL;
  66   const uint32_t P = 123456789;
  67   BlockFrequency Freq(Big);
  68   BranchProbability Prob(P, P);
  69   Freq *= Prob;
  70   EXPECT_EQ(Freq.getFrequency(), Big);
  71
  72   Freq = BlockFrequency(Big);
  73   Freq *= Prob;
  74   EXPECT_EQ(Freq.getFrequency(), Big);
  75 }
  76
  77 TEST(BlockFrequencyTest, MaxToMax) {
  78   BlockFrequency Freq(UINT64_MAX);
  79   BranchProbability Prob(UINT32_MAX, UINT32_MAX);
  80   Freq *= Prob;
  81   EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
  82
  83   // This additionally makes sure if we have a value equal to our saturating
  84   // value, we do not signal saturation if the result equals said value, but
  85   // saturating does not occur.
  86   Freq = BlockFrequency(UINT64_MAX);
  87   Freq *= Prob;
  88   EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
  89 }
  90
  91 TEST(BlockFrequencyTest, Subtract) {
  92   BlockFrequency Freq1(0), Freq2(1);
  93   EXPECT_EQ((Freq1 - Freq2).getFrequency(), 0u);
  94   EXPECT_EQ((Freq2 - Freq1).getFrequency(), 1u);
  95 }
  96
  97 TEST(BlockFrequency, Divide) {
  98   BlockFrequency Freq(0x3333333333333333ULL);
  99   Freq /= BranchProbability(1, 2);
 100   EXPECT_EQ(Freq.getFrequency(), 0x6666666666666666ULL);
 101 }
 102
 103 TEST(BlockFrequencyTest, Saturate) {
 104   BlockFrequency Freq(0x3333333333333333ULL);
 105   Freq /= BranchProbability(100, 300);
 106   EXPECT_EQ(Freq.getFrequency(), 0x9999999866666668ULL);
 107   Freq /= BranchProbability(1, 2);
 108   EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
 109
 110   Freq = BlockFrequency(UINT64_C(0x1000000000000000));
 111   Freq /= BranchProbability(10000, 170000);
 112   EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
 113
 114   // Try to cheat the multiplication overflow check.
 115   Freq = BlockFrequency(UINT64_C(0x00000001f0000001));
 116   Freq /= BranchProbability(1000, 0xf000000f);
 117   EXPECT_EQ(33527736066704712ULL, Freq.getFrequency());
 118 }
 119
 120 TEST(BlockFrequencyTest, SaturatingRightShift) {
 121   BlockFrequency Freq(0x10080ULL);
 122   Freq >>= 2;
 123   EXPECT_EQ(Freq.getFrequency(), 0x4020ULL);
 124   Freq >>= 20;
 125   EXPECT_EQ(Freq.getFrequency(), 0x1ULL);
 126 }
 127
 128 }