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
  15 using namespace llvm;
  16
  17 namespace {
  18
  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
  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
  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
  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
  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
  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
  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
  96 TEST(BlockFrequency, Divide) {
  97   BlockFrequency Freq(0x3333333333333333ULL);
  98   Freq /= BranchProbability(1, 2);
  99   EXPECT_EQ(Freq.getFrequency(), 0x6666666666666666ULL);
 100 }
 101
 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
 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 }