src/llvm/unittests/Support/BlockFrequencyTest.cpp

   1 #include "llvm/Support/BlockFrequency.h"
   2 #include "llvm/Support/BranchProbability.h"
   3 #include "llvm/Support/DataTypes.h"
   4 #include "gtest/gtest.h"
   5 #include <climits>
   6
   7 using namespace llvm;
   8
   9 namespace {
  10
  11 TEST(BlockFrequencyTest, OneToZero) {
  12   BlockFrequency Freq(1);
  13   BranchProbability Prob(UINT32_MAX - 1, UINT32_MAX);
  14   Freq *= Prob;
  15   EXPECT_EQ(Freq.getFrequency(), 0u);
  16
  17   Freq = BlockFrequency(1);
  18   Freq *= Prob;
  19   EXPECT_EQ(Freq.getFrequency(), 0u);
  20 }
  21
  22 TEST(BlockFrequencyTest, OneToOne) {
  23   BlockFrequency Freq(1);
  24   BranchProbability Prob(UINT32_MAX, UINT32_MAX);
  25   Freq *= Prob;
  26   EXPECT_EQ(Freq.getFrequency(), 1u);
  27
  28   Freq = BlockFrequency(1);
  29   Freq *= Prob;
  30   EXPECT_EQ(Freq.getFrequency(), 1u);
  31 }
  32
  33 TEST(BlockFrequencyTest, ThreeToOne) {
  34   BlockFrequency Freq(3);
  35   BranchProbability Prob(3000000, 9000000);
  36   Freq *= Prob;
  37   EXPECT_EQ(Freq.getFrequency(), 1u);
  38
  39   Freq = BlockFrequency(3);
  40   Freq *= Prob;
  41   EXPECT_EQ(Freq.getFrequency(), 1u);
  42 }
  43
  44 TEST(BlockFrequencyTest, MaxToHalfMax) {
  45   BlockFrequency Freq(UINT64_MAX);
  46   BranchProbability Prob(UINT32_MAX / 2, UINT32_MAX);
  47   Freq *= Prob;
  48   EXPECT_EQ(Freq.getFrequency(), 9223372034707292159ULL);
  49
  50   Freq = BlockFrequency(UINT64_MAX);
  51   Freq *= Prob;
  52   EXPECT_EQ(Freq.getFrequency(), 9223372034707292159ULL);
  53 }
  54
  55 TEST(BlockFrequencyTest, BigToBig) {
  56   const uint64_t Big = 387246523487234346LL;
  57   const uint32_t P = 123456789;
  58   BlockFrequency Freq(Big);
  59   BranchProbability Prob(P, P);
  60   Freq *= Prob;
  61   EXPECT_EQ(Freq.getFrequency(), Big);
  62
  63   Freq = BlockFrequency(Big);
  64   Freq *= Prob;
  65   EXPECT_EQ(Freq.getFrequency(), Big);
  66 }
  67
  68 TEST(BlockFrequencyTest, MaxToMax) {
  69   BlockFrequency Freq(UINT64_MAX);
  70   BranchProbability Prob(UINT32_MAX, UINT32_MAX);
  71   Freq *= Prob;
  72   EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
  73
  74   // This additionally makes sure if we have a value equal to our saturating
  75   // value, we do not signal saturation if the result equals said value, but
  76   // saturating does not occur.
  77   Freq = BlockFrequency(UINT64_MAX);
  78   Freq *= Prob;
  79   EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
  80 }
  81
  82 TEST(BlockFrequency, Divide) {
  83   BlockFrequency Freq(0x3333333333333333ULL);
  84   Freq /= BranchProbability(1, 2);
  85   EXPECT_EQ(Freq.getFrequency(), 0x6666666666666666ULL);
  86 }
  87
  88 TEST(BlockFrequencyTest, Saturate) {
  89   BlockFrequency Freq(0x3333333333333333ULL);
  90   Freq /= BranchProbability(100, 300);
  91   EXPECT_EQ(Freq.getFrequency(), 0x9999999999999999ULL);
  92   Freq /= BranchProbability(1, 2);
  93   EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
  94
  95   Freq = 0x1000000000000000ULL;
  96   Freq /= BranchProbability(10000, 160000);
  97   EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
  98
  99   // Try to cheat the multiplication overflow check.
 100   Freq = 0x00000001f0000001ull;
 101   Freq /= BranchProbability(1000, 0xf000000f);
 102   EXPECT_EQ(33506781356485509ULL, Freq.getFrequency());
 103 }
 104
 105 TEST(BlockFrequencyTest, SaturatingRightShift) {
 106   BlockFrequency Freq(0x10080ULL);
 107   Freq >>= 2;
 108   EXPECT_EQ(Freq.getFrequency(), 0x4020ULL);
 109   Freq >>= 20;
 110   EXPECT_EQ(Freq.getFrequency(), 0x1ULL);
 111 }
 112
 113 }