Add a division operator to BlockFrequency.
Allow a BlockFrequency to be divided by a non-zero BranchProbability
with saturating arithmetic. This will be used to compute the frequency
of a loop header given the probability of leaving the loop.
Our long division algorithm already saturates on overflow, so that was a
freebie.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185184 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Support/BlockFrequencyTest.cpp b/unittests/Support/BlockFrequencyTest.cpp
index ff66bc4..4bcddfe 100644
--- a/unittests/Support/BlockFrequencyTest.cpp
+++ b/unittests/Support/BlockFrequencyTest.cpp
@@ -52,6 +52,24 @@
EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
}
+TEST(BlockFrequency, Divide) {
+ BlockFrequency Freq(0x3333333333333333ULL);
+ Freq /= BranchProbability(1, 2);
+ EXPECT_EQ(Freq.getFrequency(), 0x6666666666666666ULL);
+}
+
+TEST(BlockFrequencyTest, Saturate) {
+ BlockFrequency Freq(0x3333333333333333ULL);
+ Freq /= BranchProbability(100, 300);
+ EXPECT_EQ(Freq.getFrequency(), 0x9999999999999999ULL);
+ Freq /= BranchProbability(1, 2);
+ EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
+
+ Freq = 0x1000000000000000ULL;
+ Freq /= BranchProbability(10000, 160000);
+ EXPECT_EQ(Freq.getFrequency(), UINT64_MAX);
+}
+
TEST(BlockFrequencyTest, ProbabilityCompare) {
BranchProbability A(4, 5);
BranchProbability B(4U << 29, 5U << 29);