[llvm-profdata] Add SaturatingAdd/SaturatingMultiply Helper Functions (2nd try)

Summary:
This change adds MathExtras helper functions for handling unsigned, saturating addition and multiplication. It also updates the instrumentation and sample profile merge implementations to use them.

Reviewers: dnovillo, bogner, davidxl

Subscribers: davidxl, llvm-commits

Differential Revision: http://reviews.llvm.org/D14720

llvm-svn: 253497

1 files changed, 36 insertions, 0 deletions

diff --git a/llvm/unittests/Support/MathExtrasTest.cpp b/llvm/unittests/Support/MathExtrasTest.cpp
index 8bd47e3..781bce3 100644
--- a/llvm/unittests/Support/MathExtrasTest.cpp
+++ b/llvm/unittests/Support/MathExtrasTest.cpp
@@ -190,4 +190,40 @@ TEST(MathExtras, RoundUpToAlignment) {
   EXPECT_EQ(552u, RoundUpToAlignment(321, 255, 42));
 }
 
+template<typename T>
+void SaturatingAddTestHelper()
+{
+  const T Max = std::numeric_limits<T>::max();
+  EXPECT_EQ(T(3), SaturatingAdd(T(1), T(2)));
+  EXPECT_EQ(Max, SaturatingAdd(Max, T(1)));
+  EXPECT_EQ(Max, SaturatingAdd(T(1), Max));
+  EXPECT_EQ(Max, SaturatingAdd(Max, Max));
+}
+
+TEST(MathExtras, SaturatingAdd) {
+  SaturatingAddTestHelper<uint8_t>();
+  SaturatingAddTestHelper<uint16_t>();
+  SaturatingAddTestHelper<uint32_t>();
+  SaturatingAddTestHelper<uint64_t>();
+}
+
+template<typename T>
+void SaturatingMultiplyTestHelper()
+{
+  const T Max = std::numeric_limits<T>::max();
+  EXPECT_EQ(T(0), SaturatingMultiply(T(1), T(0)));
+  EXPECT_EQ(T(0), SaturatingMultiply(T(0), T(1)));
+  EXPECT_EQ(T(6), SaturatingMultiply(T(2), T(3)));
+  EXPECT_EQ(Max, SaturatingMultiply(Max, T(2)));
+  EXPECT_EQ(Max, SaturatingMultiply(T(2),Max));
+  EXPECT_EQ(Max, SaturatingMultiply(Max, Max));
+}
+
+TEST(MathExtras, SaturatingMultiply) {
+  SaturatingMultiplyTestHelper<uint8_t>();
+  SaturatingMultiplyTestHelper<uint16_t>();
+  SaturatingMultiplyTestHelper<uint32_t>();
+  SaturatingMultiplyTestHelper<uint64_t>();
+}
+
 }