Support: Write ScaledNumbers::getRounded()

Start extracting helper functions out of -block-freq's `UnsignedFloat`
into `Support/ScaledNumber.h` with the eventual goal of moving and
renaming the class to `ScaledNumber`.

The bike shed about names is still being painted, but I'm going with
this for now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211333 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 61 insertions, 0 deletions

diff --git a/unittests/Support/CMakeLists.txt b/unittests/Support/CMakeLists.txt
index c50acdfb8e..08096a4a17 100644
--- a/unittests/Support/CMakeLists.txt
+++ b/unittests/Support/CMakeLists.txt
@@ -29,6 +29,7 @@ add_llvm_unittest(SupportTests
   ProcessTest.cpp
   ProgramTest.cpp
   RegexTest.cpp
+  ScaledNumberTest.cpp
   SourceMgrTest.cpp
   StringPool.cpp
   SwapByteOrderTest.cpp
diff --git a/unittests/Support/ScaledNumberTest.cpp b/unittests/Support/ScaledNumberTest.cpp
new file mode 100644
index 0000000000..1fa54ff81d
--- /dev/null
+++ b/unittests/Support/ScaledNumberTest.cpp
@@ -0,0 +1,60 @@
+//===- llvm/unittest/Support/ScaledNumberTest.cpp - ScaledPair tests -----==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/ScaledNumber.h"
+
+#include "llvm/Support/DataTypes.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using namespace llvm::ScaledNumbers;
+
+namespace {
+
+template <class UIntT> struct ScaledPair {
+  UIntT D;
+  int S;
+  ScaledPair(const std::pair<UIntT, int16_t> &F) : D(F.first), S(F.second) {}
+  ScaledPair(UIntT D, int S) : D(D), S(S) {}
+
+  bool operator==(const ScaledPair<UIntT> &X) const {
+    return D == X.D && S == X.S;
+  }
+};
+template <class UIntT>
+bool operator==(const std::pair<UIntT, int16_t> &L,
+                const ScaledPair<UIntT> &R) {
+  return ScaledPair<UIntT>(L) == R;
+}
+template <class UIntT>
+void PrintTo(const ScaledPair<UIntT> &F, ::std::ostream *os) {
+  *os << F.D << "*2^" << F.S;
+}
+
+typedef ScaledPair<uint32_t> SP32;
+typedef ScaledPair<uint64_t> SP64;
+
+TEST(ScaledNumberHelpersTest, getRounded) {
+  EXPECT_EQ(getRounded<uint32_t>(0, 0, false), SP32(0, 0));
+  EXPECT_EQ(getRounded<uint32_t>(0, 0, true), SP32(1, 0));
+  EXPECT_EQ(getRounded<uint32_t>(20, 21, true), SP32(21, 21));
+  EXPECT_EQ(getRounded<uint32_t>(UINT32_MAX, 0, false), SP32(UINT32_MAX, 0));
+  EXPECT_EQ(getRounded<uint32_t>(UINT32_MAX, 0, true), SP32(1 << 31, 1));
+
+  EXPECT_EQ(getRounded<uint64_t>(0, 0, false), SP64(0, 0));
+  EXPECT_EQ(getRounded<uint64_t>(0, 0, true), SP64(1, 0));
+  EXPECT_EQ(getRounded<uint64_t>(20, 21, true), SP64(21, 21));
+  EXPECT_EQ(getRounded<uint64_t>(UINT32_MAX, 0, false), SP64(UINT32_MAX, 0));
+  EXPECT_EQ(getRounded<uint64_t>(UINT32_MAX, 0, true),
+            SP64(UINT64_C(1) << 32, 0));
+  EXPECT_EQ(getRounded<uint64_t>(UINT64_MAX, 0, false), SP64(UINT64_MAX, 0));
+  EXPECT_EQ(getRounded<uint64_t>(UINT64_MAX, 0, true),
+            SP64(UINT64_C(1) << 63, 1));
+}
+}