[llvm] r245518 - Allow Optionals to be compared to None

[David Blaikie via llvm-commits]

Author: dblaikie
Date: Wed Aug 19 18:07:27 2015
New Revision: 245518

URL: http://llvm.org/viewvc/llvm-project?rev=245518&view=rev
Log:
Allow Optionals to be compared to None

This is something like nullopt in std::experimental::optional. Optional
could already be constructed from None, so this seems like an obvious
extension from there.

I have a use in a future patch for Clang, though it may not go that
way/end up used - so this seemed worth committing now regardless.

Modified:
    llvm/trunk/include/llvm/ADT/Optional.h
    llvm/trunk/unittests/ADT/OptionalTest.cpp

Modified: llvm/trunk/include/llvm/ADT/Optional.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/Optional.h?rev=245518&r1=245517&r2=245518&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/Optional.h (original)
+++ llvm/trunk/include/llvm/ADT/Optional.h Wed Aug 19 18:07:27 2015
@@ -159,6 +159,25 @@ template <typename T> struct isPodLike<O
 template<typename T, typename U>
 void operator==(const Optional<T> &X, const Optional<U> &Y);
 
+template<typename T>
+bool operator==(const Optional<T> &X, NoneType) {
+  return !X.hasValue();
+}
+
+template<typename T>
+bool operator==(NoneType, const Optional<T> &X) {
+  return X == None;
+}
+
+template<typename T>
+bool operator!=(const Optional<T> &X, NoneType) {
+  return !(X == None);
+}
+
+template<typename T>
+bool operator!=(NoneType, const Optional<T> &X) {
+  return X != None;
+}
 /// \brief Poison comparison between two \c Optional objects. Clients needs to
 /// explicitly compare the underlying values and account for empty \c Optional
 /// objects.

Modified: llvm/trunk/unittests/ADT/OptionalTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/OptionalTest.cpp?rev=245518&r1=245517&r2=245518&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/OptionalTest.cpp (original)
+++ llvm/trunk/unittests/ADT/OptionalTest.cpp Wed Aug 19 18:07:27 2015
@@ -377,5 +377,18 @@ TEST_F(OptionalTest, MoveGetValueOr) {
 
 #endif // LLVM_HAS_RVALUE_REFERENCE_THIS
 
+TEST_F(OptionalTest, NoneComparison) {
+  Optional<int> o;
+  EXPECT_EQ(o, None);
+  EXPECT_EQ(None, o);
+  EXPECT_FALSE(o != None);
+  EXPECT_FALSE(None != o);
+  o = 3;
+  EXPECT_FALSE(o == None);
+  EXPECT_FALSE(None == o);
+  EXPECT_TRUE(o != None);
+  EXPECT_TRUE(None != o);
+}
+
 } // end anonymous namespace