[PATCH] D86354: [ADT] Make Optional a literal type.

[Varun Gandhi via Phabricator via llvm-commits]

varungandhi-apple created this revision.
varungandhi-apple added a reviewer: fhahn.
Herald added subscribers: llvm-commits, dexonsmith.
Herald added a project: LLVM.
varungandhi-apple requested review of this revision.

This allows returning Optional values from constexpr contexts.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D86354

Files:
  llvm/include/llvm/ADT/Optional.h
  llvm/unittests/ADT/OptionalTest.cpp


Index: llvm/unittests/ADT/OptionalTest.cpp
===================================================================
--- llvm/unittests/ADT/OptionalTest.cpp
+++ llvm/unittests/ADT/OptionalTest.cpp
@@ -17,6 +17,13 @@
 
 using namespace llvm;
 
+static_assert(
+    std::is_literal_type<optional_detail::OptionalStorage<int>>::value,
+    "Optional should be usable in constexpr");
+
+static_assert(std::is_literal_type<Optional<int>>::value,
+              "Optional should be usable in constexpr");
+
 static_assert(is_trivially_copyable<Optional<int>>::value,
           "trivially copyable");
 
Index: llvm/include/llvm/ADT/Optional.h
===================================================================
--- llvm/include/llvm/ADT/Optional.h
+++ llvm/include/llvm/ADT/Optional.h
@@ -43,7 +43,7 @@
 public:
   ~OptionalStorage() { reset(); }
 
-  OptionalStorage() noexcept : empty(), hasVal(false) {}
+  constexpr OptionalStorage() noexcept : empty(), hasVal(false) {}
 
   OptionalStorage(OptionalStorage const &other) : OptionalStorage() {
     if (other.hasValue()) {
@@ -148,7 +148,7 @@
 public:
   ~OptionalStorage() = default;
 
-  OptionalStorage() noexcept : empty{} {}
+  constexpr OptionalStorage() noexcept : empty{} {}
 
   OptionalStorage(OptionalStorage const &other) = default;
   OptionalStorage(OptionalStorage &&other) = default;


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