Clang support for __is_assignable intrinsic

MSVC now supports the __is_assignable type trait intrinsic,
to enable easier and more efficient implementation of the
Standard Library's is_assignable trait.
As of Visual Studio 2015 Update 3, the VC Standard Library
implementation uses the new intrinsic unconditionally.

The implementation is pretty straightforward due to the previously
existing is_nothrow_assignable and is_trivially_assignable.
We handle __is_assignable via the same code as the other two except
that we skip the extra checks for nothrow or triviality.

Patch by Dave Bartolomeo!

Differential Revision: http://reviews.llvm.org/D20492

llvm-svn: 270458

4 files changed, 50 insertions, 0 deletions

diff --git a/clang/test/Lexer/has_feature_type_traits.cpp b/clang/test/Lexer/has_feature_type_traits.cpp
index f772d6d1845..6636e7b3963 100644
--- a/clang/test/Lexer/has_feature_type_traits.cpp
+++ b/clang/test/Lexer/has_feature_type_traits.cpp
@@ -45,6 +45,11 @@ int is_abstract();
 #endif
 // CHECK: int is_abstract();
 
+#if __has_feature(is_assignable)
+int is_assignable();
+#endif
+// CHECK: int is_assignable();
+
 #if __has_feature(is_base_of)
 int is_base_of();
 #endif
diff --git a/clang/test/PCH/cxx-traits.cpp b/clang/test/PCH/cxx-traits.cpp
index fc3e1335dd6..b0f1d9d2c3d 100644
--- a/clang/test/PCH/cxx-traits.cpp
+++ b/clang/test/PCH/cxx-traits.cpp
@@ -18,6 +18,7 @@ bool copy_construct_int = n::is_trivially_constructible<int, const int&>::value;
 bool _is_abstract_result = __is_abstract(int);
 bool _is_arithmetic_result = __is_arithmetic(int);
 bool _is_array_result = __is_array(int);
+bool _is_assignable_result = __is_assignable(int, int);
 bool _is_base_of_result = __is_base_of(int, int);
 bool _is_class_result = __is_class(int);
 bool _is_complete_type_result = __is_complete_type(int);
diff --git a/clang/test/PCH/cxx-traits.h b/clang/test/PCH/cxx-traits.h
index 21324768186..1d7d40450fe 100644
--- a/clang/test/PCH/cxx-traits.h
+++ b/clang/test/PCH/cxx-traits.h
@@ -20,6 +20,7 @@ struct is_trivially_constructible {
 struct __is_abstract {};  // expected-warning {{made available}}
 struct __is_arithmetic {};  // expected-warning {{made available}}
 struct __is_array {};  // expected-warning {{made available}}
+struct __is_assignable {};  // expected-warning {{made available}}
 struct __is_base_of {};  // expected-warning {{made available}}
 struct __is_class {};  // expected-warning {{made available}}
 struct __is_complete_type {};  // expected-warning {{made available}}
diff --git a/clang/test/SemaCXX/type-traits.cpp b/clang/test/SemaCXX/type-traits.cpp
index 69760fd6bd0..c53b02774ac 100644
--- a/clang/test/SemaCXX/type-traits.cpp
+++ b/clang/test/SemaCXX/type-traits.cpp
@@ -1514,6 +1514,9 @@ void has_nothrow_move_assign() {
 
   { int arr[T(__is_nothrow_assignable(HasNoThrowMoveAssign, HasNoThrowMoveAssign))]; }
   { int arr[F(__is_nothrow_assignable(HasThrowMoveAssign, HasThrowMoveAssign))]; }
+
+  { int arr[T(__is_assignable(HasNoThrowMoveAssign, HasNoThrowMoveAssign))]; }
+  { int arr[T(__is_assignable(HasThrowMoveAssign, HasThrowMoveAssign))]; }
 }
 
 void has_trivial_move_assign() {
@@ -1974,6 +1977,46 @@ void trivial_checks()
                                          TrivialMoveButNotCopy)))]; }
   { int arr[T((__is_trivially_assignable(TrivialMoveButNotCopy&,
                                          TrivialMoveButNotCopy&&)))]; }
+  { int arr[T((__is_trivially_assignable(int&, int)))]; }
+  { int arr[T((__is_trivially_assignable(int&, int&)))]; }
+  { int arr[T((__is_trivially_assignable(int&, int&&)))]; }
+  { int arr[T((__is_trivially_assignable(int&, const int&)))]; }
+  { int arr[T((__is_trivially_assignable(POD&, POD)))]; }
+  { int arr[T((__is_trivially_assignable(POD&, POD&)))]; }
+  { int arr[T((__is_trivially_assignable(POD&, POD&&)))]; }
+  { int arr[T((__is_trivially_assignable(POD&, const POD&)))]; }
+  { int arr[T((__is_trivially_assignable(int*&, int*)))]; }
+  { int arr[T((__is_trivially_assignable(AllDefaulted,
+                                         const AllDefaulted &)))]; }
+  { int arr[T((__is_trivially_assignable(AllDefaulted,
+                                         AllDefaulted &&)))]; }
+
+  { int arr[F((__is_assignable(int *&, float *)))]; }
+  { int arr[T((__is_assignable(HasCopyAssign &, HasCopyAssign)))]; }
+  { int arr[T((__is_assignable(HasCopyAssign &, HasCopyAssign &)))]; }
+  { int arr[T((__is_assignable(HasCopyAssign &, const HasCopyAssign &)))]; }
+  { int arr[T((__is_assignable(HasCopyAssign &, HasCopyAssign &&)))]; }
+  { int arr[T((__is_assignable(TrivialMoveButNotCopy &,
+                               TrivialMoveButNotCopy &)))]; }
+  { int arr[T((__is_assignable(TrivialMoveButNotCopy &,
+                               const TrivialMoveButNotCopy &)))]; }
+  { int arr[F((__is_assignable(AllDeleted,
+                               const AllDeleted &)))]; }
+  { int arr[F((__is_assignable(AllDeleted,
+                               AllDeleted &&)))]; }
+  { int arr[T((__is_assignable(ExtDefaulted,
+                               const ExtDefaulted &)))]; }
+  { int arr[T((__is_assignable(ExtDefaulted,
+                               ExtDefaulted &&)))]; }
+
+  { int arr[T((__is_assignable(HasDefaultTrivialCopyAssign &,
+                               HasDefaultTrivialCopyAssign &)))]; }
+  { int arr[T((__is_assignable(HasDefaultTrivialCopyAssign &,
+                               const HasDefaultTrivialCopyAssign &)))]; }
+  { int arr[T((__is_assignable(TrivialMoveButNotCopy &,
+                               TrivialMoveButNotCopy)))]; }
+  { int arr[T((__is_assignable(TrivialMoveButNotCopy &,
+                               TrivialMoveButNotCopy &&)))]; }
 }
 
 void constructible_checks() {