[PATCH v17 17/26] c++: Implement __add_rvalue_reference built-in trait

[Ken Matsui]

This patch implements built-in trait for std::add_rvalue_reference.

gcc/cp/ChangeLog:

        * cp-trait.def: Define __add_rvalue_reference.
        * semantics.cc (finish_trait_type): Handle
        CPTK_ADD_RVALUE_REFERENCE.

gcc/testsuite/ChangeLog:

        * g++.dg/ext/has-builtin-1.C: Test existence of
        __add_rvalue_reference.
        * g++.dg/ext/add_rvalue_reference.C: New test.

Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
---
 gcc/cp/cp-trait.def                           |  1 +
 gcc/cp/semantics.cc                           |  6 ++++++
 .../g++.dg/ext/add_rvalue_reference.C         | 20 +++++++++++++++++++
 gcc/testsuite/g++.dg/ext/has-builtin-1.C      |  3 +++
 4 files changed, 30 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/ext/add_rvalue_reference.C

diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index 665aea6e03f..8158c368abc 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -50,6 +50,7 @@
 
 DEFTRAIT_TYPE (ADD_LVALUE_REFERENCE, "__add_lvalue_reference", 1)
 DEFTRAIT_TYPE (ADD_POINTER, "__add_pointer", 1)
+DEFTRAIT_TYPE (ADD_RVALUE_REFERENCE, "__add_rvalue_reference", 1)
 DEFTRAIT_EXPR (HAS_NOTHROW_ASSIGN, "__has_nothrow_assign", 1)
 DEFTRAIT_EXPR (HAS_NOTHROW_CONSTRUCTOR, "__has_nothrow_constructor", 1)
 DEFTRAIT_EXPR (HAS_NOTHROW_COPY, "__has_nothrow_copy", 1)
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 9f2220a1a91..fd6d9fc1dc5 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12936,6 +12936,12 @@ finish_trait_type (cp_trait_kind kind, tree type1, 
tree type2,
        }
       return type1;
 
+    case CPTK_ADD_RVALUE_REFERENCE:
+      /* [meta.trans.ref].  */
+      if (referenceable_type_p (type1))
+       return cp_build_reference_type (type1, /*rval=*/true);
+      return type1;
+
     case CPTK_REMOVE_ALL_EXTENTS:
       return strip_array_types (type1);
 
diff --git a/gcc/testsuite/g++.dg/ext/add_rvalue_reference.C 
b/gcc/testsuite/g++.dg/ext/add_rvalue_reference.C
new file mode 100644
index 00000000000..c92fe6bfa17
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/add_rvalue_reference.C
@@ -0,0 +1,20 @@
+// { dg-do compile { target c++11 } }
+
+#define SA(X) static_assert((X),#X)
+
+class ClassType { };
+
+SA(__is_same(__add_rvalue_reference(int), int&&));
+SA(__is_same(__add_rvalue_reference(int&&), int&&));
+SA(__is_same(__add_rvalue_reference(int&), int&));
+SA(__is_same(__add_rvalue_reference(const int), const int&&));
+SA(__is_same(__add_rvalue_reference(int*), int*&&));
+SA(__is_same(__add_rvalue_reference(ClassType&&), ClassType&&));
+SA(__is_same(__add_rvalue_reference(ClassType), ClassType&&));
+SA(__is_same(__add_rvalue_reference(int(int)), int(&&)(int)));
+SA(__is_same(__add_rvalue_reference(void), void));
+SA(__is_same(__add_rvalue_reference(const void), const void));
+SA(__is_same(__add_rvalue_reference(bool(int) const), bool(int) const));
+SA(__is_same(__add_rvalue_reference(bool(int) &), bool(int) &));
+SA(__is_same(__add_rvalue_reference(bool(int) const &&), bool(int) const &&));
+SA(__is_same(__add_rvalue_reference(bool(int)), bool(&&)(int)));
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C 
b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index 4fcf41702f1..11b82714808 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -8,6 +8,9 @@
 #if !__has_builtin (__add_pointer)
 # error "__has_builtin (__add_pointer) failed"
 #endif
+#if !__has_builtin (__add_rvalue_reference)
+# error "__has_builtin (__add_rvalue_reference) failed"
+#endif
 #if !__has_builtin (__builtin_addressof)
 # error "__has_builtin (__builtin_addressof) failed"
 #endif
-- 
2.44.0