[PATCH v14 09/26] c++: Implement __add_pointer built-in trait

[Ken Matsui]

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

gcc/cp/ChangeLog:

        * cp-trait.def: Define __add_pointer.
        * semantics.cc (finish_trait_type): Handle CPTK_ADD_POINTER.

gcc/testsuite/ChangeLog:

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

Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
---
 gcc/cp/cp-trait.def                      |  1 +
 gcc/cp/semantics.cc                      |  9 ++++++
 gcc/testsuite/g++.dg/ext/add_pointer.C   | 39 ++++++++++++++++++++++++
 gcc/testsuite/g++.dg/ext/has-builtin-1.C |  3 ++
 4 files changed, 52 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/ext/add_pointer.C

diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index 05514a51c21..63f879287ce 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -48,6 +48,7 @@
 #define DEFTRAIT_TYPE_DEFAULTED
 #endif
 
+DEFTRAIT_TYPE (ADD_POINTER, "__add_pointer", 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 1794e83baa2..635441a7a90 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12776,6 +12776,15 @@ finish_trait_type (cp_trait_kind kind, tree type1, 
tree type2,
 
   switch (kind)
     {
+    case CPTK_ADD_POINTER:
+      if (FUNC_OR_METHOD_TYPE_P (type1)
+         && (type_memfn_quals (type1) != TYPE_UNQUALIFIED
+             || type_memfn_rqual (type1) != REF_QUAL_NONE))
+       return type1;
+      if (TYPE_REF_P (type1))
+       type1 = TREE_TYPE (type1);
+      return build_pointer_type (type1);
+
     case CPTK_REMOVE_CV:
       return cv_unqualified (type1);
 
diff --git a/gcc/testsuite/g++.dg/ext/add_pointer.C 
b/gcc/testsuite/g++.dg/ext/add_pointer.C
new file mode 100644
index 00000000000..c405cdd0feb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/add_pointer.C
@@ -0,0 +1,39 @@
+// { dg-do compile { target c++11 } }
+
+#define SA(X) static_assert((X),#X)
+
+class ClassType { };
+
+SA(__is_same(__add_pointer(int), int*));
+SA(__is_same(__add_pointer(int*), int**));
+SA(__is_same(__add_pointer(const int), const int*));
+SA(__is_same(__add_pointer(int&), int*));
+SA(__is_same(__add_pointer(ClassType*), ClassType**));
+SA(__is_same(__add_pointer(ClassType), ClassType*));
+SA(__is_same(__add_pointer(void), void*));
+SA(__is_same(__add_pointer(const void), const void*));
+SA(__is_same(__add_pointer(volatile void), volatile void*));
+SA(__is_same(__add_pointer(const volatile void), const volatile void*));
+
+void f1();
+using f1_type = decltype(f1);
+using pf1_type = decltype(&f1);
+SA(__is_same(__add_pointer(f1_type), pf1_type));
+
+void f2() noexcept; // PR libstdc++/78361
+using f2_type = decltype(f2);
+using pf2_type = decltype(&f2);
+SA(__is_same(__add_pointer(f2_type), pf2_type));
+
+using fn_type = void();
+using pfn_type = void(*)();
+SA(__is_same(__add_pointer(fn_type), pfn_type));
+
+SA(__is_same(__add_pointer(void() &), void() &));
+SA(__is_same(__add_pointer(void() & noexcept), void() & noexcept));
+SA(__is_same(__add_pointer(void() const), void() const));
+SA(__is_same(__add_pointer(void(...) &), void(...) &));
+SA(__is_same(__add_pointer(void(...) & noexcept), void(...) & noexcept));
+SA(__is_same(__add_pointer(void(...) const), void(...) const));
+
+SA(__is_same(__add_pointer(void() __restrict), void() __restrict));
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C 
b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index b1430e9bd8b..9d861398bae 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -2,6 +2,9 @@
 // { dg-do compile }
 // Verify that __has_builtin gives the correct answer for C++ built-ins.
 
+#if !__has_builtin (__add_pointer)
+# error "__has_builtin (__add_pointer) failed"
+#endif
 #if !__has_builtin (__builtin_addressof)
 # error "__has_builtin (__builtin_addressof) failed"
 #endif
-- 
2.44.0