[PATCH] c++: implement __remove_pointer built-in trait

[Ken Matsui via Gcc-patches]

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

gcc/cp/ChangeLog:

* cp-trait.def: Define __remove_pointer.
* semantics.cc (finish_trait_type): Handle CPTK_REMOVE_POINTER.

gcc/testsuite/ChangeLog:

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

---
diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index bac593c0094..985b43e0d97 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -90,6 +90,7 @@ DEFTRAIT_EXPR (IS_DEDUCIBLE, "__is_deducible ", 2)
 DEFTRAIT_TYPE (REMOVE_CV, "__remove_cv", 1)
 DEFTRAIT_TYPE (REMOVE_REFERENCE, "__remove_reference", 1)
 DEFTRAIT_TYPE (REMOVE_CVREF, "__remove_cvref", 1)
+DEFTRAIT_TYPE (REMOVE_POINTER, "__remove_pointer", 1)
 DEFTRAIT_TYPE (UNDERLYING_TYPE,  "__underlying_type", 1)

 /* These traits yield a type pack, not a type, and are represented by
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 87c2e8a7111..92db1f670ac 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12273,6 +12273,10 @@ finish_trait_type (cp_trait_kind kind, tree
type1, tree type2)
       if (TYPE_REF_P (type1))
  type1 = TREE_TYPE (type1);
       return cv_unqualified (type1);
+    case CPTK_REMOVE_POINTER:
+      if (TYPE_PTR_P (type1))
+    type1 = TREE_TYPE (type1);
+      return type1;

 #define DEFTRAIT_EXPR(CODE, NAME, ARITY) \
     case CPTK_##CODE:
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index f343e153e56..e21e0a95509 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -146,3 +146,6 @@
 #if !__has_builtin (__remove_cvref)
 # error "__has_builtin (__remove_cvref) failed"
 #endif
+#if !__has_builtin (__remove_pointer)
+# error "__has_builtin (__remove_pointer) failed"
+#endif
diff --git a/gcc/testsuite/g++.dg/ext/remove_pointer.C
b/gcc/testsuite/g++.dg/ext/remove_pointer.C
new file mode 100644
index 00000000000..7b13db93950
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/remove_pointer.C
@@ -0,0 +1,51 @@
+// { dg-do compile { target c++11 } }
+
+#define SA(X) static_assert((X),#X)
+
+SA(__is_same(__remove_pointer(int), int));
+SA(__is_same(__remove_pointer(int*), int));
+SA(__is_same(__remove_pointer(int**), int*));
+
+SA(__is_same(__remove_pointer(const int*), const int));
+SA(__is_same(__remove_pointer(const int**), const int*));
+SA(__is_same(__remove_pointer(int* const), int));
+SA(__is_same(__remove_pointer(int** const), int*));
+SA(__is_same(__remove_pointer(int* const* const), int* const));
+
+SA(__is_same(__remove_pointer(volatile int*), volatile int));
+SA(__is_same(__remove_pointer(volatile int**), volatile int*));
+SA(__is_same(__remove_pointer(int* volatile), int));
+SA(__is_same(__remove_pointer(int** volatile), int*));
+SA(__is_same(__remove_pointer(int* volatile* volatile), int* volatile));
+
+SA(__is_same(__remove_pointer(const volatile int*), const volatile int));
+SA(__is_same(__remove_pointer(const volatile int**), const volatile int*));
+SA(__is_same(__remove_pointer(const int* volatile), const int));
+SA(__is_same(__remove_pointer(volatile int* const), volatile int));
+SA(__is_same(__remove_pointer(int* const volatile), int));
+SA(__is_same(__remove_pointer(const int** volatile), const int*));
+SA(__is_same(__remove_pointer(volatile int** const), volatile int*));
+SA(__is_same(__remove_pointer(int** const volatile), int*));
+SA(__is_same(__remove_pointer(int* const* const volatile), int* const));
+SA(__is_same(__remove_pointer(int* volatile* const volatile), int* volatile));
+SA(__is_same(__remove_pointer(int* const volatile* const volatile),
int* const volatile));
+
+SA(__is_same(__remove_pointer(int&), int&));
+SA(__is_same(__remove_pointer(const int&), const int&));
+SA(__is_same(__remove_pointer(volatile int&), volatile int&));
+SA(__is_same(__remove_pointer(const volatile int&), const volatile int&));
+
+SA(__is_same(__remove_pointer(int&&), int&&));
+SA(__is_same(__remove_pointer(const int&&), const int&&));
+SA(__is_same(__remove_pointer(volatile int&&), volatile int&&));
+SA(__is_same(__remove_pointer(const volatile int&&), const volatile int&&));
+
+SA(__is_same(__remove_pointer(int[3]), int[3]));
+SA(__is_same(__remove_pointer(const int[3]), const int[3]));
+SA(__is_same(__remove_pointer(volatile int[3]), volatile int[3]));
+SA(__is_same(__remove_pointer(const volatile int[3]), const volatile int[3]));
+
+SA(__is_same(__remove_pointer(int(int)), int(int)));
+SA(__is_same(__remove_pointer(int(*const)(int)), int(int)));
+SA(__is_same(__remove_pointer(int(*volatile)(int)), int(int)));
+SA(__is_same(__remove_pointer(int(*const volatile)(int)), int(int)));