[PATCH v2 3/4] c++: Implement __remove_extent built-in trait

[Ken Matsui]

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

gcc/cp/ChangeLog:

        * cp-trait.def: Define __remove_extent.
        * semantics.cc (finish_trait_type): Handle CPTK_REMOVE_EXTENT.

gcc/testsuite/ChangeLog:

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

Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
---
 gcc/cp/cp-trait.def                      |  1 +
 gcc/cp/semantics.cc                      |  5 +++++
 gcc/testsuite/g++.dg/ext/has-builtin-1.C |  3 +++
 gcc/testsuite/g++.dg/ext/remove_extent.C | 16 ++++++++++++++++
 4 files changed, 25 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/ext/remove_extent.C

diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index cec385ee501..3ff5611b60e 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -96,6 +96,7 @@ DEFTRAIT_EXPR (REF_CONSTRUCTS_FROM_TEMPORARY, 
"__reference_constructs_from_tempo
 DEFTRAIT_EXPR (REF_CONVERTS_FROM_TEMPORARY, 
"__reference_converts_from_temporary", 2)
 DEFTRAIT_TYPE (REMOVE_CV, "__remove_cv", 1)
 DEFTRAIT_TYPE (REMOVE_CVREF, "__remove_cvref", 1)
+DEFTRAIT_TYPE (REMOVE_EXTENT, "__remove_extent", 1)
 DEFTRAIT_TYPE (REMOVE_POINTER, "__remove_pointer", 1)
 DEFTRAIT_TYPE (REMOVE_REFERENCE, "__remove_reference", 1)
 DEFTRAIT_TYPE (TYPE_PACK_ELEMENT, "__type_pack_element", -1)
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index e23693ab57f..bf998377c88 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12777,6 +12777,11 @@ finish_trait_type (cp_trait_kind kind, tree type1, 
tree type2,
        type1 = TREE_TYPE (type1);
       return cv_unqualified (type1);
 
+    case CPTK_REMOVE_EXTENT:
+      if (TREE_CODE (type1) == ARRAY_TYPE)
+       type1 = TREE_TYPE (type1);
+      return type1;
+
     case CPTK_REMOVE_POINTER:
       if (TYPE_PTR_P (type1))
        type1 = TREE_TYPE (type1);
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C 
b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index 56e8db7ac32..4f1094befb9 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -170,6 +170,9 @@
 #if !__has_builtin (__remove_cvref)
 # error "__has_builtin (__remove_cvref) failed"
 #endif
+#if !__has_builtin (__remove_extent)
+# error "__has_builtin (__remove_extent) failed"
+#endif
 #if !__has_builtin (__remove_pointer)
 # error "__has_builtin (__remove_pointer) failed"
 #endif
diff --git a/gcc/testsuite/g++.dg/ext/remove_extent.C 
b/gcc/testsuite/g++.dg/ext/remove_extent.C
new file mode 100644
index 00000000000..6183aca5a48
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/remove_extent.C
@@ -0,0 +1,16 @@
+// { dg-do compile { target c++11 } }
+
+#define SA(X) static_assert((X),#X)
+
+class ClassType { };
+
+SA(__is_same(__remove_extent(int), int));
+SA(__is_same(__remove_extent(int[2]), int));
+SA(__is_same(__remove_extent(int[2][3]), int[3]));
+SA(__is_same(__remove_extent(int[][3]), int[3]));
+SA(__is_same(__remove_extent(const int[2]), const int));
+SA(__is_same(__remove_extent(ClassType), ClassType));
+SA(__is_same(__remove_extent(ClassType[2]), ClassType));
+SA(__is_same(__remove_extent(ClassType[2][3]), ClassType[3]));
+SA(__is_same(__remove_extent(ClassType[][3]), ClassType[3]));
+SA(__is_same(__remove_extent(const ClassType[2]), const ClassType));
-- 
2.43.0