This patch implements built-in trait for std::is_const.
gcc/cp/ChangeLog:
* cp-trait.def: Define __is_const.
* constraint.cc (diagnose_trait_expr): Handle CPTK_IS_CONST.
* semantics.cc (trait_expr_value): Likewise.
(finish_trait_expr): Likewise.
gcc/testsuite/ChangeLog:
* g++.dg/ext/has-builtin-1.C: Test existence of __is_const.
* g++.dg/ext/is_const.C: New test.
Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
---
gcc/cp/constraint.cc | 3 +++
gcc/cp/cp-trait.def | 1 +
gcc/cp/semantics.cc | 4 ++++
gcc/testsuite/g++.dg/ext/has-builtin-1.C | 3 +++
gcc/testsuite/g++.dg/ext/is_const.C | 20 ++++++++++++++++++++
5 files changed, 31 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/ext/is_const.C
diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index 49de3211d4c..f32a1c78d63 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -3767,6 +3767,9 @@ diagnose_trait_expr (tree expr, tree args)
case CPTK_IS_CLASS:
inform (loc, " %qT is not a class", t1);
break;
+ case CPTK_IS_CONST:
+ inform (loc, " %qT is not a const type", t1);
+ break;
case CPTK_IS_CONSTRUCTIBLE:
if (!t2)
inform (loc, " %qT is not default constructible", t1);
diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index 394f006f20f..36faed9c0b3 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -64,6 +64,7 @@ DEFTRAIT_EXPR (IS_ASSIGNABLE, "__is_assignable", 2)
DEFTRAIT_EXPR (IS_BASE_OF, "__is_base_of", 2)
DEFTRAIT_EXPR (IS_BOUNDED_ARRAY, "__is_bounded_array", 1)
DEFTRAIT_EXPR (IS_CLASS, "__is_class", 1)
+DEFTRAIT_EXPR (IS_CONST, "__is_const", 1)
DEFTRAIT_EXPR (IS_CONSTRUCTIBLE, "__is_constructible", -1)
DEFTRAIT_EXPR (IS_CONVERTIBLE, "__is_convertible", 2)
DEFTRAIT_EXPR (IS_EMPTY, "__is_empty", 1)
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 57840176863..0d08900492b 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12446,6 +12446,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree
type2)
case CPTK_IS_CLASS:
return NON_UNION_CLASS_TYPE_P (type1);
+ case CPTK_IS_CONST:
+ return CP_TYPE_CONST_P (type1);
+
case CPTK_IS_CONSTRUCTIBLE:
return is_xible (INIT_EXPR, type1, type2);
@@ -12688,6 +12691,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind,
tree type1, tree type2)
case CPTK_IS_ARRAY:
case CPTK_IS_BOUNDED_ARRAY:
case CPTK_IS_CLASS:
+ case CPTK_IS_CONST:
case CPTK_IS_ENUM:
case CPTK_IS_FUNCTION:
case CPTK_IS_MEMBER_FUNCTION_POINTER:
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index 02b4b4d745d..e3640faeb96 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -71,6 +71,9 @@
#if !__has_builtin (__is_class)
# error "__has_builtin (__is_class) failed"
#endif
+#if !__has_builtin (__is_const)
+# error "__has_builtin (__is_const) failed"
+#endif
#if !__has_builtin (__is_constructible)
# error "__has_builtin (__is_constructible) failed"
#endif
diff --git a/gcc/testsuite/g++.dg/ext/is_const.C
b/gcc/testsuite/g++.dg/ext/is_const.C
new file mode 100644
index 00000000000..8a0e8df72a9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_const.C
@@ -0,0 +1,20 @@
+// { dg-do compile { target c++11 } }
+
+#define SA(X) static_assert((X),#X)
+
+class ClassType { };
+using cClassType = const ClassType;
+using vClassType = volatile ClassType;
+using cvClassType = const volatile ClassType;
+
+// Positive tests.
+SA(__is_const(const int));
+SA(__is_const(const volatile int));
+SA(__is_const(cClassType));
+SA(__is_const(cvClassType));
+
+// Negative tests.
+SA(!__is_const(int));
+SA(!__is_const(volatile int));
+SA(!__is_const(ClassType));
+SA(!__is_const(vClassType));
--
2.43.2
