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 | 19 +++++++++++++++++++
5 files changed, 30 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 8cf0f2d0974..ff4ae831def 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -3751,6 +3751,9 @@ diagnose_trait_expr (tree expr, tree args)
case CPTK_IS_UNION:
inform (loc, " %qT is not a union", t1);
break;
+ case CPTK_IS_CONST:
+ inform (loc, " %qT is not a const type", t1);
+ break;
case CPTK_IS_AGGREGATE:
inform (loc, " %qT is not an aggregate", t1);
break;
diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index 8b7fece0cc8..b40b475b86d 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -82,6 +82,7 @@ DEFTRAIT_EXPR (IS_TRIVIALLY_ASSIGNABLE,
"__is_trivially_assignable", 2)
DEFTRAIT_EXPR (IS_TRIVIALLY_CONSTRUCTIBLE, "__is_trivially_constructible", -1)
DEFTRAIT_EXPR (IS_TRIVIALLY_COPYABLE, "__is_trivially_copyable", 1)
DEFTRAIT_EXPR (IS_UNION, "__is_union", 1)
+DEFTRAIT_EXPR (IS_CONST, "__is_const", 1)
DEFTRAIT_EXPR (REF_CONSTRUCTS_FROM_TEMPORARY,
"__reference_constructs_from_temporary", 2)
DEFTRAIT_EXPR (REF_CONVERTS_FROM_TEMPORARY,
"__reference_converts_from_temporary", 2)
/* FIXME Added space to avoid direct usage in GCC 13. */
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 8fb47fd179e..011ba8e46e1 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12079,6 +12079,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree
type2)
case CPTK_IS_ENUM:
return type_code1 == ENUMERAL_TYPE;
+ case CPTK_IS_CONST:
+ return CP_TYPE_CONST_P (type1);
+
case CPTK_IS_FINAL:
return CLASS_TYPE_P (type1) && CLASSTYPE_FINAL (type1);
@@ -12296,6 +12299,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind,
tree type1, tree type2)
case CPTK_IS_ENUM:
case CPTK_IS_UNION:
case CPTK_IS_SAME:
+ case CPTK_IS_CONST:
break;
case CPTK_IS_LAYOUT_COMPATIBLE:
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index f343e153e56..965309a333a 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 (__is_const)
+# error "__has_builtin (__is_const) 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..8f2d7c2fce9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_const.C
@@ -0,0 +1,19 @@
+// { dg-do compile { target c++11 } }
+
+#include <testsuite_tr1.h>
+
+using namespace __gnu_test;
+
+#define SA(X) static_assert((X),#X)
+
+// 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));
--
2.41.0
