This patch implements built-in trait for std::is_reference.
gcc/cp/ChangeLog:
* cp-trait.def: Define __is_reference.
* constraint.cc (diagnose_trait_expr): Handle CPTK_IS_REFERENCE.
* semantics.cc (trait_expr_value): Likewise.
(finish_trait_expr): Likewise.
gcc/testsuite/ChangeLog:
* g++.dg/ext/has-builtin-1.C: Test existence of __is_reference.
* g++.dg/ext/is_reference.C: New test.
Signed-off-by: Ken Matsui <kmat...@cs.washington.edu>
---
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_reference.C | 34 ++++++++++++++++++++++++
5 files changed, 45 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/ext/is_reference.C
diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index 8cf0f2d0974..f6951ee2670 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -3705,6 +3705,9 @@ diagnose_trait_expr (tree expr, tree args)
case CPTK_HAS_VIRTUAL_DESTRUCTOR:
inform (loc, " %qT does not have a virtual destructor", t1);
break;
+ case CPTK_IS_REFERENCE:
+ inform (loc, " %qT is not a reference", t1);
+ break;
case CPTK_IS_ABSTRACT:
inform (loc, " %qT is not an abstract class", t1);
break;
diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index 8b7fece0cc8..1e3310cd682 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -67,6 +67,7 @@ DEFTRAIT_EXPR (IS_CONVERTIBLE, "__is_convertible", 2)
DEFTRAIT_EXPR (IS_EMPTY, "__is_empty", 1)
DEFTRAIT_EXPR (IS_ENUM, "__is_enum", 1)
DEFTRAIT_EXPR (IS_FINAL, "__is_final", 1)
+DEFTRAIT_EXPR (IS_REFERENCE, "__is_reference", 1)
DEFTRAIT_EXPR (IS_LAYOUT_COMPATIBLE, "__is_layout_compatible", 2)
DEFTRAIT_EXPR (IS_LITERAL_TYPE, "__is_literal_type", 1)
DEFTRAIT_EXPR (IS_NOTHROW_ASSIGNABLE, "__is_nothrow_assignable", 2)
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index a2e74a5d2c7..2f37bc353a1 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12075,6 +12075,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree
type2)
case CPTK_IS_FINAL:
return CLASS_TYPE_P (type1) && CLASSTYPE_FINAL (type1);
+ case CPTK_IS_REFERENCE:
+ return type_code1 == REFERENCE_TYPE;
+
case CPTK_IS_LAYOUT_COMPATIBLE:
return layout_compatible_type_p (type1, type2);
@@ -12289,6 +12292,7 @@ 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_REFERENCE:
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..b697673790c 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_reference)
+# error "__has_builtin (__is_reference) failed"
+#endif
diff --git a/gcc/testsuite/g++.dg/ext/is_reference.C
b/gcc/testsuite/g++.dg/ext/is_reference.C
new file mode 100644
index 00000000000..b5ce4db7afd
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_reference.C
@@ -0,0 +1,34 @@
+// { dg-do compile { target c++11 } }
+
+#include <testsuite_tr1.h>
+
+using namespace __gnu_test;
+
+#define SA(X) static_assert((X),#X)
+#define SA_TEST_CATEGORY(TRAIT, TYPE, EXPECT) \
+ SA(TRAIT(TYPE) == EXPECT); \
+ SA(TRAIT(const TYPE) == EXPECT); \
+ SA(TRAIT(volatile TYPE) == EXPECT); \
+ SA(TRAIT(const volatile TYPE) == EXPECT)
+
+// Positive tests.
+SA_TEST_CATEGORY(__is_reference, int&, true);
+SA_TEST_CATEGORY(__is_reference, ClassType&, true);
+SA(__is_reference(int(&)(int)));
+SA_TEST_CATEGORY(__is_reference, int&&, true);
+SA_TEST_CATEGORY(__is_reference, ClassType&&, true);
+SA(__is_reference(int(&&)(int)));
+SA_TEST_CATEGORY(__is_reference, IncompleteClass&, true);
+
+// Negative tests
+SA_TEST_CATEGORY(__is_reference, void, false);
+SA_TEST_CATEGORY(__is_reference, int*, false);
+SA_TEST_CATEGORY(__is_reference, int[3], false);
+SA(!__is_reference(int(int)));
+SA(!__is_reference(int(*const)(int)));
+SA(!__is_reference(int(*volatile)(int)));
+SA(!__is_reference(int(*const volatile)(int)));
+
+// Sanity check.
+SA_TEST_CATEGORY(__is_reference, ClassType, false);
+SA_TEST_CATEGORY(__is_reference, IncompleteClass, false);
--
2.41.0
