[1/2] c++: implement __is_reference built-in trait
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Commit Message
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.
---
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 | 26 ++++++++++++++++++++++++
5 files changed, 37 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/ext/is_reference.C
@@ -3701,6 +3701,9 @@ 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;
@@ -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)
@@ -11995,6 +11995,9 @@ 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);
@@ -12139,6 +12142,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
case CPTK_HAS_TRIVIAL_COPY:
case CPTK_HAS_TRIVIAL_DESTRUCTOR:
case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS:
+ case CPTK_IS_REFERENCE:
if (!check_trait_type (type1))
return error_mark_node;
break;
@@ -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
new file mode 100644
@@ -0,0 +1,26 @@
+// { dg-do compile { target c++11 } }
+
+#define SA(X) static_assert((X),#X)
+
+SA(!__is_reference(void));
+SA(!__is_reference(int*));
+
+SA(__is_reference(int&));
+SA(__is_reference(const int&));
+SA(__is_reference(volatile int&));
+SA(__is_reference(const volatile int&));
+
+SA(__is_reference(int&&));
+SA(__is_reference(const int&&));
+SA(__is_reference(volatile int&&));
+SA(__is_reference(const volatile int&&));
+
+SA(!__is_reference(int[3]));
+SA(!__is_reference(const int[3]));
+SA(!__is_reference(volatile int[3]));
+SA(!__is_reference(const volatile int[3]));
+
+SA(!__is_reference(int(int)));
+SA(!__is_reference(int(*const)(int)));
+SA(!__is_reference(int(*volatile)(int)));
+SA(!__is_reference(int(*const volatile)(int)));