[gcc r14-6378] c++: Implement __is_object built-in trait

[Jason Merrill]

https://gcc.gnu.org/g:692080219c2ecf2cde9360a3b179f491e867afb8

commit r14-6378-g692080219c2ecf2cde9360a3b179f491e867afb8
Author: Ken Matsui <kmatsui@gcc.gnu.org>
Date:   Wed Dec 6 21:33:15 2023 -0800

    c++: Implement __is_object built-in trait
    
    This patch implements built-in trait for std::is_object.
    
    gcc/cp/ChangeLog:
    
            * cp-trait.def: Define __is_object.
            * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_OBJECT.
            * semantics.cc (trait_expr_value): Likewise.
            (finish_trait_expr): Likewise.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/ext/has-builtin-1.C: Test existence of __is_object.
            * g++.dg/ext/is_object.C: New test.
    
    Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>

Diff:
---
 gcc/cp/constraint.cc                     |  3 +++
 gcc/cp/semantics.cc                      |  6 ++++++
 gcc/testsuite/g++.dg/ext/has-builtin-1.C |  3 +++
 gcc/testsuite/g++.dg/ext/is_object.C     | 29 +++++++++++++++++++++++++++++
 gcc/cp/cp-trait.def                      |  1 +
 5 files changed, 42 insertions(+)

diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index 4bea6089791..eeacead52a5 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -3782,6 +3782,9 @@ diagnose_trait_expr (tree expr, tree args)
     case CPTK_IS_NOTHROW_CONVERTIBLE:
 	  inform (loc, "  %qT is not nothrow convertible from %qE", t2, t1);
       break;
+    case CPTK_IS_OBJECT:
+      inform (loc, "  %qT is not an object type", t1);
+      break;
     case CPTK_IS_POINTER_INTERCONVERTIBLE_BASE_OF:
       inform (loc, "  %qT is not pointer-interconvertible base of %qT",
 	      t1, t2);
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 4a95af477e7..6420159e0b0 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12446,6 +12446,11 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_NOTHROW_CONVERTIBLE:
       return is_nothrow_convertible (type1, type2);
 
+    case CPTK_IS_OBJECT:
+      return (type_code1 != FUNCTION_TYPE
+	      && type_code1 != REFERENCE_TYPE
+	      && type_code1 != VOID_TYPE);
+
     case CPTK_IS_POINTER_INTERCONVERTIBLE_BASE_OF:
       return pointer_interconvertible_base_of_p (type1, type2);
 
@@ -12646,6 +12651,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_MEMBER_FUNCTION_POINTER:
     case CPTK_IS_MEMBER_OBJECT_POINTER:
     case CPTK_IS_MEMBER_POINTER:
+    case CPTK_IS_OBJECT:
     case CPTK_IS_REFERENCE:
     case CPTK_IS_SAME:
     case CPTK_IS_SCOPED_ENUM:
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index 5215da27d6f..2242276f633 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -113,6 +113,9 @@
 #if !__has_builtin (__is_nothrow_convertible)
 # error "__has_builtin (__is_nothrow_convertible) failed"
 #endif
+#if !__has_builtin (__is_object)
+# error "__has_builtin (__is_object) failed"
+#endif
 #if !__has_builtin (__is_pointer_interconvertible_base_of)
 # error "__has_builtin (__is_pointer_interconvertible_base_of) failed"
 #endif
diff --git a/gcc/testsuite/g++.dg/ext/is_object.C b/gcc/testsuite/g++.dg/ext/is_object.C
new file mode 100644
index 00000000000..5c759a5ef69
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_object.C
@@ -0,0 +1,29 @@
+// { dg-do compile { target c++11 } }
+
+#include <testsuite_tr1.h>
+
+using namespace __gnu_test;
+
+#define SA(X) static_assert((X),#X)
+
+#define SA_TEST_NON_VOLATILE(TRAIT, TYPE, EXPECT)	\
+  SA(TRAIT(TYPE) == EXPECT);				\
+  SA(TRAIT(const TYPE) == EXPECT)
+
+#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)
+
+SA_TEST_NON_VOLATILE(__is_object, int (int), false);
+SA_TEST_NON_VOLATILE(__is_object, ClassType (ClassType), false);
+SA_TEST_NON_VOLATILE(__is_object,
+		     float (int, float, int[], int&), false);
+SA_TEST_CATEGORY(__is_object, int&, false);
+SA_TEST_CATEGORY(__is_object, ClassType&, false);
+SA_TEST_NON_VOLATILE(__is_object, int(&)(int), false);
+SA_TEST_CATEGORY(__is_object, void, false);
+
+// Sanity check.
+SA_TEST_CATEGORY(__is_object, ClassType, true);
diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index 89712f18667..b833efff26e 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -78,6 +78,7 @@ DEFTRAIT_EXPR (IS_MEMBER_POINTER, "__is_member_pointer", 1)
 DEFTRAIT_EXPR (IS_NOTHROW_ASSIGNABLE, "__is_nothrow_assignable", 2)
 DEFTRAIT_EXPR (IS_NOTHROW_CONSTRUCTIBLE, "__is_nothrow_constructible", -1)
 DEFTRAIT_EXPR (IS_NOTHROW_CONVERTIBLE, "__is_nothrow_convertible", 2)
+DEFTRAIT_EXPR (IS_OBJECT, "__is_object", 1)
 DEFTRAIT_EXPR (IS_POINTER_INTERCONVERTIBLE_BASE_OF, "__is_pointer_interconvertible_base_of", 2)
 DEFTRAIT_EXPR (IS_POD, "__is_pod", 1)
 DEFTRAIT_EXPR (IS_POLYMORPHIC, "__is_polymorphic", 1)