Re: [PATCH v14 19/26] c++: Implement __decay built-in trait

2024-04-30 Thread Jason Merrill 

On 2/28/24 11:26, Ken Matsui wrote:

This patch implements built-in trait for std::decay.


OK.


gcc/cp/ChangeLog:

* cp-trait.def: Define __decay.
* semantics.cc (finish_trait_type): Handle CPTK_DECAY.

gcc/testsuite/ChangeLog:

* g++.dg/ext/has-builtin-1.C: Test existence of __decay.
* g++.dg/ext/decay.C: New test.

Signed-off-by: Ken Matsui 
---
  gcc/cp/cp-trait.def  |  1 +
  gcc/cp/semantics.cc  | 12 
  gcc/testsuite/g++.dg/ext/decay.C | 22 ++
  gcc/testsuite/g++.dg/ext/has-builtin-1.C |  3 +++
  4 files changed, 38 insertions(+)
  create mode 100644 gcc/testsuite/g++.dg/ext/decay.C

diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index 173818adf79..2d1cb7c227c 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -51,6 +51,7 @@
  DEFTRAIT_TYPE (ADD_LVALUE_REFERENCE, "__add_lvalue_reference", 1)
  DEFTRAIT_TYPE (ADD_POINTER, "__add_pointer", 1)
  DEFTRAIT_TYPE (ADD_RVALUE_REFERENCE, "__add_rvalue_reference", 1)
+DEFTRAIT_TYPE (DECAY, "__decay", 1)
  DEFTRAIT_EXPR (HAS_NOTHROW_ASSIGN, "__has_nothrow_assign", 1)
  DEFTRAIT_EXPR (HAS_NOTHROW_CONSTRUCTOR, "__has_nothrow_constructor", 1)
  DEFTRAIT_EXPR (HAS_NOTHROW_COPY, "__has_nothrow_copy", 1)
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 19d6f87a9ea..45dc509855a 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12801,6 +12801,18 @@ finish_trait_type (cp_trait_kind kind, tree type1, 
tree type2,
return type1;
return cp_build_reference_type (type1, /*rval=*/true);
  
+case CPTK_DECAY:

+  if (TYPE_REF_P (type1))
+   type1 = TREE_TYPE (type1);
+
+  if (TREE_CODE (type1) == ARRAY_TYPE)
+   return finish_trait_type (CPTK_ADD_POINTER, TREE_TYPE (type1), type2,
+ complain);
+  else if (TREE_CODE (type1) == FUNCTION_TYPE)
+   return finish_trait_type (CPTK_ADD_POINTER, type1, type2, complain);
+  else
+   return cv_unqualified (type1);
+
  case CPTK_REMOVE_ALL_EXTENTS:
return strip_array_types (type1);
  
diff --git a/gcc/testsuite/g++.dg/ext/decay.C b/gcc/testsuite/g++.dg/ext/decay.C

new file mode 100644
index 000..8adedfeefe6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/decay.C
@@ -0,0 +1,22 @@
+// { dg-do compile { target c++11 } }
+
+#define SA(X) static_assert((X),#X)
+
+// Positive tests.
+using test1_type = __decay(bool);
+SA(__is_same(test1_type, bool));
+
+// NB: DR 705.
+using test2_type = __decay(const int);
+SA(__is_same(test2_type, int));
+
+using test3_type = __decay(int[4]);
+SA(__is_same(test3_type, __remove_extent(int[4])*));
+
+using fn_type = void ();
+using test4_type = __decay(fn_type);
+SA(__is_same(test4_type, __add_pointer(fn_type)));
+
+using cfn_type = void () const;
+using test5_type = __decay(cfn_type);
+SA(__is_same(test5_type, cfn_type));
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C 
b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index c2503c5d82b..3aca273aad6 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -11,6 +11,9 @@
  #if !__has_builtin (__add_rvalue_reference)
  # error "__has_builtin (__add_rvalue_reference) failed"
  #endif
+#if !__has_builtin (__decay)
+# error "__has_builtin (__decay) failed"
+#endif
  #if !__has_builtin (__builtin_addressof)
  # error "__has_builtin (__builtin_addressof) failed"
  #endif

[PATCH v14 19/26] c++: Implement __decay built-in trait

2024-02-28 Thread Ken Matsui 
This patch implements built-in trait for std::decay.

gcc/cp/ChangeLog:

* cp-trait.def: Define __decay.
* semantics.cc (finish_trait_type): Handle CPTK_DECAY.

gcc/testsuite/ChangeLog:

* g++.dg/ext/has-builtin-1.C: Test existence of __decay.
* g++.dg/ext/decay.C: New test.

Signed-off-by: Ken Matsui 
---
 gcc/cp/cp-trait.def  |  1 +
 gcc/cp/semantics.cc  | 12 
 gcc/testsuite/g++.dg/ext/decay.C | 22 ++
 gcc/testsuite/g++.dg/ext/has-builtin-1.C |  3 +++
 4 files changed, 38 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/ext/decay.C

diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index 173818adf79..2d1cb7c227c 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -51,6 +51,7 @@
 DEFTRAIT_TYPE (ADD_LVALUE_REFERENCE, "__add_lvalue_reference", 1)
 DEFTRAIT_TYPE (ADD_POINTER, "__add_pointer", 1)
 DEFTRAIT_TYPE (ADD_RVALUE_REFERENCE, "__add_rvalue_reference", 1)
+DEFTRAIT_TYPE (DECAY, "__decay", 1)
 DEFTRAIT_EXPR (HAS_NOTHROW_ASSIGN, "__has_nothrow_assign", 1)
 DEFTRAIT_EXPR (HAS_NOTHROW_CONSTRUCTOR, "__has_nothrow_constructor", 1)
 DEFTRAIT_EXPR (HAS_NOTHROW_COPY, "__has_nothrow_copy", 1)
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 19d6f87a9ea..45dc509855a 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12801,6 +12801,18 @@ finish_trait_type (cp_trait_kind kind, tree type1, 
tree type2,
return type1;
   return cp_build_reference_type (type1, /*rval=*/true);
 
+case CPTK_DECAY:
+  if (TYPE_REF_P (type1))
+   type1 = TREE_TYPE (type1);
+
+  if (TREE_CODE (type1) == ARRAY_TYPE)
+   return finish_trait_type (CPTK_ADD_POINTER, TREE_TYPE (type1), type2,
+ complain);
+  else if (TREE_CODE (type1) == FUNCTION_TYPE)
+   return finish_trait_type (CPTK_ADD_POINTER, type1, type2, complain);
+  else
+   return cv_unqualified (type1);
+
 case CPTK_REMOVE_ALL_EXTENTS:
   return strip_array_types (type1);
 
diff --git a/gcc/testsuite/g++.dg/ext/decay.C b/gcc/testsuite/g++.dg/ext/decay.C
new file mode 100644
index 000..8adedfeefe6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/decay.C
@@ -0,0 +1,22 @@
+// { dg-do compile { target c++11 } }
+
+#define SA(X) static_assert((X),#X)
+
+// Positive tests.
+using test1_type = __decay(bool);
+SA(__is_same(test1_type, bool));
+
+// NB: DR 705.
+using test2_type = __decay(const int);
+SA(__is_same(test2_type, int));
+
+using test3_type = __decay(int[4]);
+SA(__is_same(test3_type, __remove_extent(int[4])*));
+
+using fn_type = void ();
+using test4_type = __decay(fn_type);
+SA(__is_same(test4_type, __add_pointer(fn_type)));
+
+using cfn_type = void () const;
+using test5_type = __decay(cfn_type);
+SA(__is_same(test5_type, cfn_type));
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C 
b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index c2503c5d82b..3aca273aad6 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -11,6 +11,9 @@
 #if !__has_builtin (__add_rvalue_reference)
 # error "__has_builtin (__add_rvalue_reference) failed"
 #endif
+#if !__has_builtin (__decay)
+# error "__has_builtin (__decay) failed"
+#endif
 #if !__has_builtin (__builtin_addressof)
 # error "__has_builtin (__builtin_addressof) failed"
 #endif
-- 
2.44.0