[PATCH, OpenMP, C++] Allow classes with static members to be mappable

[Chung-Lin Tang]

Hi Jakub,
Now in OpenMP 5.x, static members are supposed to be not a barrier for a class
to be target-mapped.

There is the related issue of actually providing access to static 
const/constexpr
members on the GPU (probably a case of 
https://github.com/OpenMP/spec/issues/2158)
but that is for later.

This patch basically just removes the check for static members inside
cp_omp_mappable_type_1, and adjusts a testcase. Not sure if more tests are 
needed.
Tested on trunk without regressions, okay when stage1 reopens?

Thanks,
Chung-Lin

2022-03-09  Chung-Lin Tang  <clt...@codesourcery.com>

gcc/cp/ChangeLog:

        * decl2.cc (cp_omp_mappable_type_1): Remove requirement that all
        members must be non-static; remove check for static fields.

gcc/testsuite/ChangeLog:

        * g++.dg/gomp/unmappable-1.C: Adjust testcase.
diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index c53acf4546d..ace7783d9bd 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -1544,21 +1544,14 @@ cp_omp_mappable_type_1 (tree type, bool notes)
   /* Arrays have mappable type if the elements have mappable type.  */
   while (TREE_CODE (type) == ARRAY_TYPE)
     type = TREE_TYPE (type);
-  /* All data members must be non-static.  */
+
   if (CLASS_TYPE_P (type))
     {
       tree field;
       for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
-       if (VAR_P (field))
-         {
-           if (notes)
-             inform (DECL_SOURCE_LOCATION (field),
-                     "static field %qD is not mappable", field);
-           result = false;
-         }
        /* All fields must have mappable types.  */
-       else if (TREE_CODE (field) == FIELD_DECL
-                && !cp_omp_mappable_type_1 (TREE_TYPE (field), notes))
+       if (TREE_CODE (field) == FIELD_DECL
+           && !cp_omp_mappable_type_1 (TREE_TYPE (field), notes))
          result = false;
     }
   return result;
diff --git a/gcc/testsuite/g++.dg/gomp/unmappable-1.C 
b/gcc/testsuite/g++.dg/gomp/unmappable-1.C
index 364f884500c..1532b9c73f1 100644
--- a/gcc/testsuite/g++.dg/gomp/unmappable-1.C
+++ b/gcc/testsuite/g++.dg/gomp/unmappable-1.C
@@ -4,7 +4,7 @@
 class C
 {
 public:
-  static int static_member; /* { dg-message "static field .C::static_member. 
is not mappable" } */
+  static int static_member;
   virtual void f() {}
 };