[PATCH, C++] Wrap OpenACC wait in EXPR_STMT

[Chung-Lin Tang]

The OpenACC wait directive is represented as a call to the runtime
function "GOACC_wait" instead of a tree code.  I am seeing when
'#pragma acc wait' is using inside a template function, the CALL_EXPR
to GOACC_wait is being silently ignored/removed during tsubst_expr().

I think the correct way to organize this is that the call should be inside
an EXPR_STMT, so here's a patch to do that; basically remove the
add_stmt() call from the shared c_finish_oacc_wait() code, and add
add_stmt()/finish_expr_stmt() in the corresponding C/C++ parts.

Tested with no regressions on trunk, okay to commit?

Thanks,
Chung-Lin

        * c-family/c-omp.c (c_finish_oacc_wait): Remove add_stmt() call.
        * c/c-parser.c (c_parser_oacc_wait): Add add_stmt() call.
        * cp/parser.c (cp_parser_oacc_wait): Add finish_expr_stmt() call.

Index: c-family/c-omp.c
===================================================================
--- c-family/c-omp.c    (revision 230703)
+++ c-family/c-omp.c    (working copy)
@@ -63,7 +63,6 @@ c_finish_oacc_wait (location_t loc, tree parms, tr
     }
 
   stmt = build_call_expr_loc_vec (loc, stmt, args);
-  add_stmt (stmt);
 
   vec_free (args);
 
Index: c/c-parser.c
===================================================================
--- c/c-parser.c        (revision 230703)
+++ c/c-parser.c        (working copy)
@@ -13886,6 +13886,7 @@ c_parser_oacc_wait (location_t loc, c_parser *pars
   strcpy (p_name, " wait");
   clauses = c_parser_oacc_all_clauses (parser, OACC_WAIT_CLAUSE_MASK, p_name);
   stmt = c_finish_oacc_wait (loc, list, clauses);
+  add_stmt (stmt);
 
   return stmt;
 }
Index: cp/parser.c
===================================================================
--- cp/parser.c (revision 230703)
+++ cp/parser.c (working copy)
@@ -34930,6 +34930,7 @@ cp_parser_oacc_wait (cp_parser *parser, cp_token *
                                        "#pragma acc wait", pragma_tok);
 
   stmt = c_finish_oacc_wait (loc, list, clauses);
+  stmt = finish_expr_stmt (stmt);
 
   return stmt;
 }