re PR c++/11957 (wrong "warning: statement has no effect")

cp:
	PR c++/11957
	* cp-tree.h (finish_stmt_expr): Add bool parameter.
	* init.c (finish_init_stmts): Pass true to finish_stmt_expr. Don't
	adjust the stmt_expr here.
	(build_vec_init): Use finish_stmt_expr_expr, convert result to
	array type.
	* parser.c (cp_parser_primar_expression): Adjust finish_stmt_expr
	call.
	* pt.c (tsubst_copy): Likewise.
	* semantics.c (finish_stmt_expr): Add parameter.
testsuite:
	PR c++/11957
	* g++.dg/warn/noeffect1.C: New test.

From-SVN: r70541

gcc/cp/ChangeLog

@@ -1,5 +1,16 @@
 2003-08-18  Nathan Sidwell  <nathan@codesourcery.com>
 
+	PR c++/11957
+	* cp-tree.h (finish_stmt_expr): Add bool parameter.
+	* init.c (finish_init_stmts): Pass true to finish_stmt_expr. Don't
+	adjust the stmt_expr here.
+	(build_vec_init): Use finish_stmt_expr_expr, convert result to
+	array type.
+	* parser.c (cp_parser_primar_expression): Adjust finish_stmt_expr
+	call.
+	* pt.c (tsubst_copy): Likewise.
+	* semantics.c (finish_stmt_expr): Add parameter.
+
 	* pt.c (instantiate_class_template): Push to class's scope before
 	tsubsting base.
 

gcc/cp/cp-tree.h

@@ -4102,7 +4102,7 @@ extern tree finish_parenthesized_expr           (tree);
 extern tree finish_non_static_data_member       (tree, tree, tree);
 extern tree begin_stmt_expr                     (void);
 extern tree finish_stmt_expr_expr 		(tree);
-extern tree finish_stmt_expr                    (tree);
+extern tree finish_stmt_expr                    (tree, bool);
 extern tree perform_koenig_lookup               (tree, tree);
 extern tree finish_call_expr                    (tree, tree, bool);
 extern tree finish_increment_expr               (tree, enum tree_code);

gcc/cp/init.c

@@ -85,9 +85,7 @@ finish_init_stmts (bool is_global, tree stmt_expr, tree compound_stmt)
 {  
   finish_compound_stmt (compound_stmt);
   
-  stmt_expr = finish_stmt_expr (stmt_expr);
-  STMT_EXPR_NO_SCOPE (stmt_expr) = true;
-  TREE_USED (stmt_expr) = 1;
+  stmt_expr = finish_stmt_expr (stmt_expr, true);
 
   my_friendly_assert (!building_stmt_tree () == is_global, 20030726);
   
@@ -2478,7 +2476,7 @@ build_vec_init (tree base, tree maxindex, tree init, int from_array)
     base = cp_convert (ptype, decay_conversion (base));
 
   /* The code we are generating looks like:
-
+     ({
        T* t1 = (T*) base;
        T* rval = t1;
        ptrdiff_t iterator = maxindex;
@@ -2490,7 +2488,8 @@ build_vec_init (tree base, tree maxindex, tree init, int from_array)
        } catch (...) {
          ... destroy elements that were constructed ...
        }
-       return rval;
+       rval;
+     })
        
      We can omit the try and catch blocks if we know that the
      initialization will never throw an exception, or if the array
@@ -2662,18 +2661,22 @@ build_vec_init (tree base, tree maxindex, tree init, int from_array)
 
       finish_compound_stmt (try_body);
       finish_cleanup_try_block (try_block);
-      e = build_vec_delete_1 (rval, m,
-			      type,
-			      sfk_base_destructor,
+      e = build_vec_delete_1 (rval, m, type, sfk_base_destructor,
 			      /*use_global_delete=*/0);
       finish_cleanup (e, try_block);
     }
 
-  /* The value of the array initialization is the address of the
-     first element in the array.  */
-  finish_expr_stmt (rval);
+  /* The value of the array initialization is the array itself, RVAL
+     is a pointer to the first element.  */
+  finish_stmt_expr_expr (rval);
 
   stmt_expr = finish_init_stmts (is_global, stmt_expr, compound_stmt);
+
+  /* Now convert make the result have the correct type. */
+  atype = build_pointer_type (atype);
+  stmt_expr = build1 (NOP_EXPR, atype, stmt_expr);
+  stmt_expr = build_indirect_ref (stmt_expr, NULL);
+  
   current_stmt_tree ()->stmts_are_full_exprs_p = destroy_temps;
   return stmt_expr;
 }

gcc/cp/parser.c

@@ -2270,7 +2270,7 @@ cp_parser_primary_expression (cp_parser *parser,
 	    /* Parse the compound-statement.  */
 	    cp_parser_compound_statement (parser, true);
 	    /* Finish up.  */
-	    expr = finish_stmt_expr (expr);
+	    expr = finish_stmt_expr (expr, false);
 	  }
 	else
 	  {

gcc/cp/pt.c

@@ -7343,7 +7343,7 @@ tsubst_copy (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 	  
 	  tsubst_expr (STMT_EXPR_STMT (t), args,
 		       complain | tf_stmt_expr_cmpd, in_decl);
-	  return finish_stmt_expr (stmt_expr);
+	  return finish_stmt_expr (stmt_expr, false);
 	}
       
       return t;

gcc/cp/semantics.c

@@ -1405,7 +1405,7 @@ begin_stmt_expr (void)
   last_expr_type = NULL_TREE;
   
   keep_next_level (1);
-  
+
   return last_tree; 
 }
 
@@ -1469,13 +1469,12 @@ finish_stmt_expr_expr (tree expr)
   return result;
 }
 
-/* Finish a statement-expression.  RTL_EXPR should be the value
-   returned by the previous begin_stmt_expr; EXPR is the
-   statement-expression.  Returns an expression representing the
-   statement-expression.  */
+/* Finish a statement-expression.  EXPR should be the value returned
+   by the previous begin_stmt_expr.  Returns an expression
+   representing the statement-expression.  */
 
 tree 
-finish_stmt_expr (tree rtl_expr)
+finish_stmt_expr (tree rtl_expr, bool has_no_scope)
 {
   tree result;
   tree result_stmt = last_expr_type;
@@ -1496,6 +1495,7 @@ finish_stmt_expr (tree rtl_expr)
   
   result = build_min (STMT_EXPR, type, last_tree);
   TREE_SIDE_EFFECTS (result) = 1;
+  STMT_EXPR_NO_SCOPE (result) = has_no_scope;
   
   last_expr_type = NULL_TREE;