tree.h (expand_expr_stmt_value): Add maybe_last argument.

	* tree.h (expand_expr_stmt_value): Add maybe_last argument.
	* c-common.h (genrtl_expr_stmt_value): Likewise.
	* stmt.c (expand_expr_stmt): Pass 1 as maybe_last.
	(expand_expr_stmt_value): Add maybe_last argument.
	Don't warn about statement with no effect if it is the last statement
	in expression statement.
	* c-semantics.c (genrtl_expr_stmt): Pass 1 as maybe_last.
	(genrtl_expr_stmt_value): Add maybe_last argument, pass it down to
	expand_expr_stmt_value.
	(expand_stmt) [EXPR_STMT]: Pass 1 as maybe_last to
	genrtl_expr_stmt_value if t is the last EXPR_STMT in its scope.
	* expr.c (expand_expr) [LABELED_BLOCK_EXPR, LOOP_EXPR]: Pass 1
	as maybe_last to expand_expr_stmt_value.

	* gcc.dg/20020104-1.c: New test.

From-SVN: r48541

1 files changed, 7 insertions, 5 deletions

diff --git a/gcc/stmt.c b/gcc/stmt.c
index 16a3882..6933599 100644
--- a/gcc/stmt.c
+++ b/gcc/stmt.c
@@ -2190,7 +2190,7 @@ void
 expand_expr_stmt (exp)
      tree exp;
 {
-  expand_expr_stmt_value (exp, -1);
+  expand_expr_stmt_value (exp, -1, 1);
 }
 
 /* Generate RTL to evaluate the expression EXP.  WANT_VALUE tells
@@ -2199,9 +2199,9 @@ expand_expr_stmt (exp)
    deprecated, and retained only for backward compatibility.  */
 
 void
-expand_expr_stmt_value (exp, want_value)
+expand_expr_stmt_value (exp, want_value, maybe_last)
      tree exp;
-     int want_value;
+     int want_value, maybe_last;
 {
   rtx value;
   tree type;
@@ -2211,8 +2211,10 @@ expand_expr_stmt_value (exp, want_value)
 
   /* If -W, warn about statements with no side effects,
      except for an explicit cast to void (e.g. for assert()), and
-     except inside a ({...}) where they may be useful.  */
-  if (! want_value && exp != error_mark_node)
+     except for last statement in ({...}) where they may be useful.  */
+  if (! want_value
+      && (expr_stmts_for_value == 0 || ! maybe_last)
+      && exp != error_mark_node)
     {
       if (! TREE_SIDE_EFFECTS (exp))
 	{