PR tree-optimization/13000

	* tree-inline.c: Include "tree-flow.h".
	(expand_call_inline): If warn_return_type, warn if non-void inline
	function falls through.
	* tree-cfg.c (execute_warn_function_return): Don't warn about
	control reaching end if TREE_NO_WARNING is set.  Set
	TREE_NO_WARNING.
	* gimple-low.c (block_may_fallthru): Don't assume that SWITCH_EXPR
	has been lowered.
	* gimplify.c (shortcut_cond_expr): Don't emit a jump over the else
	branch if we don't need one.
	* c-typeck.c: Include "tree-flow.h"
	(c_finish_bc_stmt): Don't add a goto if the current statement
	list doesn't fall through to the current point.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@94024 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 7 insertions, 1 deletions

diff --git a/gcc/gimple-low.c b/gcc/gimple-low.c
index eb495288eee..17ba0393c25 100644
--- a/gcc/gimple-low.c
+++ b/gcc/gimple-low.c
@@ -278,11 +278,17 @@ block_may_fallthru (tree block)
     case GOTO_EXPR:
     case RETURN_EXPR:
     case RESX_EXPR:
-    case SWITCH_EXPR:
       /* Easy cases.  If the last statement of the block implies 
 	 control transfer, then we can't fall through.  */
       return false;
 
+    case SWITCH_EXPR:
+      /* If SWITCH_LABELS is set, this is lowered, and represents a
+	 branch to a selected label and hence can not fall through.
+	 Otherwise SWITCH_BODY is set, and the switch can fall
+	 through.  */
+      return SWITCH_LABELS (stmt) != NULL_TREE;
+
     case COND_EXPR:
       if (block_may_fallthru (COND_EXPR_THEN (stmt)))
 	return true;