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, 18 insertions, 1 deletions

diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index 186cb62bd2a..a4e4bc9df26 100644
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -43,6 +43,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #include "target.h"
 #include "tree-iterator.h"
 #include "tree-gimple.h"
+#include "tree-flow.h"
 
 /* Possible cases of implicit bad conversions.  Used to select
    diagnostic messages in convert_for_assignment.  */
@@ -6762,10 +6763,23 @@ c_finish_loop (location_t start_locus, tree cond, tree incr, tree body,
 tree
 c_finish_bc_stmt (tree *label_p, bool is_break)
 {
+  bool skip;
   tree label = *label_p;
 
+  /* In switch statements break is sometimes stylistically used after
+     a return statement.  This can lead to spurious warnings about
+     control reaching the end of a non-void function when it is
+     inlined.  Note that we are calling block_may_fallthru with
+     language specific tree nodes; this works because
+     block_may_fallthru returns true when given something it does not
+     understand.  */
+  skip = !block_may_fallthru (cur_stmt_list);
+
   if (!label)
-    *label_p = label = create_artificial_label ();
+    {
+      if (!skip)
+	*label_p = label = create_artificial_label ();
+    }
   else if (TREE_CODE (label) != LABEL_DECL)
     {
       if (is_break)
@@ -6775,6 +6789,9 @@ c_finish_bc_stmt (tree *label_p, bool is_break)
       return NULL_TREE;
     }
 
+  if (skip)
+    return NULL_TREE;
+
   return add_stmt (build1 (GOTO_EXPR, void_type_node, label));
 }