PR c/60439

	* doc/invoke.texi: Document -Wswitch-bool.
	* function.c (stack_protect_epilogue): Cast controlling expression of
	the switch to int.
	* gengtype.c (walk_type): Generate switch expression with its
	controlling expression cast to int.
c/
	* c-parser.c (c_parser_switch_statement): Pass explicit_cast_p to
	c_start_case.
	* c-tree.h (c_start_case): Update.
	* c-typeck.c (c_start_case): Add new boolean parameter.  Warn if
	switch condition has boolean value.
cp/
	* semantics.c (finish_switch_cond): Warn if switch condition has
	boolean value.
c-family/
	* c.opt (Wswitch-bool): New option.
testsuite/
	* c-c++-common/pr60439.c: New test.
	* g++.dg/eh/scope1.C (f4): Add dg-warning.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@211194 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 31 insertions, 4 deletions

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 536e07e38d9..1047a65b636 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,12 @@
+2014-06-03  Marek Polacek  <polacek@redhat.com>
+
+	PR c/60439
+	* c-parser.c (c_parser_switch_statement): Pass explicit_cast_p to
+	c_start_case.
+	* c-tree.h (c_start_case): Update.
+	* c-typeck.c (c_start_case): Add new boolean parameter.  Warn if
+	switch condition has boolean value.
+
 2014-06-02  Andrew MacLeod  <amacleod@redhat.com>
 
 	* c-decl.c: Include builtins.h.
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 1d9780edf4e..abd636c5436 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -5197,9 +5197,13 @@ c_parser_switch_statement (c_parser *parser)
   gcc_assert (c_parser_next_token_is_keyword (parser, RID_SWITCH));
   c_parser_consume_token (parser);
   block = c_begin_compound_stmt (flag_isoc99);
+  bool explicit_cast_p = false;
   if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
     {
       switch_cond_loc = c_parser_peek_token (parser)->location;
+      if (c_parser_next_token_is (parser, CPP_OPEN_PAREN)
+	  && c_token_starts_typename (c_parser_peek_2nd_token (parser)))
+	explicit_cast_p = true;
       ce = c_parser_expression (parser);
       ce = convert_lvalue_to_rvalue (switch_cond_loc, ce, true, false);
       expr = ce.value;
@@ -5217,7 +5221,7 @@ c_parser_switch_statement (c_parser *parser)
       switch_cond_loc = UNKNOWN_LOCATION;
       expr = error_mark_node;
     }
-  c_start_case (switch_loc, switch_cond_loc, expr);
+  c_start_case (switch_loc, switch_cond_loc, expr, explicit_cast_p);
   save_break = c_break_label;
   c_break_label = NULL_TREE;
   body = c_parser_c99_block_statement (parser);
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index e7dcb355e9c..133930f4a09 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -614,7 +614,7 @@ extern void process_init_element (location_t, struct c_expr, bool,
 				  struct obstack *);
 extern tree build_compound_literal (location_t, tree, tree, bool);
 extern void check_compound_literal_type (location_t, struct c_type_name *);
-extern tree c_start_case (location_t, location_t, tree);
+extern tree c_start_case (location_t, location_t, tree, bool);
 extern void c_finish_case (tree);
 extern tree build_asm_expr (location_t, tree, tree, tree, tree, tree, bool);
 extern tree build_asm_stmt (tree, tree);
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index 6ca584bf38c..a98ce0786f3 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -9361,12 +9361,13 @@ struct c_switch *c_switch_stack;
 
 /* Start a C switch statement, testing expression EXP.  Return the new
    SWITCH_EXPR.  SWITCH_LOC is the location of the `switch'.
-   SWITCH_COND_LOC is the location of the switch's condition.  */
+   SWITCH_COND_LOC is the location of the switch's condition.
+   EXPLICIT_CAST_P is true if the expression EXP has explicit cast.  */
 
 tree
 c_start_case (location_t switch_loc,
 	      location_t switch_cond_loc,
-	      tree exp)
+	      tree exp, bool explicit_cast_p)
 {
   tree orig_type = error_mark_node;
   struct c_switch *cs;
@@ -9387,6 +9388,19 @@ c_start_case (location_t switch_loc,
       else
 	{
 	  tree type = TYPE_MAIN_VARIANT (orig_type);
+	  tree e = exp;
+
+	  /* Warn if the condition has boolean value.  */
+	  while (TREE_CODE (e) == COMPOUND_EXPR)
+	    e = TREE_OPERAND (e, 1);
+
+	  if ((TREE_CODE (type) == BOOLEAN_TYPE
+	       || truth_value_p (TREE_CODE (e)))
+	      /* Explicit cast to int suppresses this warning.  */
+	      && !(TREE_CODE (type) == INTEGER_TYPE
+		   && explicit_cast_p))
+	    warning_at (switch_cond_loc, OPT_Wswitch_bool,
+			"switch condition has boolean value");
 
 	  if (!in_system_header_at (input_location)
 	      && (type == long_integer_type_node