re PR c/66322 (Linus Torvalds: -Wswitch-bool produces dubious warnings, fails to notice really bad things)

	PR c/66322
	* c-common.c (check_case_bounds): Add bool * parameter.  Set
	OUTSIDE_RANGE_P.
	(c_add_case_label): Add bool * parameter.  Pass it down to
	check_case_bounds.
	(c_do_switch_warnings): Add bool parameters.  Implement -Wswitch-bool
	warning here.
	* c-common.h (c_add_case_label, c_do_switch_warnings): Update
	declarations.

	* c-typeck.c (struct c_switch): Add BOOL_COND_P and OUTSIDE_RANGE_P.
	(c_start_case): Set BOOL_COND_P and OUTSIDE_RANGE_P.  Don't warn
	about -Wswitch-bool here.
	(do_case): Update c_add_case_label call.
	(c_finish_case): Update c_do_switch_warnings call.

	* decl.c (struct cp_switch): Add OUTSIDE_RANGE_P.
	(push_switch): Set OUTSIDE_RANGE_P.
	(pop_switch): Update c_do_switch_warnings call.
	(finish_case_label): Update c_add_case_label call.
	* semantics.c (finish_switch_cond): Don't warn about -Wswitch-bool
	here.

	* function.c (stack_protect_epilogue): Remove a cast to int.
	* doc/invoke.texi: Update -Wswitch-bool description.

	* c-c++-common/pr60439.c: Add dg-prune-output and add switch cases.
	* c-c++-common/pr66322.c: New test.
	* g++.dg/eh/scope1.C: Remove dg-warning.

From-SVN: r225116

2 files changed, 26 insertions, 5 deletions

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index edba3f1..2c5ba6d 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,12 @@
+2015-06-29  Marek Polacek  <polacek@redhat.com>
+
+	PR c/66322
+	* c-typeck.c (struct c_switch): Add BOOL_COND_P and OUTSIDE_RANGE_P.
+	(c_start_case): Set BOOL_COND_P and OUTSIDE_RANGE_P.  Don't warn
+	about -Wswitch-bool here.
+	(do_case): Update c_add_case_label call.
+	(c_finish_case): Update c_do_switch_warnings call.
+
 2015-06-27  Marek Polacek  <polacek@redhat.com>
 
 	* c-typeck.c: Use VECTOR_TYPE_P throughout.
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index 8e2696a..6ea3513 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -9525,6 +9525,14 @@ struct c_switch {
 
   /* The next node on the stack.  */
   struct c_switch *next;
+
+  /* Remember whether the controlling expression had boolean type
+     before integer promotions for the sake of -Wswitch-bool.  */
+  bool bool_cond_p;
+
+  /* Remember whether there was a case value that is outside the
+     range of the ORIG_TYPE.  */
+  bool outside_range_p;
 };
 
 /* A stack of the currently active switch statements.  The innermost
@@ -9538,7 +9546,7 @@ 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.
-   EXPLICIT_CAST_P is true if the expression EXP has explicit cast.  */
+   EXPLICIT_CAST_P is true if the expression EXP has an explicit cast.  */
 
 tree
 c_start_case (location_t switch_loc,
@@ -9546,6 +9554,7 @@ c_start_case (location_t switch_loc,
 	      tree exp, bool explicit_cast_p)
 {
   tree orig_type = error_mark_node;
+  bool bool_cond_p = false;
   struct c_switch *cs;
 
   if (exp != error_mark_node)
@@ -9575,8 +9584,7 @@ c_start_case (location_t switch_loc,
 	      /* 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");
+	    bool_cond_p = true;
 
 	  if (!in_system_header_at (input_location)
 	      && (type == long_integer_type_node
@@ -9600,6 +9608,8 @@ c_start_case (location_t switch_loc,
   cs->orig_type = orig_type;
   cs->cases = splay_tree_new (case_compare, NULL, NULL);
   cs->bindings = c_get_switch_bindings ();
+  cs->bool_cond_p = bool_cond_p;
+  cs->outside_range_p = false;
   cs->next = c_switch_stack;
   c_switch_stack = cs;
 
@@ -9646,7 +9656,8 @@ do_case (location_t loc, tree low_value, tree high_value)
   label = c_add_case_label (loc, c_switch_stack->cases,
 			    SWITCH_COND (c_switch_stack->switch_expr),
 			    c_switch_stack->orig_type,
-			    low_value, high_value);
+			    low_value, high_value,
+			    &c_switch_stack->outside_range_p);
   if (label == error_mark_node)
     label = NULL_TREE;
   return label;
@@ -9667,7 +9678,8 @@ c_finish_case (tree body, tree type)
   switch_location = EXPR_LOCATION (cs->switch_expr);
   c_do_switch_warnings (cs->cases, switch_location,
 			type ? type : TREE_TYPE (cs->switch_expr),
-			SWITCH_COND (cs->switch_expr));
+			SWITCH_COND (cs->switch_expr),
+			cs->bool_cond_p, cs->outside_range_p);
 
   /* Pop the stack.  */
   c_switch_stack = cs->next;