re PR c/60439 (No warning for case overflow in switch statement.)

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.

From-SVN: r211194

gcc/ChangeLog

@@ -1,4 +1,13 @@
-2014-06-03  Vishnu K S <Vishnu.k_s@atmel.com>
+2014-06-03  Marek Polacek  <polacek@redhat.com>
+
+	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.
+
+2014-06-03  Vishnu K S  <Vishnu.k_s@atmel.com>
 
 	* config/avr/avr-mcus.def: Add new avr25 devices attiny441, attiny828
 	and attiny841.
@@ -6,8 +15,8 @@
 	* config/avr/t-multilib: Regenerate.
 	* doc/avr-mmcu.texi: Regenerate.
 
-2014-06-03  Vishnu K S <vishnu.k_s@atmel.com>
-	    Pitchumani Sivanupandi <pitchumani.s@atmel.com>
+2014-06-03  Vishnu K S  <vishnu.k_s@atmel.com>
+	    Pitchumani Sivanupandi  <pitchumani.s@atmel.com>
 
 	* config/avr/avr-mcus.def (ata6616c): Add new avr25 device.
 	(ata6617c, ata664251): Add new avr35 devices.

gcc/c-family/ChangeLog

@@ -1,3 +1,8 @@
+2014-06-03  Marek Polacek  <polacek@redhat.com>
+
+	PR c/60439
+	* c.opt (Wswitch-bool): New option.
+
 2014-05-22  Thomas Schwinge  <thomas@codesourcery.com>
 
 	* c-common.h (c_omp_sharing_predetermined, c_omp_remap_decl):

gcc/c-family/c.opt

@@ -534,6 +534,10 @@ Wswitch-enum
 C ObjC C++ ObjC++ Var(warn_switch_enum) Warning
 Warn about all enumerated switches missing a specific case
 
+Wswitch-bool
+C ObjC C++ ObjC++ Warning Init(1)
+Warn about switches with boolean controlling expression
+
 Wmissing-format-attribute
 C ObjC C++ ObjC++ Alias(Wsuggest-attribute=format)
 ;

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.

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);

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);

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

gcc/cp/ChangeLog

@@ -1,3 +1,9 @@
+2014-06-03  Marek Polacek  <polacek@redhat.com>
+
+	PR c/60439
+	* semantics.c (finish_switch_cond): Warn if switch condition has
+	boolean value.
+
 2014-06-03  Jason Merrill  <jason@redhat.com>
 
 	PR c++/60992

gcc/cp/semantics.c

@@ -1130,6 +1130,11 @@ finish_switch_cond (tree cond, tree switch_stmt)
       orig_type = TREE_TYPE (cond);
       if (cond != error_mark_node)
 	{
+	  /* Warn if the condition has boolean value.  */
+	  if (TREE_CODE (orig_type) == BOOLEAN_TYPE)
+	    warning_at (input_location, OPT_Wswitch_bool,
+			"switch condition has type bool");
+
 	  /* [stmt.switch]
 
 	     Integral promotions are performed.  */

gcc/doc/invoke.texi

@@ -271,7 +271,7 @@ Objective-C and Objective-C++ Dialects}.
 -Wstrict-aliasing=n @gol -Wstrict-overflow -Wstrict-overflow=@var{n} @gol
 -Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{]} @gol
 -Wmissing-format-attribute @gol
--Wswitch  -Wswitch-default  -Wswitch-enum -Wsync-nand @gol
+-Wswitch  -Wswitch-default  -Wswitch-enum -Wswitch-bool -Wsync-nand @gol
 -Wsystem-headers  -Wtrampolines  -Wtrigraphs  -Wtype-limits  -Wundef @gol
 -Wuninitialized  -Wunknown-pragmas  -Wno-pragmas @gol
 -Wunsuffixed-float-constants  -Wunused  -Wunused-function @gol
@@ -3846,6 +3846,22 @@ between @option{-Wswitch} and this option is that this option gives a
 warning about an omitted enumeration code even if there is a
 @code{default} label.
 
+@item -Wswitch-bool
+@opindex Wswitch-bool
+@opindex Wno-switch-bool
+Warn whenever a @code{switch} statement has an index of boolean type.
+It is possible to suppress this warning by casting the controlling
+expression to a type other than @code{bool}.  For example:
+@smallexample
+@group
+switch ((int) (a == 4))
+  @{
+  ...
+  @}
+@end group
+@end smallexample
+This warning is enabled by default for C and C++ programs.
+
 @item -Wsync-nand @r{(C and C++ only)}
 @opindex Wsync-nand
 @opindex Wno-sync-nand

gcc/function.c

@@ -4649,7 +4649,7 @@ stack_protect_epilogue (void)
 
   /* Allow the target to compare Y with X without leaking either into
      a register.  */
-  switch (HAVE_stack_protect_test != 0)
+  switch ((int) (HAVE_stack_protect_test != 0))
     {
     case 1:
       tmp = gen_stack_protect_test (x, y, label);

gcc/gengtype.c

@@ -3099,9 +3099,9 @@ walk_type (type_p t, struct walk_type_data *d)
 			       t->u.s.tag);
 		desc = "1";
 	      }
-	    oprintf (d->of, "%*sswitch (", d->indent, "");
+	    oprintf (d->of, "%*sswitch ((int) (", d->indent, "");
 	    output_escaped_param (d, desc, "desc");
-	    oprintf (d->of, ")\n");
+	    oprintf (d->of, "))\n");
 	    d->indent += 2;
 	    oprintf (d->of, "%*s{\n", d->indent, "");
 	  }
@@ -3121,9 +3121,9 @@ walk_type (type_p t, struct walk_type_data *d)
 			       "missing `tag' option for type `%s'",
 			       t->u.s.tag);
 	      }
-	    oprintf (d->of, "%*sswitch (", d->indent, "");
+	    oprintf (d->of, "%*sswitch ((int) (", d->indent, "");
 	    output_escaped_param (d, desc, "desc");
-	    oprintf (d->of, ")\n");
+	    oprintf (d->of, "))\n");
 	    d->indent += 2;
 	    oprintf (d->of, "%*s{\n", d->indent, "");
 	    oprintf (d->of, "%*scase %s:\n", d->indent, "", type_tag);

gcc/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2014-06-03  Marek Polacek  <polacek@redhat.com>
+
+	PR c/60439
+	* c-c++-common/pr60439.c: New test.
+	* g++.dg/eh/scope1.C (f4): Add dg-warning.
+
 2014-06-03  Martin Jambor  <mjambor@suse.cz>
 
 	PR ipa/61160

gcc/testsuite/c-c++-common/pr60439.c

@@ -0,0 +1,108 @@
+/* PR c/60439 */
+/* { dg-do compile } */
+
+#ifndef __cplusplus
+# define bool _Bool
+#endif
+
+extern bool foo (void);
+
+void
+f1 (bool b)
+{
+  switch (b) /* { dg-warning "switch condition has" } */
+    break;
+}
+
+void
+f2 (int a, int b)
+{
+  switch (a && b) /* { dg-warning "switch condition has" } */
+    break;
+  switch ((bool) (a && b)) /* { dg-warning "switch condition has" } */
+    break;
+  switch ((a && b) || a) /* { dg-warning "switch condition has" } */
+    break;
+  /* No warnings on following.  */
+  switch ((int) (a && b))
+    break;
+  switch ((unsigned int) (a && b))
+    break;
+  switch ((unsigned short int) (a && b))
+    break;
+  switch ((char) (a && b))
+    break;
+}
+
+void
+f3 (int a)
+{
+  switch (!!a) /* { dg-warning "switch condition has" } */
+    break;
+  switch (!a) /* { dg-warning "switch condition has" } */
+    break;
+}
+
+void
+f4 (void)
+{
+  switch (foo ()) /* { dg-warning "switch condition has" } */
+    break;
+}
+
+void
+f5 (int a)
+{
+  switch (a == 3) /* { dg-warning "switch condition has" } */
+    break;
+  switch (a != 3) /* { dg-warning "switch condition has" } */
+    break;
+  switch (a > 3) /* { dg-warning "switch condition has" } */
+    break;
+  switch (a < 3) /* { dg-warning "switch condition has" } */
+    break;
+  switch (a <= 3) /* { dg-warning "switch condition has" } */
+    break;
+  switch (a >= 3) /* { dg-warning "switch condition has" } */
+    break;
+  switch (foo (), foo (), a >= 42) /* { dg-warning "switch condition has" } */
+    break;
+  switch (a == 3, a & 4, a ^ 5, a)
+    break;
+  switch ((int) (a == 3))
+    break;
+  switch ((int) (a != 3))
+    break;
+}
+
+void
+f6 (bool b)
+{
+  switch (b) /* { dg-warning "switch condition has" } */
+    break;
+  switch (!b) /* { dg-warning "switch condition has" } */
+    break;
+  switch (b++) /* { dg-warning "switch condition has" } */
+    break;
+}
+
+void
+f7 (void)
+{
+  bool b;
+  switch (b = 1) /* { dg-warning "switch condition has" } */
+    break;
+}
+
+void
+f8 (int i)
+{
+  switch (i)
+    break;
+  switch ((int) i)
+    break;
+  switch ((unsigned int) i)
+    break;
+  switch ((bool) i) /* { dg-warning "switch condition has" } */
+    break;
+}

gcc/testsuite/g++.dg/eh/scope1.C

@@ -31,7 +31,7 @@ void f3 ()
 
 void f4 ()
 {
-  switch (C br = C())
+  switch (C br = C()) /* { dg-warning "switch condition has" } */
     {
     default:
       abort ();