re PR c/7543 (no warning for always-false "if (!a & 0x4)" bitwise and on boolean value)

2008-10-24  Manuel López-Ibáñez  <manu@gcc.gnu.org>

	PR c/7543
	* value-prof.c (gimple_stringop_fixed_value): Use parentheses
	around bit operation.
	* profile.c (is_edge_inconsistent): Likewise.
	* fold-const.c (truth_value_p): Move from here...
	* tree.h (truth_value_p): ... to here.
	* c-tree.h (c_expr): Update description of original_code.
	* c-typeck.c (parser_build_unary_op): Set original_code.
	(parser_build_binary_op): Update call to warn_about_parentheses.
	* c-common.c (warn_about_parentheses): Take two additional
	arguments of the operands. Use a switch. Quote operators
	appropriately. Define macro APPEARS_TO_BE_BOOLEAN_EXPR_P.
	Add warning about !x | y and !x & y.
	* c-common.h (warn_about_parentheses): Update declaration.
cp/	
	* typeck.c (build_x_binary_op): Update call to
	warn_about_parentheses.
	* parser.c (cp_parser_binary_expression): Add note about passing
	the correct code for unary expressions.
testsuite/
	* gcc.dg/Wparentheses-11.c: New.
	* g++.dg/warn/Wparentheses-25.C: New. XFAILED.

From-SVN: r141340

1 files changed, 11 insertions, 0 deletions

diff --git a/gcc/tree.h b/gcc/tree.h
index a8edda7..a85b4c6 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -4838,6 +4838,17 @@ extern bool tree_expr_nonzero_warnv_p (tree, bool *);
 
 extern bool fold_real_zero_addition_p (const_tree, const_tree, int);
 
+/* Return nonzero if CODE is a tree code that represents a truth value.  */
+static inline bool
+truth_value_p (enum tree_code code)
+{
+  return (TREE_CODE_CLASS (code) == tcc_comparison
+	  || code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
+	  || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
+	  || code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
+}
+
+
 /* In builtins.c */
 extern tree fold_call_expr (tree, bool);
 extern tree fold_builtin_fputs (tree, tree, bool, bool, tree);