c-common.c (maybe_warn_bool_compare): When comparing with 0/1, require that the…

c-common.c (maybe_warn_bool_compare): When comparing with 0/1, require that the non-constant be of a boolean type.

	* c-common.c (maybe_warn_bool_compare): When comparing with 0/1,
	require that the non-constant be of a boolean type.

	* c-c++-common/Wbool-compare-3.c: New test.

From-SVN: r222622

gcc/c-family/ChangeLog

+2015-04-30  Marek Polacek  <polacek@redhat.com>
+
+	* c-common.c (maybe_warn_bool_compare): When comparing with 0/1,
+	require that the non-constant be of a boolean type.
+
 2015-04-29  Josh Triplett  <josh@joshtriplett.org>
 
         * c-common.c (handle_section_attribute): Refactor to reduce

gcc/c-family/c-common.c

@@ -11924,6 +11924,17 @@ maybe_warn_bool_compare (location_t loc, enum tree_code code, tree op0,
     }
   else if (integer_zerop (cst) || integer_onep (cst))
     {
+      /* If the non-constant operand isn't of a boolean type, we
+	 don't want to warn here.  */
+      tree noncst = TREE_CODE (op0) == INTEGER_CST ? op1 : op0;
+      /* Handle booleans promoted to integers.  */
+      if (CONVERT_EXPR_P (noncst)
+	  && TREE_TYPE (noncst) == integer_type_node
+	  && TREE_CODE (TREE_TYPE (TREE_OPERAND (noncst, 0))) == BOOLEAN_TYPE)
+	/* Warn.  */;
+      else if (TREE_CODE (TREE_TYPE (noncst)) != BOOLEAN_TYPE
+	       && !truth_value_p (TREE_CODE (noncst)))
+	return;
       /* Do some magic to get the right diagnostics.  */
       bool flag = TREE_CODE (op0) == INTEGER_CST;
       flag = integer_zerop (cst) ? flag : !flag;

gcc/testsuite/ChangeLog

+2015-04-30  Marek Polacek  <polacek@redhat.com>
+
+	* c-c++-common/Wbool-compare-3.c: New test.
+
 2015-04-30  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/57610

gcc/testsuite/c-c++-common/Wbool-compare-3.c

+/* { dg-do compile } */
+/* { dg-options "-Wbool-compare" } */
+
+#ifndef __cplusplus
+# define bool _Bool
+#endif
+
+#define A 0
+#define B 1
+
+int
+foo (int i, bool b)
+{
+  int r = 0;
+
+  r += i <= (A || B);
+  r += i <= b;
+  r += i <= A;
+  r += i < (A || B);
+  r += i < b;
+  r += i < A;
+  r += i > (A || B);
+  r += i > b;
+  r += i > A;
+  r += i >= (A || B);
+  r += i >= b;
+  r += i >= A;
+
+  return r;
+}