re PR c/77292 (Spurious warning: logical not is only applied to the left hand side of comparison)

	PR c/77292
	* c-common.c (warn_logical_not_parentheses): Don't warn for
	a comparison or a logical operator.

	* c-c++-common/Wlogical-not-parentheses-1.c: New test.

From-SVN: r239833

gcc/c-family/ChangeLog

+2016-08-29  Marek Polacek  <polacek@redhat.com>
+
+	PR c/77292
+	* c-common.c (warn_logical_not_parentheses): Don't warn for
+	a comparison or a logical operator.
+
 2016-08-29  Tom de Vries  <tom@codesourcery.com>
 
 	* c-common.c (build_va_arg): Fix type comparison assert.

gcc/c-family/c-common.c

@@ -1481,7 +1481,8 @@ warn_tautological_cmp (location_t loc, enum tree_code code, tree lhs, tree rhs)
 
 /* Warn about logical not used on the left hand side operand of a comparison.
    This function assumes that the LHS is inside of TRUTH_NOT_EXPR.
-   Do not warn if RHS is of a boolean type.  */
+   Do not warn if RHS is of a boolean type, a logical operator, or
+   a comparison.  */
 
 void
 warn_logical_not_parentheses (location_t location, enum tree_code code,
@@ -1489,7 +1490,8 @@ warn_logical_not_parentheses (location_t location, enum tree_code code,
 {
   if (TREE_CODE_CLASS (code) != tcc_comparison
       || TREE_TYPE (rhs) == NULL_TREE
-      || TREE_CODE (TREE_TYPE (rhs)) == BOOLEAN_TYPE)
+      || TREE_CODE (TREE_TYPE (rhs)) == BOOLEAN_TYPE
+      || truth_value_p (TREE_CODE (rhs)))
     return;
 
   /* Don't warn for !x == 0 or !y != 0, those are equivalent to

gcc/testsuite/ChangeLog

+2016-08-29  Marek Polacek  <polacek@redhat.com>
+
+	PR c/77292
+	* c-c++-common/Wlogical-not-parentheses-1.c: New test.
+
 2016-08-29  Tom de Vries  <tom@codesourcery.com>
 
 	PR c/77398

gcc/testsuite/c-c++-common/Wlogical-not-parentheses-1.c

+/* PR c/77292 */
+/* { dg-do compile } */
+/* { dg-options "-Wlogical-not-parentheses" } */
+
+ /* Test that we don't warn if rhs is a comparison or a logical op.  */
+
+int
+foo (int a, int b)
+{
+  int r = 0;
+  r += !a == (a < b);
+  r += !a == (a > b);
+  r += !a == (a >= b);
+  r += !a == (a <= b);
+  r += !a == (a != b);
+  r += !a == (a == b);
+  r += !a == (a || b);
+  r += !a == (a && b);
+  r += !a == (!b);
+
+  r += !a == (a ^ b); /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  r += !a == (a | b); /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  r += !a == (a & b); /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+
+  return r;
+}