re PR c/65120 (Wlogical-not-parentheses should not warn about double exclamation !!)

	PR c/65120
	* c-common.c (warn_logical_not_parentheses): Don't warn for
	!x == 0 or !x != 0.

	* c-typeck.c (parser_build_binary_op): Check for tcc_comparison
	before preparing arguments to warn_logical_not_parentheses.

	* parser.c (cp_parser_binary_expression): Check for tcc_comparison
	before preparing arguments to warn_logical_not_parentheses.
	Use maybe_constant_value on rhs.

	* c-c++-common/pr49706.c (fn2): Don't expect warning if enumerator
	on rhs is 0.
	(fn4): New test.
	* c-c++-common/pr65120.c: New test.

From-SVN: r221299

9 files changed, 93 insertions, 3 deletions

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 6bd5a28..3420c96 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,9 @@
+2015-03-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/65120
+	* c-common.c (warn_logical_not_parentheses): Don't warn for
+	!x == 0 or !x != 0.
+
 2015-03-07  Marek Polacek  <polacek@redhat.com>
 
 	PR sanitizer/65280
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 8c23e09..7e84eb1 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -1800,6 +1800,12 @@ warn_logical_not_parentheses (location_t location, enum tree_code code,
       || TREE_CODE (TREE_TYPE (rhs)) == BOOLEAN_TYPE)
     return;
 
+  /* Don't warn for !x == 0 or !y != 0, those are equivalent to
+     !(x == 0) or !(y != 0).  */
+  if ((code == EQ_EXPR || code == NE_EXPR)
+      && integer_zerop (rhs))
+    return;
+
   warning_at (location, OPT_Wlogical_not_parentheses,
 	      "logical not is only applied to the left hand side of "
 	      "comparison");
diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 7b81080..c15b86f 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,9 @@
+2015-03-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/65120
+	* c-typeck.c (parser_build_binary_op): Check for tcc_comparison
+	before preparing arguments to warn_logical_not_parentheses.
+
 2015-03-09  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/65120
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index 98bff32..ebe4c73 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -3459,6 +3459,7 @@ parser_build_binary_op (location_t location, enum tree_code code,
 			   code1, arg1.value, code2, arg2.value);
 
   if (warn_logical_not_paren
+      && TREE_CODE_CLASS (code) == tcc_comparison
       && code1 == TRUTH_NOT_EXPR
       && code2 != TRUTH_NOT_EXPR
       /* Avoid warning for !!x == y.  */
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 67aa184..d354e07 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2015-03-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/65120
+	* parser.c (cp_parser_binary_expression): Check for tcc_comparison
+	before preparing arguments to warn_logical_not_parentheses.
+	Use maybe_constant_value on rhs.
+
 2015-03-09  Jason Merrill  <jason@redhat.com>
 
 	PR c++/65339
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 2a3578f..ad132b1 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -8270,6 +8270,7 @@ cp_parser_binary_expression (cp_parser* parser, bool cast_p,
 	c_inhibit_evaluation_warnings -= current.lhs == truthvalue_true_node;
 
       if (warn_logical_not_paren
+	  && TREE_CODE_CLASS (current.tree_type) == tcc_comparison
 	  && current.lhs_type == TRUTH_NOT_EXPR
 	  /* Avoid warning for !!x == y.  */
 	  && (TREE_CODE (current.lhs) != NE_EXPR
@@ -8284,7 +8285,8 @@ cp_parser_binary_expression (cp_parser* parser, bool cast_p,
 	  && (!DECL_P (current.lhs)
 	      || TREE_TYPE (current.lhs) == NULL_TREE
 	      || TREE_CODE (TREE_TYPE (current.lhs)) != BOOLEAN_TYPE))
-	warn_logical_not_parentheses (current.loc, current.tree_type, rhs);
+	warn_logical_not_parentheses (current.loc, current.tree_type,
+				      maybe_constant_value (rhs));
 
       overload = NULL;
       /* ??? Currently we pass lhs_type == ERROR_MARK and rhs_type ==
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6c9ae2c..8c087ed 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,11 @@
 2015-03-10  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c/65120
+	* c-c++-common/pr49706.c (fn2): Don't expect warning if enumerator
+	on rhs is 0.
+	(fn4): New test.
+	* c-c++-common/pr65120.c: New test.
+
 	PR rtl-optimization/65321
 	* gcc.dg/pr65321.c: New test.
 
diff --git a/gcc/testsuite/c-c++-common/pr49706.c b/gcc/testsuite/c-c++-common/pr49706.c
index f41fa8b..56272ad 100644
--- a/gcc/testsuite/c-c++-common/pr49706.c
+++ b/gcc/testsuite/c-c++-common/pr49706.c
@@ -107,9 +107,9 @@ fn2 (enum E e)
   b = foo_e () == A;
   b = foo_e () == foo_e ();
 
-  b = !e == A; /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  b = !e == A;
   b = !e == foo_e (); /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
-  b = !foo_e () == A; /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  b = !foo_e () == A;
   b = !foo_e () == foo_e (); /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
 
   b = !(e == A);
@@ -163,3 +163,27 @@ fn3 (int i1, float f2)
   b = !!i1 <= f2; /* { dg-bogus "logical not is only applied to the left hand side of comparison" } */
   b = !!i1 >= f2; /* { dg-bogus "logical not is only applied to the left hand side of comparison" } */
 }
+
+void
+fn4 (enum E e)
+{
+  b = e == A;
+  b = e == foo_e ();
+  b = foo_e () == B;
+  b = foo_e () == foo_e ();
+
+  b = !e == B; /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  b = !e == foo_e (); /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  b = !foo_e () == B; /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  b = !foo_e () == foo_e (); /* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+
+  b = !(e == B);
+  b = !(e == foo_e ());
+  b = !(foo_e () == B);
+  b = !(foo_e () == foo_e ());
+
+  b = (!e) == B;
+  b = (!e) == foo_e ();
+  b = (!foo_e ()) == B;
+  b = (!foo_e ()) == foo_e ();
+}
diff --git a/gcc/testsuite/c-c++-common/pr65120.c b/gcc/testsuite/c-c++-common/pr65120.c
new file mode 100644
index 0000000..c9c1f5f
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr65120.c
@@ -0,0 +1,32 @@
+/* { dg-do compile } */
+/* { dg-options "-Wlogical-not-parentheses" } */
+
+/* Test that we don't warn if rhs is 0 and comparison is == or !=.  */
+
+#ifndef __cplusplus
+#define bool _Bool
+#endif
+
+bool r;
+
+int
+f1 (int a)
+{
+  r = !a == 0;
+  r = !a != 0;
+  r = !a == 1;	/* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  r = !a != 1;	/* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+}
+
+int
+f2 (int a)
+{
+  r = !a > 0;	/* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  r = !a >= 0;	/* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  r = !a < 0;	/* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  r = !a <= 0;	/* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  r = !a > 1;	/* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  r = !a >= 1;	/* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  r = !a < 1;	/* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+  r = !a <= 1;	/* { dg-warning "logical not is only applied to the left hand side of comparison" } */
+}