c-typeck.c (build_binary_op): Warn ordered comparison of pointer with null pointer and also warn about...

gcc/
2010-05-07  Shujing Zhao  <pearly.zhao@oracle.com>

        * c-typeck.c (build_binary_op): Warn ordered comparison of pointer
        with null pointer and also warn about ordered comparison of zero
        with pointer if -Wextra.

gcc/testsuite/
2010-05-07  Shujing Zhao  <pearly.zhao@oracle.com>

        * gcc.dg/ordered-comparison-1.c: New test.
        * gcc.dg/ordered-comparison-2.c: New test.
        * gcc.dg/ordered-comparison-3.c: New test.
        * gcc.dg/ordered-comparison-4.c: New test.

From-SVN: r159145

7 files changed, 109 insertions, 3 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5839779..f1885a9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2010-05-07  Shujing Zhao  <pearly.zhao@oracle.com>
+
+	* c-typeck.c (build_binary_op): Warn ordered comparison of pointer
+	with null pointer and also warn about ordered comparison of zero with
+	pointer if -Wextra.
+
 2010-05-05  Andreas Simbuerger  <simbuerg@fim.uni-passau.de>
 
 	* graphite-blocking.c
diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index 96b2ab1..2f66d6a 100644
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -9625,6 +9625,11 @@ build_binary_op (location_t location, enum tree_code code,
 	      else if (TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
 		pedwarn (location, OPT_pedantic, "ISO C forbids "
 			 "ordered comparisons of pointers to functions");
+	      else if (null_pointer_constant_p (orig_op0)
+		       || null_pointer_constant_p (orig_op1))
+		warning_at (location, OPT_Wextra,
+			    "ordered comparison of pointer with null pointer");
+
 	    }
 	  else if (!addr_space_superset (as0, as1, &as_common))
 	    {
@@ -9649,13 +9654,17 @@ build_binary_op (location_t location, enum tree_code code,
 		     "ordered comparison of pointer with integer zero");
 	  else if (extra_warnings)
 	    warning_at (location, OPT_Wextra,
-		     "ordered comparison of pointer with integer zero");
+			"ordered comparison of pointer with integer zero");
 	}
       else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
 	{
 	  result_type = type1;
-	  pedwarn (location, OPT_pedantic,
-		   "ordered comparison of pointer with integer zero");
+	  if (pedantic)
+	    pedwarn (location, OPT_pedantic,
+		     "ordered comparison of pointer with integer zero");
+	  else if (extra_warnings)
+	    warning_at (location, OPT_Wextra,
+			"ordered comparison of pointer with integer zero");
 	}
       else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
 	{
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1377bcb..50397ef 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2010-05-07  Shujing Zhao  <pearly.zhao@oracle.com>
+
+	* gcc.dg/ordered-comparison-1.c: New test.
+	* gcc.dg/ordered-comparison-2.c: New test.
+	* gcc.dg/ordered-comparison-3.c: New test.
+	* gcc.dg/ordered-comparison-4.c: New test.
+
 2010-05-06  Mike Stump  <mikestump@comcast.net>
 
 	PR objc/35165
diff --git a/gcc/testsuite/gcc.dg/ordered-comparison-1.c b/gcc/testsuite/gcc.dg/ordered-comparison-1.c
new file mode 100644
index 0000000..0131c9d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ordered-comparison-1.c
@@ -0,0 +1,21 @@
+/* Test warning for ordered comparison pointer with null pointer constant. */
+/* Tested with no warning option. */
+/* { dg-do compile } */
+/* { dg-options "" } */
+extern void z();
+void *p;
+
+void f() {
+ if (z >= 0)
+   z();
+ if (0 >= z)
+    z();
+ if (p >= (void*)0)
+    z();
+ if ((void*)0 >= p)
+    z();
+ if (z >= (void*)0) /* { dg-warning "distinct pointer types lacks a cast" } */
+    z();
+ if ((void*)0 >=z) /* { dg-warning "distinct pointer types lacks a cast" } */
+    z();
+}
diff --git a/gcc/testsuite/gcc.dg/ordered-comparison-2.c b/gcc/testsuite/gcc.dg/ordered-comparison-2.c
new file mode 100644
index 0000000..a99d9c3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ordered-comparison-2.c
@@ -0,0 +1,21 @@
+/* Test warning for ordered comparison pointer with null pointer constant. */
+/* Tested with -pedantic. */
+/* { dg-do compile } */
+/* { dg-options "-pedantic" } */
+extern void z();
+void *p;
+
+void f() {
+ if (z >= 0) /* { dg-warning "ordered comparison of pointer with" } */
+   z();
+ if (0 >= z) /* { dg-warning "ordered comparison of pointer with" } */
+    z();
+ if (p >= (void*)0)
+    z();
+ if ((void*)0 >= p)
+    z();
+ if (z >= (void*)0) /* { dg-warning "distinct pointer types lacks a cast" } */
+    z();
+ if ((void*)0 >=z) /* { dg-warning "distinct pointer types lacks a cast" } */
+    z();
+}
diff --git a/gcc/testsuite/gcc.dg/ordered-comparison-3.c b/gcc/testsuite/gcc.dg/ordered-comparison-3.c
new file mode 100644
index 0000000..2e4be49
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ordered-comparison-3.c
@@ -0,0 +1,21 @@
+/* Test warning for ordered comparison pointer with null pointer constant. */
+/* Test with -pedantic-errors. */
+/* { dg-do compile } */
+/* { dg-options "-pedantic-errors" } */
+extern void z();
+void *p;
+
+void f() {
+ if ( z >= 0 ) /* { dg-error "ordered comparison of pointer with" } */
+   z();
+ if ( 0 >= z) /* { dg-error "ordered comparison of pointer with" } */
+    z();
+ if ( p >= (void*)0 )
+    z();
+ if ( (void*)0 >= p)
+    z();
+ if (z >= (void*)0) /* { dg-error "distinct pointer types lacks a cast" } */
+    z();
+ if ((void*)0 >=z) /* { dg-error "distinct pointer types lacks a cast" } */
+    z(); 
+}
diff --git a/gcc/testsuite/gcc.dg/ordered-comparison-4.c b/gcc/testsuite/gcc.dg/ordered-comparison-4.c
new file mode 100644
index 0000000..ebe9edd
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ordered-comparison-4.c
@@ -0,0 +1,21 @@
+/* Test warning for ordered comparison pointer with null pointer constant. */
+/* Test with -Wextra. */
+/* { dg-do compile } */
+/* { dg-options "-Wextra" } */
+extern void z();
+void *p;
+
+void f() {
+ if (z >= 0) /* { dg-warning "ordered comparison of pointer with" } */
+   z();
+ if (0 >= z) /* { dg-warning "ordered comparison of pointer with" } */
+    z();
+ if (p >= (void*)0) /* { dg-warning "ordered comparison of pointer with null pointer" } */
+    z();
+ if ((void*)0 >= p) /* { dg-warning "ordered comparison of pointer with null pointer" } */
+    z();
+ if (z >= (void*)0) /* { dg-warning "distinct pointer types lacks a cast" } */
+    z();
+ if ((void*)0 >=z) /* { dg-warning "distinct pointer types lacks a cast" } */
+    z();
+}