[llvm-branch-commits] [cfe-branch] r215651 - Document -Wtautological-pointer-compare & -Wtautological-undefined-compare with example

[Sylvestre Ledru]

Author: sylvestre
Date: Thu Aug 14 11:09:45 2014
New Revision: 215651

URL: http://llvm.org/viewvc/llvm-project?rev=215651&view=rev
Log:
Document -Wtautological-pointer-compare & -Wtautological-undefined-compare with example

Modified:
    cfe/branches/release_35/docs/ReleaseNotes.rst

Modified: cfe/branches/release_35/docs/ReleaseNotes.rst
URL: http://llvm.org/viewvc/llvm-project/cfe/branches/release_35/docs/ReleaseNotes.rst?rev=215651&r1=215650&r2=215651&view=diff
==============================================================================
--- cfe/branches/release_35/docs/ReleaseNotes.rst (original)
+++ cfe/branches/release_35/docs/ReleaseNotes.rst Thu Aug 14 11:09:45 2014
@@ -70,6 +70,38 @@ about them. The improvements since the 3
 - New warning `-Wabsolute-value`: Clang warns about incorrect or useless usage
   of the absolute functions (`abs`, `fabsf`, etc).
 
+- New warning `-Wtautological-pointer-compare`:
+
+  .. code-block:: c++
+
+    #include <stddef.h>
+    void foo() {
+     int arr[5];
+     int x;
+     // warn on these conditionals
+     if (foo);
+     if (arr);
+     if (&x);
+     if (foo == NULL);
+     if (arr == NULL);
+     if (&x == NULL);
+    }
+
+  returns
+  `warning: comparison of address of 'x' equal to a null pointer is always false [-Wtautological-pointer-compare]`
+
+- New warning `-Wtautological-undefined-compare`: 
+
+  .. code-block:: c++
+
+    #include <stddef.h>
+    void f(int &x) {
+       if (&x == nullptr) { }
+    }
+
+  returns
+  `warning: reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false [-Wtautological-undefined-compare]`
+
 -  ...
 
 New Compiler Flags