diff --git a/llvm/Makefile.rules b/llvm/Makefile.rules
index ddd6a1c34361..01489a570f29 100644
--- a/llvm/Makefile.rules
+++ b/llvm/Makefile.rules
@@ -681,13 +681,13 @@ ifeq ($(HOST_OS),HP-UX)
   CompileCommonOpts := -D_REENTRANT -D_HPUX_SOURCE
 endif
 
-# If we are building a universal binary on Mac OS/X, pass extra options.  This
+# If we are building a universal binary on Mac OS X, pass extra options.  This
 # is useful to people that want to link the LLVM libraries into their universal
 # apps.
 #
 # The following can be optionally specified:
 #   UNIVERSAL_SDK_PATH variable can be specified as a path to the SDK to use.
-#      For Mac OS/X 10.4 Intel machines, the traditional one is:
+#      For Mac OS X 10.4 Intel machines, the traditional one is:
 #      UNIVERSAL_SDK_PATH=/Developer/SDKs/MacOSX10.4u.sdk/
 #   UNIVERSAL_ARCH can be optionally specified to be a list of architectures
 #      to build for, e.g. UNIVERSAL_ARCH="i386 ppc ppc64".  This defaults to
diff --git a/llvm/docs/ProgrammersManual.rst b/llvm/docs/ProgrammersManual.rst
index 4862611c09c6..9f388cc63f5c 100644
--- a/llvm/docs/ProgrammersManual.rst
+++ b/llvm/docs/ProgrammersManual.rst
@@ -475,8 +475,8 @@ these functions in your code in places you want to debug.
 
 Getting this to work requires a small amount of configuration.  On Unix systems
 with X11, install the `graphviz <http://www.graphviz.org>`_ toolkit, and make
-sure 'dot' and 'gv' are in your path.  If you are running on Mac OS/X, download
-and install the Mac OS/X `Graphviz program
+sure 'dot' and 'gv' are in your path.  If you are running on Mac OS X, download
+and install the Mac OS X `Graphviz program
 <http://www.pixelglow.com/graphviz/>`_ and add
 ``/Applications/Graphviz.app/Contents/MacOS/`` (or wherever you install it) to
 your path.  Once in your system and path are set up, rerun the LLVM configure
diff --git a/llvm/include/llvm/Analysis/LibCallSemantics.h b/llvm/include/llvm/Analysis/LibCallSemantics.h
index f5a9e96cbdd0..0f0bc23e00b7 100644
--- a/llvm/include/llvm/Analysis/LibCallSemantics.h
+++ b/llvm/include/llvm/Analysis/LibCallSemantics.h
@@ -27,7 +27,7 @@ namespace llvm {
   /// standard libm functions.  The location that they may be interested in is
   /// an abstract location that represents errno for the current target.  In
   /// this case, a location for errno is anything such that the predicate
-  /// returns true.  On Mac OS/X, this predicate would return true if the
+  /// returns true.  On Mac OS X, this predicate would return true if the
   /// pointer is the result of a call to "__error()".
   ///
   /// Locations can also be defined in a constant-sensitive way.  For example,
diff --git a/llvm/lib/Target/TargetLibraryInfo.cpp b/llvm/lib/Target/TargetLibraryInfo.cpp
index 46cce8485916..063151601b89 100644
--- a/llvm/lib/Target/TargetLibraryInfo.cpp
+++ b/llvm/lib/Target/TargetLibraryInfo.cpp
@@ -379,7 +379,7 @@ static void initialize(TargetLibraryInfo &TLI, const Triple &T,
   }
 #endif // !NDEBUG
   
-  // memset_pattern16 is only available on iOS 3.0 and Mac OS/X 10.5 and later.
+  // memset_pattern16 is only available on iOS 3.0 and Mac OS X 10.5 and later.
   if (T.isMacOSX()) {
     if (T.isMacOSXVersionLT(10, 5))
       TLI.setUnavailable(LibFunc::memset_pattern16);
diff --git a/llvm/projects/sample/Makefile.llvm.rules b/llvm/projects/sample/Makefile.llvm.rules
index 545e629cf34c..0ec2b2e69b89 100644
--- a/llvm/projects/sample/Makefile.llvm.rules
+++ b/llvm/projects/sample/Makefile.llvm.rules
@@ -576,13 +576,13 @@ ifeq ($(HOST_OS),HP-UX)
   CompileCommonOpts := -D_REENTRANT -D_HPUX_SOURCE
 endif
 
-# If we are building a universal binary on Mac OS/X, pass extra options.  This
+# If we are building a universal binary on Mac OS X, pass extra options.  This
 # is useful to people that want to link the LLVM libraries into their universal
 # apps.
 #
 # The following can be optionally specified:
 #   UNIVERSAL_SDK_PATH variable can be specified as a path to the SDK to use.
-#      For Mac OS/X 10.4 Intel machines, the traditional one is:
+#      For Mac OS X 10.4 Intel machines, the traditional one is:
 #      UNIVERSAL_SDK_PATH=/Developer/SDKs/MacOSX10.4u.sdk/
 #   UNIVERSAL_ARCH can be optionally specified to be a list of architectures
 #      to build for, e.g. UNIVERSAL_ARCH="i386 ppc ppc64".  This defaults to