diff --git a/docs/ProgrammersManual.rst b/docs/ProgrammersManual.rst
index 44f76fef8f1..665e30aeb67 100644
--- a/docs/ProgrammersManual.rst
+++ b/docs/ProgrammersManual.rst
@@ -408,6 +408,9 @@ Then you can run your pass like this:
   'foo' debug type
   $ opt < a.bc > /dev/null -mypass -debug-only=bar
   'bar' debug type
+  $ opt < a.bc > /dev/null -mypass -debug-only=foo,bar
+  'foo' debug type
+  'bar' debug type
 
 Of course, in practice, you should only set ``DEBUG_TYPE`` at the top of a file,
 to specify the debug type for the entire module. Be careful that you only do
@@ -417,7 +420,8 @@ system in place to ensure that names do not conflict. If two different modules
 use the same string, they will all be turned on when the name is specified.
 This allows, for example, all debug information for instruction scheduling to be
 enabled with ``-debug-only=InstrSched``, even if the source lives in multiple
-files.
+files. The name must not include a comma (,) as that is used to seperate the
+arguments of the ``-debug-only`` option.
 
 For performance reasons, -debug-only is not available in optimized build
 (``--enable-optimized``) of LLVM.
diff --git a/lib/Support/Debug.cpp b/lib/Support/Debug.cpp
index 47751fce3fc..323d53279b4 100644
--- a/lib/Support/Debug.cpp
+++ b/lib/Support/Debug.cpp
@@ -95,7 +95,10 @@ struct DebugOnlyOpt {
     if (Val.empty())
       return;
     DebugFlag = true;
-    CurrentDebugType->push_back(Val);
+    SmallVector<StringRef,8> dbgTypes;
+    StringRef(Val).split(dbgTypes, ',', -1, false);
+    for (auto dbgType : dbgTypes)
+      CurrentDebugType->push_back(dbgType);
   }
 };
 
@@ -104,10 +107,9 @@ struct DebugOnlyOpt {
 static DebugOnlyOpt DebugOnlyOptLoc;
 
 static cl::opt<DebugOnlyOpt, true, cl::parser<std::string> >
-DebugOnly("debug-only", cl::desc("Enable a specific type of debug output"),
+DebugOnly("debug-only", cl::desc("Enable a specific type of debug output (comma separated list of types)"),
           cl::Hidden, cl::ZeroOrMore, cl::value_desc("debug string"),
           cl::location(DebugOnlyOptLoc), cl::ValueRequired);
-
 // Signal handlers - dump debug output on termination.
 static void debug_user_sig_handler(void *Cookie) {
   // This is a bit sneaky.  Since this is under #ifndef NDEBUG, we