diff --git a/.clang-tidy b/.clang-tidy
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -7,11 +7,11 @@
   - key:             readability-identifier-naming.FunctionCase
     value:           camelBack
   - key:             readability-identifier-naming.MemberCase
-    value:           CamelCase
+    value:           camelBack
   - key:             readability-identifier-naming.ParameterCase
-    value:           CamelCase
+    value:           camelBack
   - key:             readability-identifier-naming.UnionCase
     value:           CamelCase
   - key:             readability-identifier-naming.VariableCase
-    value:           CamelCase
+    value:           camelBack
 
diff --git a/clang/.clang-tidy b/clang/.clang-tidy
--- a/clang/.clang-tidy
+++ b/clang/.clang-tidy
@@ -12,11 +12,11 @@
   - key:             readability-identifier-naming.FunctionCase
     value:           camelBack
   - key:             readability-identifier-naming.MemberCase
-    value:           CamelCase
+    value:           camelBack
   - key:             readability-identifier-naming.ParameterCase
-    value:           CamelCase
+    value:           camelBack
   - key:             readability-identifier-naming.UnionCase
     value:           CamelCase
   - key:             readability-identifier-naming.VariableCase
-    value:           CamelCase
+    value:           camelBack
 
diff --git a/llvm/.clang-tidy b/llvm/.clang-tidy
--- a/llvm/.clang-tidy
+++ b/llvm/.clang-tidy
@@ -7,11 +7,11 @@
   - key:             readability-identifier-naming.FunctionCase
     value:           camelBack
   - key:             readability-identifier-naming.MemberCase
-    value:           CamelCase
+    value:           camelBack
   - key:             readability-identifier-naming.ParameterCase
-    value:           CamelCase
+    value:           camelBack
   - key:             readability-identifier-naming.UnionCase
     value:           CamelCase
   - key:             readability-identifier-naming.VariableCase
-    value:           CamelCase
+    value:           camelBack
 
diff --git a/llvm/docs/CodingStandards.rst b/llvm/docs/CodingStandards.rst
--- a/llvm/docs/CodingStandards.rst
+++ b/llvm/docs/CodingStandards.rst
@@ -1191,8 +1191,9 @@
   nouns and start with an upper-case letter (e.g. ``TextFileReader``).
 
 * **Variable names** should be nouns (as they represent state).  The name should
-  be camel case, and start with an upper case letter (e.g. ``Leader`` or
-  ``Boats``).
+  be camel case, and start with a lower case letter (e.g. ``leader`` or
+  ``boats``). It is also acceptable to use ``UpperCamelCase`` for consistency
+  with existing code.
   
 * **Function names** should be verb phrases (as they represent actions), and
   command-like function should be imperative.  The name should be camel case,
@@ -1232,16 +1233,22 @@
 
   class VehicleMaker {
     ...
-    Factory<Tire> F;            // Bad -- abbreviation and non-descriptive.
-    Factory<Tire> Factory;      // Better.
-    Factory<Tire> TireFactory;  // Even better -- if VehicleMaker has more than one
-                                // kind of factories.
+    Factory<Tire> f;            // Bad -- abbreviation and non-descriptive.
+    Factory<Tire> factory;      // Better.
+    Factory<Tire> tireFactory;  // Even better -- if VehicleMaker has more than
+                                // one kind of factory.
   };
 
-  Vehicle makeVehicle(VehicleType Type) {
-    VehicleMaker M;                         // Might be OK if having a short life-span.
-    Tire Tmp1 = M.makeTire();               // Bad -- 'Tmp1' provides no information.
-    Light Headlight = M.makeLight("head");  // Good -- descriptive.
+  Vehicle makeVehicle(VehicleType type) {
+    // Reusing the type name in lowerCamelCase form is often a good way to get
+    // a suitable variable name.
+    VehicleMaker vehicleMaker;
+
+    // Bad -- 'tmp1' provides no information.
+    Tire tmp1 = vehicleMaker.makeTire();
+
+    // Good -- descriptive.
+    Light headlight = vehicleMaker.makeLight("head");
     ...
   }