Index: cfe/trunk/tools/clang-format/clang-format-diff.py
===================================================================
--- cfe/trunk/tools/clang-format/clang-format-diff.py
+++ cfe/trunk/tools/clang-format/clang-format-diff.py
@@ -43,8 +43,8 @@
                       help='custom pattern selecting file paths to reformat '
                       '(case sensitive, overrides -iregex)')
   parser.add_argument('-iregex', metavar='PATTERN', default=
-                      r'.*\.(cpp|cc|c\+\+|cxx|c|cl|h|hpp|m|mm|inc|js|ts|proto'
-                      r'|protodevel|java)',
+                      r'.*\.(cpp|cc|c\+\+|cxx|c|cl|h|hh|hpp|m|mm|inc|js|ts|proto'
+                      r'|protodevel|java|cs)',
                       help='custom pattern selecting file paths to reformat '
                       '(case insensitive, overridden by -regex)')
   parser.add_argument('-sort-includes', action='store_true', default=False,
Index: cfe/trunk/tools/clang-format/git-clang-format
===================================================================
--- cfe/trunk/tools/clang-format/git-clang-format
+++ cfe/trunk/tools/clang-format/git-clang-format
@@ -77,13 +77,14 @@
       'c', 'h',  # C
       'm',  # ObjC
       'mm',  # ObjC++
-      'cc', 'cp', 'cpp', 'c++', 'cxx', 'hpp', 'hxx',  # C++
+      'cc', 'cp', 'cpp', 'c++', 'cxx', 'hh', 'hpp', 'hxx',  # C++
       'cu',  # CUDA
       # Other languages that clang-format supports
       'proto', 'protodevel',  # Protocol Buffers
       'java',  # Java
       'js',  # JavaScript
       'ts',  # TypeScript
+      'cs',  # C Sharp
       ])
 
   p = argparse.ArgumentParser(