diff --git a/lib/Lex/LiteralSupport.cpp b/lib/Lex/LiteralSupport.cpp
index 3b739b3..2eabd7e 100644
--- a/lib/Lex/LiteralSupport.cpp
+++ b/lib/Lex/LiteralSupport.cpp
@@ -431,6 +431,7 @@
       }
       continue;  // Success.
     case 'i':
+    case 'I':
       if (PP.getLangOptions().Microsoft) {
         if (isFPConstant || isLong || isLongLong) break;
 
@@ -467,7 +468,6 @@
         }
       }
       // fall through.
-    case 'I':
     case 'j':
     case 'J':
       if (isImaginary) break;   // Cannot be repeated.
diff --git a/test/Lexer/ms-extensions.c b/test/Lexer/ms-extensions.c
index 8b7d2e1..9cd868e 100644
--- a/test/Lexer/ms-extensions.c
+++ b/test/Lexer/ms-extensions.c
@@ -4,6 +4,7 @@
 __int16 x2 = 4i16;
 __int32 x3 = 5i32;
 __int64 x5 = 0x42i64;
+__int64 x6 = 0x42I64;
 __int64 x4 = 70000000i128;
 
 __int64 y = 0x42i64u;  // expected-error {{invalid suffix}}