Index: lib/Lex/Lexer.cpp
===================================================================
--- lib/Lex/Lexer.cpp	(revision 112025)
+++ lib/Lex/Lexer.cpp	(working copy)
@@ -919,6 +919,11 @@
   }
 }
 
+/// isHexaLiteral - Return true if Start points to a hex constant.
+static inline bool isHexaLiteral(const char* Start, const char* End) {
+  return ((End - Start > 2) && Start[0] == '0' && 
+          (Start[1] == 'x' || Start[1] == 'X'));
+}
 
 /// LexNumericConstant - Lex the remainder of a integer or floating point
 /// constant. From[-1] is the first character lexed.  Return the end of the
@@ -934,7 +939,11 @@
   }
 
   // If we fell out, check for a sign, due to 1e+12.  If we have one, continue.
-  if ((C == '-' || C == '+') && (PrevCh == 'E' || PrevCh == 'e'))
+  // If we are in Microsoft mode, don't continue if the constant is hex.
+  // For example, MSVC will accept the following as 3 tokens: 0x1234567e+1
+  if ((C == '-' || C == '+') && (PrevCh == 'E' || PrevCh == 'e') &&
+      (!PP || !PP->getLangOptions().Microsoft || 
+       !isHexaLiteral(BufferPtr, CurPtr)))
     return LexNumericConstant(Result, ConsumeChar(CurPtr, Size, Result));
 
   // If we have a hex FP constant, continue.
Index: test/Lexer/ms-extensions.c
===================================================================
--- test/Lexer/ms-extensions.c	(revision 112025)
+++ test/Lexer/ms-extensions.c	(working copy)
@@ -23,3 +23,11 @@
         unsigned short s = USHORT;
         unsigned char c = UCHAR;
 }
+
+void pr_7968()
+{
+  int var1 = 0x1111111e+1;
+  int var2 = 0X1111111e+1;
+  int var3 = 0xe+1;
+  int var4 = 0XE+1;
+}
\ No newline at end of file