Index: llvm/trunk/include/llvm/MC/MCParser/AsmLexer.h
===================================================================
--- llvm/trunk/include/llvm/MC/MCParser/AsmLexer.h
+++ llvm/trunk/include/llvm/MC/MCParser/AsmLexer.h
@@ -31,6 +31,7 @@
   StringRef CurBuf;
   bool IsAtStartOfLine;
   bool IsAtStartOfStatement;
+  bool IsParsingMSInlineAsm;
 
   void operator=(const AsmLexer&) = delete;
   AsmLexer(const AsmLexer&) = delete;
@@ -44,6 +45,7 @@
   ~AsmLexer() override;
 
   void setBuffer(StringRef Buf, const char *ptr = nullptr);
+  void setParsingMSInlineAsm(bool V) { IsParsingMSInlineAsm = V; }
 
   StringRef LexUntilEndOfStatement() override;
 
Index: llvm/trunk/lib/MC/MCParser/AsmLexer.cpp
===================================================================
--- llvm/trunk/lib/MC/MCParser/AsmLexer.cpp
+++ llvm/trunk/lib/MC/MCParser/AsmLexer.cpp
@@ -33,6 +33,7 @@
   CurPtr = nullptr;
   IsAtStartOfLine = true;
   IsAtStartOfStatement = true;
+  IsParsingMSInlineAsm = false;
   AllowAtInIdentifier = !StringRef(MAI.getCommentString()).startswith("@");
 }
 
@@ -264,6 +265,45 @@
 ///   Hex integer: 0x[0-9a-fA-F]+ or [0x]?[0-9][0-9a-fA-F]*[hH]
 ///   Decimal integer: [1-9][0-9]*
 AsmToken AsmLexer::LexDigit() {
+  // MASM-flavor binary integer: [01]+[bB]
+  // MASM-flavor hexadecimal integer: [0-9][0-9a-fA-F]*[hH]
+  if (IsParsingMSInlineAsm && isdigit(CurPtr[-1])) {
+    const char *FirstNonBinary = (CurPtr[-1] != '0' && CurPtr[-1] != '1') ?
+                                   CurPtr - 1 : nullptr;
+    const char *OldCurPtr = CurPtr;
+    while (isxdigit(*CurPtr)) {
+      if (*CurPtr != '0' && *CurPtr != '1' && !FirstNonBinary)
+        FirstNonBinary = CurPtr;
+      ++CurPtr;
+    }
+
+    unsigned Radix = 0;
+    if (*CurPtr == 'h' || *CurPtr == 'H') {
+      // hexadecimal number
+      ++CurPtr;
+      Radix = 16;
+    } else if (FirstNonBinary && FirstNonBinary + 1 == CurPtr &&
+               (*FirstNonBinary == 'b' || *FirstNonBinary == 'B'))
+      Radix = 2;
+
+    if (Radix == 2 || Radix == 16) {
+      StringRef Result(TokStart, CurPtr - TokStart);
+      APInt Value(128, 0, true);
+
+      if (Result.drop_back().getAsInteger(Radix, Value))
+        return ReturnError(TokStart, Radix == 2 ? "invalid binary number" :
+                             "invalid hexdecimal number");
+
+      // MSVC accepts and ignores type suffices on integer literals.
+      SkipIgnoredIntegerSuffix(CurPtr);
+
+      return intToken(Result, Value);
+   }
+
+    // octal/decimal integers, or floating point numbers, fall through
+    CurPtr = OldCurPtr;
+  }
+
   // Decimal integer: [1-9][0-9]*
   if (CurPtr[-1] != '0' || CurPtr[0] == '.') {
     unsigned Radix = doLookAhead(CurPtr, 10);
@@ -292,7 +332,7 @@
     return intToken(Result, Value);
   }
 
-  if ((*CurPtr == 'b') || (*CurPtr == 'B')) {
+  if (!IsParsingMSInlineAsm && ((*CurPtr == 'b') || (*CurPtr == 'B'))) {
     ++CurPtr;
     // See if we actually have "0b" as part of something like "jmp 0b\n"
     if (!isdigit(CurPtr[0])) {
@@ -341,7 +381,7 @@
       return ReturnError(TokStart, "invalid hexadecimal number");
 
     // Consume the optional [hH].
-    if (*CurPtr == 'h' || *CurPtr == 'H')
+    if (!IsParsingMSInlineAsm && (*CurPtr == 'h' || *CurPtr == 'H'))
       ++CurPtr;
 
     // The darwin/x86 (and x86-64) assembler accepts and ignores ULL and LL
Index: llvm/trunk/lib/MC/MCParser/AsmParser.cpp
===================================================================
--- llvm/trunk/lib/MC/MCParser/AsmParser.cpp
+++ llvm/trunk/lib/MC/MCParser/AsmParser.cpp
@@ -256,7 +256,10 @@
 
   const AsmToken &Lex() override;
 
-  void setParsingInlineAsm(bool V) override { ParsingInlineAsm = V; }
+  void setParsingInlineAsm(bool V) override {
+    ParsingInlineAsm = V;
+    Lexer.setParsingMSInlineAsm(V);
+  }
   bool isParsingInlineAsm() override { return ParsingInlineAsm; }
 
   bool parseMSInlineAsm(void *AsmLoc, std::string &AsmString,