Index: llvm/include/llvm/MC/MCParser/AsmLexer.h
===================================================================
--- llvm/include/llvm/MC/MCParser/AsmLexer.h
+++ llvm/include/llvm/MC/MCParser/AsmLexer.h
@@ -30,7 +30,6 @@
   StringRef CurBuf;
   bool IsAtStartOfLine = true;
   bool IsAtStartOfStatement = true;
-  bool IsParsingMSInlineAsm = false;
   bool IsPeeking = false;
 
 protected:
@@ -44,7 +43,6 @@
   ~AsmLexer() override;
 
   void setBuffer(StringRef Buf, const char *ptr = nullptr);
-  void setParsingMSInlineAsm(bool V) { IsParsingMSInlineAsm = V; }
 
   StringRef LexUntilEndOfStatement() override;
 
Index: llvm/include/llvm/MC/MCParser/MCAsmLexer.h
===================================================================
--- llvm/include/llvm/MC/MCParser/MCAsmLexer.h
+++ llvm/include/llvm/MC/MCParser/MCAsmLexer.h
@@ -50,6 +50,7 @@
   bool SkipSpace = true;
   bool AllowAtInIdentifier;
   bool IsAtStartOfStatement = true;
+  bool LexMasmIntegers = false;
   AsmCommentConsumer *CommentConsumer = nullptr;
 
   MCAsmLexer();
@@ -146,6 +147,10 @@
   void setCommentConsumer(AsmCommentConsumer *CommentConsumer) {
     this->CommentConsumer = CommentConsumer;
   }
+
+  /// Set whether to lex masm-style binary and hex literals. They look like
+  /// 0b1101 and 0ABCh respectively.
+  void setLexMasmIntegers(bool V) { LexMasmIntegers = V; }
 };
 
 } // end namespace llvm
Index: llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
+++ llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
@@ -156,9 +156,10 @@
   Parser->setAssemblerDialect(Dialect);
   Parser->setTargetParser(*TAP.get());
   Parser->setEnablePrintSchedInfo(EnablePrintSchedInfo);
+  // Enable lexing Masm binary and hex integer literals in intel inline
+  // assembly.
   if (Dialect == InlineAsm::AD_Intel)
-    // We need this flag to be able to parse numbers like "0bH"
-    Parser->setParsingInlineAsm(true);
+    Parser->getLexer().setLexMasmIntegers(true);
   if (MF) {
     const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
     TAP->SetFrameRegister(TRI->getFrameRegister(*MF));
Index: llvm/lib/MC/MCParser/AsmLexer.cpp
===================================================================
--- llvm/lib/MC/MCParser/AsmLexer.cpp
+++ llvm/lib/MC/MCParser/AsmLexer.cpp
@@ -281,7 +281,7 @@
 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])) {
+  if (LexMasmIntegers && isdigit(CurPtr[-1])) {
     const char *FirstNonBinary = (CurPtr[-1] != '0' && CurPtr[-1] != '1') ?
                                    CurPtr - 1 : nullptr;
     const char *OldCurPtr = CurPtr;
@@ -346,7 +346,7 @@
     return intToken(Result, Value);
   }
 
-  if (!IsParsingMSInlineAsm && ((*CurPtr == 'b') || (*CurPtr == 'B'))) {
+  if (!LexMasmIntegers && ((*CurPtr == 'b') || (*CurPtr == 'B'))) {
     ++CurPtr;
     // See if we actually have "0b" as part of something like "jmp 0b\n"
     if (!isDigit(CurPtr[0])) {
@@ -395,7 +395,7 @@
       return ReturnError(TokStart, "invalid hexadecimal number");
 
     // Consume the optional [hH].
-    if (!IsParsingMSInlineAsm && (*CurPtr == 'h' || *CurPtr == 'H'))
+    if (!LexMasmIntegers && (*CurPtr == 'h' || *CurPtr == 'H'))
       ++CurPtr;
 
     // The darwin/x86 (and x86-64) assembler accepts and ignores ULL and LL
Index: llvm/lib/MC/MCParser/AsmParser.cpp
===================================================================
--- llvm/lib/MC/MCParser/AsmParser.cpp
+++ llvm/lib/MC/MCParser/AsmParser.cpp
@@ -229,7 +229,9 @@
 
   void setParsingInlineAsm(bool V) override {
     ParsingInlineAsm = V;
-    Lexer.setParsingMSInlineAsm(V);
+    // When parsing MS inline asm, we must lex 0b1101 and 0ABCH as binary and
+    // hex integer literals.
+    Lexer.setLexMasmIntegers(V);
   }
   bool isParsingInlineAsm() override { return ParsingInlineAsm; }
 
Index: llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
===================================================================
--- llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -3283,7 +3283,6 @@
   if (IDVal.startswith(".code"))
     return ParseDirectiveCode(IDVal, DirectiveID.getLoc());
   else if (IDVal.startswith(".att_syntax")) {
-    getParser().setParsingInlineAsm(false);
     if (getLexer().isNot(AsmToken::EndOfStatement)) {
       if (Parser.getTok().getString() == "prefix")
         Parser.Lex();
@@ -3296,7 +3295,6 @@
     return false;
   } else if (IDVal.startswith(".intel_syntax")) {
     getParser().setAssemblerDialect(1);
-    getParser().setParsingInlineAsm(true);
     if (getLexer().isNot(AsmToken::EndOfStatement)) {
       if (Parser.getTok().getString() == "noprefix")
         Parser.Lex();
Index: llvm/test/MC/X86/pr27884.s
===================================================================
--- llvm/test/MC/X86/pr27884.s
+++ llvm/test/MC/X86/pr27884.s
@@ -1,4 +1,4 @@
-// RUN: llvm-mc -triple x86_64-unknown-unknown %s
+// RUN: llvm-mc -triple x86_64-unknown-unknown %s -masm-integers=1
 
 .intel_syntax
 add rbx, 0B0h
Index: llvm/tools/llvm-mc/llvm-mc.cpp
===================================================================
--- llvm/tools/llvm-mc/llvm-mc.cpp
+++ llvm/tools/llvm-mc/llvm-mc.cpp
@@ -164,6 +164,10 @@
 static cl::opt<bool> SaveTempLabels("save-temp-labels",
                                     cl::desc("Don't discard temporary labels"));
 
+static cl::opt<bool> LexMasmIntegers(
+    "masm-integers",
+    cl::desc("Enable binary and hex masm integers (0b110 and 0ABCh)"));
+
 static cl::opt<bool> NoExecStack("no-exec-stack",
                                  cl::desc("File doesn't need an exec stack"));
 
@@ -293,6 +297,7 @@
     return SymbolResult;
   Parser->setShowParsedOperands(ShowInstOperands);
   Parser->setTargetParser(*TAP);
+  Parser->getLexer().setLexMasmIntegers(LexMasmIntegers);
 
   int Res = Parser->Run(NoInitialTextSection);