[ms-inline asm] Add a comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166819 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/AsmParser/X86AsmParser.cpp

@@ -756,6 +756,7 @@ X86Operand *X86AsmParser::ParseIntelBracExpression(unsigned SegReg,
   Parser.Lex();
   End = Tok.getLoc();
 
+  // Parse the dot operator (e.g., [ebx].foo.bar).
   if (Tok.getString().startswith(".")) {
     SmallString<64> Err;
     const MCExpr *NewDisp;