ms inline asm: Don't add x86 segment registers to the clobber list.

Clang tries to check the clobber list but doesn't list segment registers in its
x86 register list. This fixes PR20343.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213303 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/AsmParser/X86AsmParser.cpp

@@ -696,6 +696,8 @@ private:
                                unsigned &ErrorInfo,
                                bool MatchingInlineAsm) override;
 
+  virtual bool OmitRegisterFromClobberLists(unsigned RegNo) override;
+
   /// doSrcDstMatch - Returns true if operands are matching in their
   /// word size (%si and %di, %esi and %edi, etc.). Order depends on
   /// the parsing mode (Intel vs. AT&T).
@@ -2520,6 +2522,9 @@ bool X86AsmParser::MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
   return true;
 }
 
+bool X86AsmParser::OmitRegisterFromClobberLists(unsigned RegNo) {
+  return X86MCRegisterClasses[X86::SEGMENT_REGRegClassID].contains(RegNo);
+}
 
 bool X86AsmParser::ParseDirective(AsmToken DirectiveID) {
   StringRef IDVal = DirectiveID.getIdentifier();