1 files changed, 30 insertions, 6 deletions

diff --git a/llvm/lib/Target/Lanai/AsmParser/LanaiAsmParser.cpp b/llvm/lib/Target/Lanai/AsmParser/LanaiAsmParser.cpp
index 8b8504978c755..639ab24b08179 100644
--- a/llvm/lib/Target/Lanai/AsmParser/LanaiAsmParser.cpp
+++ b/llvm/lib/Target/Lanai/AsmParser/LanaiAsmParser.cpp
@@ -47,7 +47,7 @@ struct LanaiOperand;
 
 class LanaiAsmParser : public MCTargetAsmParser {
   // Parse operands
-  std::unique_ptr<LanaiOperand> parseRegister();
+  std::unique_ptr<LanaiOperand> parseRegister(bool RestoreOnFailure = false);
 
   std::unique_ptr<LanaiOperand> parseImmediate();
 
@@ -67,6 +67,8 @@ class LanaiAsmParser : public MCTargetAsmParser {
                         SMLoc NameLoc, OperandVector &Operands) override;
 
   bool ParseRegister(unsigned &RegNum, SMLoc &StartLoc, SMLoc &EndLoc) override;
+  OperandMatchResultTy tryParseRegister(unsigned &RegNo, SMLoc &StartLoc,
+                                        SMLoc &EndLoc) override;
 
   bool MatchAndEmitInstruction(SMLoc IdLoc, unsigned &Opcode,
                                OperandVector &Operands, MCStreamer &Out,
@@ -657,7 +659,7 @@ bool LanaiAsmParser::MatchAndEmitInstruction(SMLoc IdLoc, unsigned &Opcode,
 
   switch (MatchInstructionImpl(Operands, Inst, ErrorInfo, MatchingInlineAsm)) {
   case Match_Success:
-    Out.EmitInstruction(Inst, SubtargetInfo);
+    Out.emitInstruction(Inst, SubtargetInfo);
     Opcode = Inst.getOpcode();
     return false;
   case Match_MissingFeature:
@@ -687,21 +689,30 @@ bool LanaiAsmParser::MatchAndEmitInstruction(SMLoc IdLoc, unsigned &Opcode,
 // backwards compatible with GCC and the different ways inline assembly is
 // handled.
 // TODO: see if there isn't a better way to do this.
-std::unique_ptr<LanaiOperand> LanaiAsmParser::parseRegister() {
+std::unique_ptr<LanaiOperand>
+LanaiAsmParser::parseRegister(bool RestoreOnFailure) {
   SMLoc Start = Parser.getTok().getLoc();
   SMLoc End = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
+  Optional<AsmToken> PercentTok;
 
   unsigned RegNum;
   // Eat the '%'.
-  if (Lexer.getKind() == AsmToken::Percent)
+  if (Lexer.getKind() == AsmToken::Percent) {
+    PercentTok = Parser.getTok();
     Parser.Lex();
+  }
   if (Lexer.getKind() == AsmToken::Identifier) {
     RegNum = MatchRegisterName(Lexer.getTok().getIdentifier());
-    if (RegNum == 0)
+    if (RegNum == 0) {
+      if (PercentTok.hasValue() && RestoreOnFailure)
+        Lexer.UnLex(PercentTok.getValue());
       return nullptr;
+    }
     Parser.Lex(); // Eat identifier token
     return LanaiOperand::createReg(RegNum, Start, End);
   }
+  if (PercentTok.hasValue() && RestoreOnFailure)
+    Lexer.UnLex(PercentTok.getValue());
   return nullptr;
 }
 
@@ -710,12 +721,25 @@ bool LanaiAsmParser::ParseRegister(unsigned &RegNum, SMLoc &StartLoc,
   const AsmToken &Tok = getParser().getTok();
   StartLoc = Tok.getLoc();
   EndLoc = Tok.getEndLoc();
-  std::unique_ptr<LanaiOperand> Op = parseRegister();
+  std::unique_ptr<LanaiOperand> Op = parseRegister(/*RestoreOnFailure=*/false);
   if (Op != nullptr)
     RegNum = Op->getReg();
   return (Op == nullptr);
 }
 
+OperandMatchResultTy LanaiAsmParser::tryParseRegister(unsigned &RegNum,
+                                                      SMLoc &StartLoc,
+                                                      SMLoc &EndLoc) {
+  const AsmToken &Tok = getParser().getTok();
+  StartLoc = Tok.getLoc();
+  EndLoc = Tok.getEndLoc();
+  std::unique_ptr<LanaiOperand> Op = parseRegister(/*RestoreOnFailure=*/true);
+  if (Op == nullptr)
+    return MatchOperand_NoMatch;
+  RegNum = Op->getReg();
+  return MatchOperand_Success;
+}
+
 std::unique_ptr<LanaiOperand> LanaiAsmParser::parseIdentifier() {
   SMLoc Start = Parser.getTok().getLoc();
   SMLoc End = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);