3 files changed, 27 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/MIRParser/MILexer.cpp b/llvm/lib/CodeGen/MIRParser/MILexer.cpp
index 2a6db07bc4b..b1131615cbf 100644
--- a/llvm/lib/CodeGen/MIRParser/MILexer.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MILexer.cpp
@@ -325,6 +325,15 @@ static Cursor maybeLexConstantPoolItem(Cursor C, MIToken &Token) {
   return maybeLexIndex(C, Token, "%const.", MIToken::ConstantPoolItem);
 }
 
+static Cursor maybeLexSubRegisterIndex(Cursor C, MIToken &Token,
+                                       ErrorCallbackType ErrorCallback) {
+  const StringRef Rule = "%subreg.";
+  if (!C.remaining().startswith(Rule))
+    return None;
+  return lexName(C, Token, MIToken::SubRegisterIndex, Rule.size(),
+                 ErrorCallback);
+}
+
 static Cursor maybeLexIRBlock(Cursor C, MIToken &Token,
                               ErrorCallbackType ErrorCallback) {
   const StringRef Rule = "%ir-block.";
@@ -570,6 +579,8 @@ StringRef llvm::lexMIToken(StringRef Source, MIToken &Token,
     return R.remaining();
   if (Cursor R = maybeLexConstantPoolItem(C, Token))
     return R.remaining();
+  if (Cursor R = maybeLexSubRegisterIndex(C, Token, ErrorCallback))
+    return R.remaining();
   if (Cursor R = maybeLexIRBlock(C, Token, ErrorCallback))
     return R.remaining();
   if (Cursor R = maybeLexIRValue(C, Token, ErrorCallback))
diff --git a/llvm/lib/CodeGen/MIRParser/MILexer.h b/llvm/lib/CodeGen/MIRParser/MILexer.h
index ddf5e9f7c10..32fc8ab271e 100644
--- a/llvm/lib/CodeGen/MIRParser/MILexer.h
+++ b/llvm/lib/CodeGen/MIRParser/MILexer.h
@@ -118,7 +118,8 @@ struct MIToken {
     IRBlock,
     NamedIRValue,
     IRValue,
-    QuotedIRValue // `<constant value>`
+    QuotedIRValue, // `<constant value>`
+    SubRegisterIndex
   };
 
 private:
diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index 141aeb57349..8c7345111c5 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -144,6 +144,7 @@ public:
   bool parseGlobalValue(GlobalValue *&GV);
   bool parseGlobalAddressOperand(MachineOperand &Dest);
   bool parseConstantPoolIndexOperand(MachineOperand &Dest);
+  bool parseSubRegisterIndexOperand(MachineOperand &Dest);
   bool parseJumpTableIndexOperand(MachineOperand &Dest);
   bool parseExternalSymbolOperand(MachineOperand &Dest);
   bool parseMDNode(MDNode *&Node);
@@ -1237,6 +1238,17 @@ bool MIParser::parseExternalSymbolOperand(MachineOperand &Dest) {
   return false;
 }
 
+bool MIParser::parseSubRegisterIndexOperand(MachineOperand &Dest) {
+  assert(Token.is(MIToken::SubRegisterIndex));
+  StringRef Name = Token.stringValue();
+  unsigned SubRegIndex = getSubRegIndex(Token.stringValue());
+  if (SubRegIndex == 0)
+    return error(Twine("unknown subregister index '") + Name + "'");
+  lex();
+  Dest = MachineOperand::CreateImm(SubRegIndex);
+  return false;
+}
+
 bool MIParser::parseMDNode(MDNode *&Node) {
   assert(Token.is(MIToken::exclaim));
   auto Loc = Token.location();
@@ -1482,6 +1494,8 @@ bool MIParser::parseMachineOperand(MachineOperand &Dest,
     return parseJumpTableIndexOperand(Dest);
   case MIToken::ExternalSymbol:
     return parseExternalSymbolOperand(Dest);
+  case MIToken::SubRegisterIndex:
+    return parseSubRegisterIndexOperand(Dest);
   case MIToken::exclaim:
     return parseMetadataOperand(Dest);
   case MIToken::kw_cfi_same_value: