1 files changed, 47 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index 5a88a8d21a5..dec06bc9cc8 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -56,6 +56,8 @@ class MIParser {
   StringMap<unsigned> Names2Regs;
   /// Maps from register mask names to register masks.
   StringMap<const uint32_t *> Names2RegMasks;
+  /// Maps from subregister names to subregister indices.
+  StringMap<unsigned> Names2SubRegIndices;
 
 public:
   MIParser(SourceMgr &SM, MachineFunction &MF, SMDiagnostic &Error,
@@ -79,6 +81,7 @@ public:
 
   bool parseRegister(unsigned &Reg);
   bool parseRegisterFlag(unsigned &Flags);
+  bool parseSubRegisterIndex(unsigned &SubReg);
   bool parseRegisterOperand(MachineOperand &Dest, bool IsDef = false);
   bool parseImmediateOperand(MachineOperand &Dest);
   bool parseMBBReference(MachineBasicBlock *&MBB);
@@ -115,6 +118,13 @@ private:
   ///
   /// Return null if the identifier isn't a register mask.
   const uint32_t *getRegMask(StringRef Identifier);
+
+  void initNames2SubRegIndices();
+
+  /// Check if the given identifier is a name of a subregister index.
+  ///
+  /// Return 0 if the name isn't a subregister index class.
+  unsigned getSubRegIndex(StringRef Name);
 };
 
 } // end anonymous namespace
@@ -332,6 +342,19 @@ bool MIParser::parseRegisterFlag(unsigned &Flags) {
   return false;
 }
 
+bool MIParser::parseSubRegisterIndex(unsigned &SubReg) {
+  assert(Token.is(MIToken::colon));
+  lex();
+  if (Token.isNot(MIToken::Identifier))
+    return error("expected a subregister index after ':'");
+  auto Name = Token.stringValue();
+  SubReg = getSubRegIndex(Name);
+  if (!SubReg)
+    return error(Twine("use of unknown subregister index '") + Name + "'");
+  lex();
+  return false;
+}
+
 bool MIParser::parseRegisterOperand(MachineOperand &Dest, bool IsDef) {
   unsigned Reg;
   unsigned Flags = IsDef ? RegState::Define : 0;
@@ -344,10 +367,15 @@ bool MIParser::parseRegisterOperand(MachineOperand &Dest, bool IsDef) {
   if (parseRegister(Reg))
     return true;
   lex();
-  // TODO: Parse subregister.
+  unsigned SubReg = 0;
+  if (Token.is(MIToken::colon)) {
+    if (parseSubRegisterIndex(SubReg))
+      return true;
+  }
   Dest = MachineOperand::CreateReg(
       Reg, Flags & RegState::Define, Flags & RegState::Implicit,
-      Flags & RegState::Kill, Flags & RegState::Dead, Flags & RegState::Undef);
+      Flags & RegState::Kill, Flags & RegState::Dead, Flags & RegState::Undef,
+      /*isEarlyClobber=*/false, SubReg);
   return false;
 }
 
@@ -525,6 +553,23 @@ const uint32_t *MIParser::getRegMask(StringRef Identifier) {
   return RegMaskInfo->getValue();
 }
 
+void MIParser::initNames2SubRegIndices() {
+  if (!Names2SubRegIndices.empty())
+    return;
+  const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
+  for (unsigned I = 1, E = TRI->getNumSubRegIndices(); I < E; ++I)
+    Names2SubRegIndices.insert(
+        std::make_pair(StringRef(TRI->getSubRegIndexName(I)).lower(), I));
+}
+
+unsigned MIParser::getSubRegIndex(StringRef Name) {
+  initNames2SubRegIndices();
+  auto SubRegInfo = Names2SubRegIndices.find(Name);
+  if (SubRegInfo == Names2SubRegIndices.end())
+    return 0;
+  return SubRegInfo->getValue();
+}
+
 bool llvm::parseMachineInstr(MachineInstr *&MI, SourceMgr &SM,
                              MachineFunction &MF, StringRef Src,
                              const PerFunctionMIParsingState &PFS,