diff --git a/lib/Target/SystemZ/SystemZRegisterInfo.cpp b/lib/Target/SystemZ/SystemZRegisterInfo.cpp
index 28f94f4b6c6..18b82f3a6cf 100644
--- a/lib/Target/SystemZ/SystemZRegisterInfo.cpp
+++ b/lib/Target/SystemZ/SystemZRegisterInfo.cpp
@@ -58,6 +58,20 @@ BitVector SystemZRegisterInfo::getReservedRegs(const MachineFunction &MF) const
   return Reserved;
 }
 
+const TargetRegisterClass*
+SystemZRegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
+                                              const TargetRegisterClass *B,
+                                              unsigned Idx) const {
+  switch(Idx) {
+  // Exact sub-classes don't exist for the other sub-register indexes.
+  default: return 0;
+  case SystemZ::subreg_32bit:
+    if (B == SystemZ::ADDR32RegisterClass)
+      return A->getSize() == 8 ? SystemZ::ADDR64RegisterClass : 0;
+    return A;
+  }
+}
+
 void SystemZRegisterInfo::
 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
                               MachineBasicBlock::iterator I) const {
diff --git a/lib/Target/SystemZ/SystemZRegisterInfo.h b/lib/Target/SystemZ/SystemZRegisterInfo.h
index b45079889a2..6379fd3510b 100644
--- a/lib/Target/SystemZ/SystemZRegisterInfo.h
+++ b/lib/Target/SystemZ/SystemZRegisterInfo.h
@@ -34,6 +34,10 @@ struct SystemZRegisterInfo : public SystemZGenRegisterInfo {
 
   BitVector getReservedRegs(const MachineFunction &MF) const;
 
+  const TargetRegisterClass*
+  getMatchingSuperRegClass(const TargetRegisterClass *A,
+                           const TargetRegisterClass *B, unsigned Idx) const;
+
   void eliminateCallFramePseudoInstr(MachineFunction &MF,
                                      MachineBasicBlock &MBB,
                                      MachineBasicBlock::iterator I) const;