LivePhysRegs: Follow-up to r303937

We may have situations in which a superregister is reserved and not
added to liveins, so we have to add the subregisters.

llvm-svn: 303949

llvm/lib/CodeGen/LivePhysRegs.cpp

@@ -230,7 +230,7 @@ void llvm::computeLiveIns(LivePhysRegs &LiveRegs,
     // Skip the register if we are about to add one of its super registers.
     bool ContainsSuperReg = false;
     for (MCSuperRegIterator SReg(Reg, &TRI); SReg.isValid(); ++SReg) {
-      if (LiveRegs.contains(*SReg)) {
+      if (LiveRegs.contains(*SReg) && !MRI.isReserved(*SReg)) {
         ContainsSuperReg = true;
         break;
       }