[mips][dsp] Fix use without def on DSPCtrl registers read by rddsp intrinsic.

Reviewers: sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: http://reviews.llvm.org/D21063

llvm-svn: 272647
diff --git a/llvm/lib/Target/Mips/MipsSEISelDAGToDAG.cpp b/llvm/lib/Target/Mips/MipsSEISelDAGToDAG.cpp
index 8ea35f1..72c15e2 100644
--- a/llvm/lib/Target/Mips/MipsSEISelDAGToDAG.cpp
+++ b/llvm/lib/Target/Mips/MipsSEISelDAGToDAG.cpp
@@ -47,7 +47,8 @@
                                                MachineFunction &MF) {
   MachineInstrBuilder MIB(MF, &MI);
   unsigned Mask = MI.getOperand(1).getImm();
-  unsigned Flag = IsDef ? RegState::ImplicitDefine : RegState::Implicit;
+  unsigned Flag =
+      IsDef ? RegState::ImplicitDefine : RegState::Implicit | RegState::Undef;
 
   if (Mask & 1)
     MIB.addReg(Mips::DSPPos, Flag);