Subzero: Expand the liveness consistency check.

src/IceTargetLoweringMIPS32.cpp

Index: src/IceTargetLoweringMIPS32.cpp
diff --git a/src/IceTargetLoweringMIPS32.cpp b/src/IceTargetLoweringMIPS32.cpp
index 5e87fa7c51b855cab13ff0ec5679bb8f3cb58557..a59f486c3aaec1cdbb510d4a083a9eda0690cb9a 100644
--- a/src/IceTargetLoweringMIPS32.cpp
+++ b/src/IceTargetLoweringMIPS32.cpp
@@ -246,7 +246,7 @@ Variable *TargetMIPS32::getPhysicalRegister(SizeT RegNum, Type Ty) {
     PhysicalRegisters[Ty][RegNum] = Reg;
     // Specially mark SP as an "argument" so that it is considered
     // live upon function entry.
-    if (RegNum == RegMIPS32::Reg_SP) {
+    if (RegNum == RegMIPS32::Reg_SP || RegNum == RegMIPS32::Reg_RA) {
       Func->addImplicitArg(Reg);
       Reg->setIgnoreLiveness();
     }