Subzero: Fix compiler warnings.

src/IceTargetLoweringMIPS32.cpp

Index: src/IceTargetLoweringMIPS32.cpp
diff --git a/src/IceTargetLoweringMIPS32.cpp b/src/IceTargetLoweringMIPS32.cpp
index 69080e7d2ddfbf3f233efceadc54c43d084f92a6..99c32cc19c85fb194063fd3bded43a75fe3eb6c6 100644
--- a/src/IceTargetLoweringMIPS32.cpp
+++ b/src/IceTargetLoweringMIPS32.cpp
@@ -4062,9 +4062,6 @@ void TargetMIPS32::lowerIntrinsicCall(const InstIntrinsicCall *Instr) {
   Variable *Dest = Instr->getDest();
   Type DestTy = (Dest == nullptr) ? IceType_void : Dest->getType();
   switch (Instr->getIntrinsicInfo().ID) {
-  default:
-    llvm::report_fatal_error("Unexpected intrinsic");
-    return;
   case Intrinsics::AtomicCmpxchg: {
     UnimplementedLoweringError(this, Instr);
     return;
@@ -4363,8 +4360,8 @@ void TargetMIPS32::lowerIntrinsicCall(const InstIntrinsicCall *Instr) {
     UnimplementedLoweringError(this, Instr); // Not required for PNaCl
     return;
   }
-  case Intrinsics::UnknownIntrinsic:
-    Func->setError("Should not be lowering UnknownIntrinsic");
+  default: // UnknownIntrinsic
+    Func->setError("Unexpected intrinsic");
     return;
   }
   return;