Subzero: Fix compiler warnings.

src/IceTargetLoweringX86BaseImpl.h

Index: src/IceTargetLoweringX86BaseImpl.h
diff --git a/src/IceTargetLoweringX86BaseImpl.h b/src/IceTargetLoweringX86BaseImpl.h
index 87bbfde8bb55a3f93996abb00fa210df187cf707..52a5d07cb8a4221f1eb752b6898b510e80cae7d8 100644
--- a/src/IceTargetLoweringX86BaseImpl.h
+++ b/src/IceTargetLoweringX86BaseImpl.h
@@ -4004,9 +4004,6 @@ template <typename TraitsType>
 void TargetX86Base<TraitsType>::lowerIntrinsicCall(
     const InstIntrinsicCall *Instr) {
   switch (Intrinsics::IntrinsicID ID = Instr->getIntrinsicInfo().ID) {
-  default:
-    llvm::report_fatal_error("Unexpected intrinsic");
-    return;
   case Intrinsics::AtomicCmpxchg: {
     if (!Intrinsics::isMemoryOrderValid(
             ID, getConstantMemoryOrder(Instr->getArg(3)),
@@ -4417,8 +4414,8 @@ void TargetX86Base<TraitsType>::lowerIntrinsicCall(
     }
     return;
   }
-  case Intrinsics::UnknownIntrinsic:
-    Func->setError("Should not be lowering UnknownIntrinsic");
+  default: // UnknownIntrinsic
+    Func->setError("Unexpected intrinsic");
     return;
   }
   return;
@@ -6090,7 +6087,6 @@ void TargetX86Base<TraitsType>::lowerShuffleVector(
     if (Instr->indexesAre(0, 8, 1, 9, 2, 10, 3, 11)) {
       auto *T = makeReg(DestTy);
       auto *Src0RM = legalize(Src0, Legal_Reg | Legal_Mem);
-      auto *Src1RM = legalize(Src1, Legal_Reg | Legal_Mem);
       _movp(T, Src0RM);
       _punpckl(T, Src0RM);
       _movp(Dest, T);