Subzero: Refactor x86 register definitions to use the alias mechanism.

src/IceTargetLowering.cpp

Index: src/IceTargetLowering.cpp
diff --git a/src/IceTargetLowering.cpp b/src/IceTargetLowering.cpp
index 585f3722fd3a508df2ba4958d0d19b8d8572718f..4902a3d64a8637a75decad7d1012ee626cd608a9 100644
--- a/src/IceTargetLowering.cpp
+++ b/src/IceTargetLowering.cpp
@@ -112,7 +112,7 @@ std::unique_ptr<Assembler> TargetLowering::createAssembler(TargetArch Target,
                                                            Cfg *Func) {
 #define SUBZERO_TARGET(X)                                                      \
   if (Target == Target_##X)                                                    \
-    return std::unique_ptr<Assembler>(new X::Assembler##X(Func->getContext()));
+    return std::unique_ptr<Assembler>(new X::Assembler##X());
 #include "llvm/Config/SZTargets.def"
 
   Func->setError("Unsupported target assembler");
@@ -460,7 +460,7 @@ void TargetLowering::assignVarStackSlots(VarList &SortedSpilledVariables,
 
 InstCall *TargetLowering::makeHelperCall(const IceString &Name, Variable *Dest,
                                          SizeT MaxSrcs) {
-  const bool HasTailCall = false;
+  constexpr bool HasTailCall = false;
   Constant *CallTarget = Ctx->getConstantExternSym(Name);
   InstCall *Call =
       InstCall::create(Func, MaxSrcs, Dest, CallTarget, HasTailCall);