TableGen/GlobalISel: Don't reconstruct CodeGenRegBank

[arsenm]

Summary

The maps for dealing with the relationships between different register
classes and subregister indexes rely on unique pointers for every
class/index. By constructing a second copy of CodeGenRegBank, two
different pointer values existed for a given subregister depending on
where you were querying.

Use the existing CodeGenRegBank owned by the CodeGenTarget instead of
constructing a second copy. This avoids incorrectly failing map
lookups in a future change.

[dsanders]

LGTM

[arsenm]

3ab7b7f53552a0969bd89db3317eb5a3ddf31d8f

llvm/utils/TableGen/GlobalISelEmitter.cpp

 public:
   explicit GlobalISelEmitter(RecordKeeper &RK);
   void run(raw_ostream &OS);
 
 private:
   const RecordKeeper &RK;
   const CodeGenDAGPatterns CGP;
   const CodeGenTarget &Target;
-  CodeGenRegBank CGRegs;
+  CodeGenRegBank &CGRegs;
 
   /// Keep track of the equivalence between SDNodes and Instruction by mapping
   /// SDNodes to the GINodeEquiv mapping. We need to map to the GINodeEquiv to
   /// check for attributes on the relation such as CheckMMOIsNonAtomic.
   /// This is defined using 'GINodeEquiv' in the target description.
   DenseMap<Record *, Record *> NodeEquivs;
 
   /// Keep track of the equivalence between ComplexPattern's and
if (!Equiv.isValueUnset("IfZeroExtend") && Predicate.isLoad() &&
       return &Target.getInstruction(Equiv.getValueAsDef("IfZeroExtend"));
   }
 
   return &Target.getInstruction(Equiv.getValueAsDef("I"));
 }
 
 GlobalISelEmitter::GlobalISelEmitter(RecordKeeper &RK)
     : RK(RK), CGP(RK), Target(CGP.getTargetInfo()),
-      CGRegs(RK, Target.getHwModes()) {}
+      CGRegs(Target.getRegBank()) {}
 
 //===- Emitter ------------------------------------------------------------===//
 
 Error
 GlobalISelEmitter::importRulePredicates(RuleMatcher &M,
                                         ArrayRef<Predicate> Predicates) {
   for (const Predicate &P : Predicates) {
     if (!P.Def || P.getCondString().empty())