Store CodeGenRegisters as pointers so they won't be reallocated.

Reuse the CodeGenRegBank DenseMap in a few places that would build their
own or use linear search.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133333 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/DAGISelMatcherGen.cpp b/utils/TableGen/DAGISelMatcherGen.cpp
index a8736fa..54553a8 100644
--- a/utils/TableGen/DAGISelMatcherGen.cpp
+++ b/utils/TableGen/DAGISelMatcherGen.cpp
@@ -93,10 +93,6 @@
     /// CurPredicate - As we emit matcher nodes, this points to the latest check
     /// which should have future checks stuck into its Next position.
     Matcher *CurPredicate;
-
-    /// RegisterDefMap - A map of register record definitions to the
-    /// corresponding target CodeGenRegister entry.
-    DenseMap<const Record *, const CodeGenRegister *> RegisterDefMap;
   public:
     MatcherGen(const PatternToMatch &pattern, const CodeGenDAGPatterns &cgp);
 
@@ -165,12 +161,6 @@
 
   // If there are types that are manifestly known, infer them.
   InferPossibleTypes();
-
-  // Populate the map from records to CodeGenRegister entries.
-  const CodeGenTarget &CGT = CGP.getTargetInfo();
-  const std::vector<CodeGenRegister> &Registers = CGT.getRegisters();
-  for (unsigned i = 0, e = Registers.size(); i != e; ++i)
-    RegisterDefMap[Registers[i].TheDef] = &Registers[i];
 }
 
 /// InferPossibleTypes - As we emit the pattern, we end up generating type
@@ -590,8 +580,9 @@
   // If this is an explicit register reference, handle it.
   if (DefInit *DI = dynamic_cast<DefInit*>(N->getLeafValue())) {
     if (DI->getDef()->isSubClassOf("Register")) {
-      AddMatcher(new EmitRegisterMatcher(RegisterDefMap[DI->getDef()],
-                                         N->getType(0)));
+      const CodeGenRegister *Reg =
+        CGP.getTargetInfo().getRegBank().getReg(DI->getDef());
+      AddMatcher(new EmitRegisterMatcher(Reg, N->getType(0)));
       ResultOps.push_back(NextRecordedOperandNo++);
       return;
     }