Compute a map from register names to registers, rather than scanning the list of registers every time we want to look up a register by name.

llvm-svn: 163659

llvm/utils/TableGen/CodeGenRegisters.cpp

@@ -993,6 +993,12 @@ CodeGenRegBank::CodeGenRegBank(RecordKeeper &Records) {
   for (unsigned i = 0, e = Registers.size(); i != e; ++i)
     Registers[i]->buildObjectGraph(*this);
 
+  // Compute register name map.
+  for (unsigned i = 0, e = Registers.size(); i != e; ++i)
+    RegistersByName.GetOrCreateValue(
+                       Registers[i]->TheDef->getValueAsString("AsmName"),
+                       Registers[i]);
+
   // Precompute all sub-register maps.
   // This will create Composite entries for all inferred sub-register indices.
   for (unsigned i = 0, e = Registers.size(); i != e; ++i)

llvm/utils/TableGen/CodeGenRegisters.h

@@ -440,6 +440,7 @@ namespace llvm {
 
     // Registers.
     std::vector<CodeGenRegister*> Registers;
+    StringMap<CodeGenRegister*> RegistersByName;
     DenseMap<Record*, CodeGenRegister*> Def2Reg;
     unsigned NumNativeRegUnits;
 
@@ -522,6 +523,9 @@ namespace llvm {
     }
 
     const std::vector<CodeGenRegister*> &getRegisters() { return Registers; }
+    const StringMap<CodeGenRegister*> &getRegistersByName() {
+      return RegistersByName;
+    }
 
     // Find a register from its Record def.
     CodeGenRegister *getReg(Record*);

llvm/utils/TableGen/CodeGenTarget.cpp

@@ -199,12 +199,11 @@ void CodeGenTarget::ReadRegAltNameIndices() const {
 /// getRegisterByName - If there is a register with the specific AsmName,
 /// return it.
 const CodeGenRegister *CodeGenTarget::getRegisterByName(StringRef Name) const {
-  const std::vector<CodeGenRegister*> &Regs = getRegBank().getRegisters();
-  for (unsigned i = 0, e = Regs.size(); i != e; ++i)
-    if (Regs[i]->TheDef->getValueAsString("AsmName") == Name)
-      return Regs[i];
-
-  return 0;
+  const StringMap<CodeGenRegister*> &Regs = getRegBank().getRegistersByName();
+  StringMap<CodeGenRegister*>::const_iterator I = Regs.find(Name);
+  if (I == Regs.end())
+    return 0;
+  return I->second;
 }
 
 std::vector<MVT::SimpleValueType> CodeGenTarget::