Tweak position of startTimer

Author: jayfoad

llvm/utils/TableGen/Common/CodeGenRegisters.cpp

@@ -2449,12 +2449,12 @@ void CodeGenRegBank::computeInferredRegisterClasses() {
   // and assigned EnumValues yet.  That means getSubClasses(),
   // getSuperClasses(), and hasSubClass() functions are defunct.
 
+  Records.getTimer().startTimer("Compute inferred register classes");
+
   // Use one-before-the-end so it doesn't move forward when new elements are
   // added.
   auto FirstNewRC = std::prev(RegClasses.end());
 
-  Records.getTimer().startTimer("Compute inferred register classes");
-
   // Visit all register classes, including the ones being added by the loop.
   // Watch out for iterator invalidation here.
   for (auto I = RegClasses.begin(), E = RegClasses.end(); I != E; ++I) {