public final void setResultLocal(LocalItem local) {
    LocalItem oldItem = result.getLocalItem();

    if (local != oldItem && (local == null || !local.equals(result.getLocalItem()))) {
      result = RegisterSpec.makeLocalOptional(result.getReg(), result.getType(), local);
    }
  }
Sets the local association for the result of this insn. This is sometimes updated during the
SsaRenamer process.

@param local {@code null-ok;} new debug/local variable info
android/android_framework/dex-maker/src/main/java/com/android/dx/ssa/SsaInsn.java