private void combineBlocks(int alphaLabel, IntList betaLabels) {
    int szBetas = betaLabels.size();

    for (int i = 0; i < szBetas; i++) {
      int betaLabel = betaLabels.get(i);
      BasicBlock bb = blocks.labelToBlock(betaLabel);
      IntList preds = ropMethod.labelToPredecessors(bb.getLabel());
      int szPreds = preds.size();

      for (int j = 0; j < szPreds; j++) {
        BasicBlock predBlock = newBlocks.labelToBlock(preds.get(j));
        replaceSucc(predBlock, betaLabel, alphaLabel);
      }
    }
  }
Combines blocks proven identical into one alpha block, re-writing all of the successor links
that point to the beta blocks to point to the alpha block instead.

@param alphaLabel block that will replace all the beta block
@param betaLabels label list of blocks to combine
android/android_framework/dex-maker/src/main/java/com/android/dx/ssa/back/IdenticalBlockCombiner.java