// indexed by label
BitSet toDelete = new BitSet(blocks.getMaxLabel());
// For each non-deleted block...
for (int bindex = 0; bindex < szBlocks; bindex++) {
BasicBlock b = blocks.get(bindex);
if (toDelete.get(b.getLabel())) {
// doomed block
continue;
}
IntList preds = ropMethod.labelToPredecessors(b.getLabel());
// ...look at all of it's predecessors that have only one succ...
int szPreds = preds.size();
for (int i = 0; i < szPreds; i++) {
int iLabel = preds.get(i);
BasicBlock iBlock = blocks.labelToBlock(iLabel);
if (toDelete.get(iLabel)
|| iBlock.getSuccessors().size() > 1) {
continue;
}
IntList toCombine = new IntList();
// ...and see if they can be combined with any other preds...
for (int j = i + 1; j < szPreds; j++) {
int jLabel = preds.get(j);
BasicBlock jBlock = blocks.labelToBlock(jLabel);
if (jBlock.getSuccessors().size() == 1
&& compareInsns(iBlock, jBlock)) {
toCombine.add(jLabel);
toDelete.set(jLabel);
}