/** Test if two canonical regions could be merge in one non canonical region. */
private boolean isNonCanonicalRegion(RPST rpst, Region region1, Region region2) {
if (!region1.getExit().equals(region2.getEntry())) {
return false;
}
if (rpst.getChildCount(region2) == 0) {
return false;
}
// basic blocks of merged region
Set<BasicBlock> basicBlocks = new HashSet<>();
basicBlocks.addAll(rpst.getBasicBlocks(region1));
basicBlocks.addAll(rpst.getBasicBlocks(region2));
basicBlocks.add(region2.getExit());
if (!basicBlocks.containsAll(cfg.getSuccessorsOf(region1.getExit()))) {
return false;
}
if (!basicBlocks.containsAll(cfg.getPredecessorsOf(region1.getExit()))) {
return false;
}
return true;
}
private void findNonCanonicalRegions(RPST rpst, Region region) {
Set<Region> childrenBefore = new HashSet<>(rpst.getChildren(region));
if (rpst.getChildCount(region) > 1) {
boolean found = true;
while (found) {
found = false;
// children ordered by dominance
List<Region> children = new ArrayList<>(rpst.getChildren(region));
Collections.sort(
children,
new Comparator<Region>() {
@Override
public int compare(Region region1, Region region2) {
return getDomInfo().dominates(region1.getEntry(), region2.getEntry()) ? 1 : -1;
}
});
for (Region child1 : children) {
for (Region child2 : children) {
if (!child1.equals(child2)) {
if (isNonCanonicalRegion(rpst, child1, child2)) {
Region newRegion =
new RegionImpl(child1.getEntry(), child2.getExit(), ParentType.UNDEFINED);
LOGGER.debug("New non canonical region {}", newRegion);
rpst.addRegion(newRegion, region);
rpst.setNewParent(child1, newRegion);
rpst.setNewParent(child2, newRegion);
found = true;
break;
}
}
}
if (found) {
break;
}
}
}
}
for (Region child : childrenBefore) {
findNonCanonicalRegions(rpst, child);
}
}
