/**
* Return the location in the block to split. Use the last spill store point found as the location
* to split. If no spill store is found, use the last instruction that does not cause a violation.
* This method will throw an exception if not split location is found.
*/
private final Instruction findSplitLocation(Hyperblock hb, PredicateBlock block, int chunkSize) {
int cLSID = 0;
int cSize = 0;
Instruction splitLocation = null;
boolean foundSpillPoint = false;
BitVect mov3 = new BitVect();
Stack<Node> wl = new Stack<Node>();
IntMap<Integer> uses = new IntMap<Integer>(37);
IntMap<Vector<Integer>> targets = hb.computeTargets(wl, mov3);
for (Instruction inst = block.getFirstInstruction(); inst != null; inst = inst.getNext()) {
if (inst.isMarker()) {
continue;
}
if (inst.isLoad() || inst.isStore()) {
int id =
(inst.isLoad()
? ((LoadInstruction) inst).getLSQid()
: ((StoreInstruction) inst).getLSQid());
if (id > cLSID) {
cLSID = id;
}
}
cSize += block.estimateNumInstructions(inst);
cSize += block.estimateFanout(inst, targets, uses, mov3);
if ((cLSID >= Trips2Machine.maxLSQEntries) || (cSize >= chunkSize)) {
if (splitLocation == null) {
splitLocation = inst; // Possible when splitting because of spills.
}
assert (splitLocation != block.getLastInstruction())
: "How is the last instruction the split location?";
return splitLocation;
}
if (inst.isSpillStorePoint()) {
splitLocation = inst;
foundSpillPoint = true;
}
if (!foundSpillPoint) {
splitLocation = inst;
}
}
throw new scale.common.InternalError("Could not find a location to split the predicate block.");
}
