private static void killEnd(AbstractEndNode end) {
MergeNode merge = end.merge();
if (merge != null) {
merge.removeEnd(end);
StructuredGraph graph = end.graph();
if (merge instanceof LoopBeginNode && merge.forwardEndCount() == 0) { // dead loop
for (PhiNode phi : merge.phis().snapshot()) {
propagateKill(phi);
}
LoopBeginNode begin = (LoopBeginNode) merge;
// disconnect and delete loop ends & loop exits
for (LoopEndNode loopend : begin.loopEnds().snapshot()) {
loopend.predecessor().replaceFirstSuccessor(loopend, null);
loopend.safeDelete();
}
begin.removeExits();
FixedNode loopBody = begin.next();
if (loopBody != null) { // for small infinite loops, the body may be killed while
// killing the loop ends
killCFG(loopBody);
}
begin.safeDelete();
} else if (merge instanceof LoopBeginNode
&& ((LoopBeginNode) merge).loopEnds().isEmpty()) { // not
// a
// loop
// anymore
graph.reduceDegenerateLoopBegin((LoopBeginNode) merge);
} else if (merge.phiPredecessorCount() == 1) { // not a merge anymore
graph.reduceTrivialMerge(merge);
}
}
}
public void detectedCountedLoops() {
for (LoopEx loop : loops()) {
InductionVariables ivs = new InductionVariables(loop);
LoopBeginNode loopBegin = loop.loopBegin();
FixedNode next = loopBegin.next();
while (next instanceof FixedGuardNode || next instanceof ValueAnchorNode) {
next = ((FixedWithNextNode) next).next();
}
if (next instanceof IfNode) {
IfNode ifNode = (IfNode) next;
boolean negated = false;
if (!loopBegin.isLoopExit(ifNode.falseSuccessor())) {
if (!loopBegin.isLoopExit(ifNode.trueSuccessor())) {
continue;
}
negated = true;
}
LogicNode ifTest = ifNode.condition();
if (!(ifTest instanceof IntegerLessThanNode)) {
if (ifTest instanceof IntegerBelowThanNode) {
Debug.log("Ignored potential Counted loop at %s with |<|", loopBegin);
}
continue;
}
IntegerLessThanNode lessThan = (IntegerLessThanNode) ifTest;
Condition condition = null;
InductionVariable iv = null;
ValueNode limit = null;
if (loop.isOutsideLoop(lessThan.x())) {
iv = ivs.get(lessThan.y());
if (iv != null) {
condition = lessThan.condition().mirror();
limit = lessThan.x();
}
} else if (loop.isOutsideLoop(lessThan.y())) {
iv = ivs.get(lessThan.x());
if (iv != null) {
condition = lessThan.condition();
limit = lessThan.y();
}
}
if (condition == null) {
continue;
}
if (negated) {
condition = condition.negate();
}
boolean oneOff = false;
switch (condition) {
case LE:
oneOff = true; // fall through
case LT:
if (iv.direction() != Direction.Up) {
continue;
}
break;
case GE:
oneOff = true; // fall through
case GT:
if (iv.direction() != Direction.Down) {
continue;
}
break;
default:
throw GraalInternalError.shouldNotReachHere();
}
loop.setCounted(
new CountedLoopInfo(
loop,
iv,
limit,
oneOff,
negated ? ifNode.falseSuccessor() : ifNode.trueSuccessor()));
}
}
}
