public static void checkRedundantProxy(ProxyNode vpn) {
if (vpn.isDeleted()) {
return;
}
BeginNode proxyPoint = vpn.proxyPoint();
if (proxyPoint instanceof LoopExitNode) {
LoopExitNode exit = (LoopExitNode) proxyPoint;
LoopBeginNode loopBegin = exit.loopBegin();
Node vpnValue = vpn.value();
for (ValueNode v : loopBegin.stateAfter().values()) {
ValueNode v2 = v;
if (loopBegin.isPhiAtMerge(v2)) {
v2 = ((PhiNode) v2).valueAt(loopBegin.forwardEnd());
}
if (vpnValue == v2) {
Collection<PhiNode> phiUsages = vpn.usages().filter(PhiNode.class).snapshot();
Collection<ProxyNode> proxyUsages = vpn.usages().filter(ProxyNode.class).snapshot();
vpn.graph().replaceFloating(vpn, vpnValue);
for (PhiNode phi : phiUsages) {
checkRedundantPhi(phi);
}
for (ProxyNode proxy : proxyUsages) {
checkRedundantProxy(proxy);
}
return;
}
}
}
}
public static void normalizeLoopBegin(LoopBeginNode begin) {
// Delete unnecessary loop phi functions, i.e., phi functions where all inputs are either
// the same or the phi itself.
for (PhiNode phi : begin.phis().snapshot()) {
GraphUtil.checkRedundantPhi(phi);
}
for (LoopExitNode exit : begin.loopExits()) {
for (ProxyNode vpn : exit.proxies().snapshot()) {
GraphUtil.checkRedundantProxy(vpn);
}
}
}
private static void killEnd(AbstractEndNode end, SimplifierTool tool) {
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
if (tool != null) {
merge.phis().forEach(phi -> tool.addToWorkList(phi.usages()));
}
graph.reduceDegenerateLoopBegin((LoopBeginNode) merge);
} else if (merge.phiPredecessorCount() == 1) {
// not a merge anymore
if (tool != null) {
merge.phis().forEach(phi -> tool.addToWorkList(phi.usages()));
}
graph.reduceTrivialMerge(merge);
}
}
}