public static void checkRedundantProxy(ProxyNode vpn) {
AbstractBeginNode proxyPoint = vpn.proxyPoint();
if (proxyPoint instanceof LoopExitNode) {
LoopExitNode exit = (LoopExitNode) proxyPoint;
LoopBeginNode loopBegin = exit.loopBegin();
ValueNode 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);
}
}
}
public static void checkRedundantPhi(PhiNode phiNode) {
if (phiNode.isDeleted() || phiNode.valueCount() == 1) {
return;
}
ValueNode singleValue = phiNode.singleValue();
if (singleValue != null) {
Collection<PhiNode> phiUsages = phiNode.usages().filter(PhiNode.class).snapshot();
Collection<ProxyNode> proxyUsages = phiNode.usages().filter(ProxyNode.class).snapshot();
phiNode.graph().replaceFloating(phiNode, singleValue);
for (PhiNode phi : phiUsages) {
checkRedundantPhi(phi);
}
for (ProxyNode proxy : proxyUsages) {
checkRedundantProxy(proxy);
}
}
}