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);
}
}
}
/**
* The {@link com.oracle.graal.nodes.AbstractEndNode} at the end of the current code path
* contributes values to {@link com.oracle.graal.nodes.PhiNode}s. Now is a good time to {@link
* EquationalReasoner#deverbosify(com.oracle.graal.graph.Node) EquationalReasoner#deverbosify}
* those values.
*
* <p>Precondition: inputs haven't been deverbosified yet.
*/
private void visitAbstractEndNode(AbstractEndNode endNode) {
MergeNode merge = endNode.merge();
for (PhiNode phi : merge.phis()) {
if (phi instanceof ValuePhiNode && phi.getKind() == Kind.Object) {
assert phi.verify();
int index = merge.phiPredecessorIndex(endNode);
ValueNode original = phi.valueAt(index);
ValueNode reduced = (ValueNode) reasoner.deverbosify(original);
if (reduced != original) {
phi.setValueAt(index, reduced);
// `original` if unused will be removed in finished()
}
}
}
}