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 void reduceTrivialMerge(AbstractMergeNode merge) {
assert merge.forwardEndCount() == 1;
assert !(merge instanceof LoopBeginNode) || ((LoopBeginNode) merge).loopEnds().isEmpty();
for (PhiNode phi : merge.phis().snapshot()) {
assert phi.valueCount() == 1;
ValueNode singleValue = phi.valueAt(0);
phi.replaceAtUsagesAndDelete(singleValue);
}
// remove loop exits
if (merge instanceof LoopBeginNode) {
((LoopBeginNode) merge).removeExits();
}
AbstractEndNode singleEnd = merge.forwardEndAt(0);
FixedNode sux = merge.next();
FrameState stateAfter = merge.stateAfter();
// evacuateGuards
merge.prepareDelete((FixedNode) singleEnd.predecessor());
merge.safeDelete();
if (stateAfter != null && stateAfter.isAlive() && stateAfter.hasNoUsages()) {
GraphUtil.killWithUnusedFloatingInputs(stateAfter);
}
if (sux == null) {
singleEnd.replaceAtPredecessor(null);
singleEnd.safeDelete();
} else {
singleEnd.replaceAndDelete(sux);
}
}
/**
* Unlinks a node from all its control flow neighbors and then removes it from its graph. The node
* must have no {@linkplain Node#usages() usages}.
*
* @param node the node to be unlinked and removed
*/
public void removeFixed(FixedWithNextNode node) {
assert node != null;
if (node instanceof AbstractBeginNode) {
((AbstractBeginNode) node).prepareDelete();
}
assert node.hasNoUsages() : node + " " + node.usages().count() + ", " + node.usages().first();
GraphUtil.unlinkFixedNode(node);
node.safeDelete();
}
public final void clearAllStateAfter() {
for (Node node : getNodes()) {
if (node instanceof StateSplit) {
FrameState stateAfter = ((StateSplit) node).stateAfter();
if (stateAfter != null) {
((StateSplit) node).setStateAfter(null);
GraphUtil.killWithUnusedFloatingInputs(stateAfter);
}
}
}
}
public void removeSplitPropagate(
ControlSplitNode node, AbstractBeginNode survivingSuccessor, SimplifierTool tool) {
assert node != null;
assert node.hasNoUsages();
assert survivingSuccessor != null;
List<Node> snapshot = node.successors().snapshot();
node.clearSuccessors();
node.replaceAtPredecessor(survivingSuccessor);
node.safeDelete();
for (Node successor : snapshot) {
if (successor != null && successor.isAlive()) {
if (successor != survivingSuccessor) {
GraphUtil.killCFG(successor, tool);
}
}
}
}
/**
* This method performs two kinds of cleanup:
*
* <ol>
* <li>marking as unreachable certain code-paths, as described in {@link
* com.oracle.graal.phases.common.cfs.BaseReduction.PostponedDeopt}
* <li>Removing nodes not in use that were added during this phase, as described next.
* </ol>
*
* <p>Methods like {@link
* com.oracle.graal.phases.common.cfs.FlowUtil#replaceInPlace(com.oracle.graal.graph.Node,
* com.oracle.graal.graph.Node, com.oracle.graal.graph.Node)} may result in old inputs becoming
* disconnected from the graph. It's not advisable to {@link
* com.oracle.graal.nodes.util.GraphUtil#tryKillUnused(com.oracle.graal.graph.Node)} at that
* moment, because one of the inputs that might get killed is one of {@link #nullConstant}, {@link
* #falseConstant}, or {@link #trueConstant}; which thus could get killed too early, before
* another invocation of {@link
* com.oracle.graal.phases.common.cfs.EquationalReasoner#deverbosify(com.oracle.graal.graph.Node)}
* needs them. To recap, {@link
* com.oracle.graal.nodes.util.GraphUtil#tryKillUnused(com.oracle.graal.graph.Node)} also
* recursively visits the inputs of the its argument.
*
* <p>This method goes over all of the nodes that deverbosification might have added, which are
* either:
*
* <ul>
* <li>{@link com.oracle.graal.nodes.calc.FloatingNode}, added by {@link
* com.oracle.graal.phases.common.cfs.EquationalReasoner#deverbosifyFloatingNode(com.oracle.graal.nodes.calc.FloatingNode)}
* ; or
* <li>{@link com.oracle.graal.nodes.java.MethodCallTargetNode}, added by {@link
* #deverbosifyInputsCopyOnWrite(com.oracle.graal.nodes.java.MethodCallTargetNode)}
* </ul>
*
* Checking if they aren't in use, proceeding to remove them in that case.
*/
@Override
public void finished() {
if (!postponedDeopts.isEmpty()) {
for (PostponedDeopt postponed : postponedDeopts) {
postponed.doRewrite(falseConstant);
}
new DeadCodeEliminationPhase(Optional).apply(graph);
}
for (MethodCallTargetNode mcn : graph.getNodes().filter(MethodCallTargetNode.class)) {
if (mcn.isAlive() && FlowUtil.lacksUsages(mcn)) {
mcn.safeDelete();
}
}
for (Node n : graph.getNodes().filter(FloatingNode.class)) {
GraphUtil.tryKillUnused(n);
}
assert !isAliveWithoutUsages(trueConstant);
assert !isAliveWithoutUsages(falseConstant);
assert !isAliveWithoutUsages(nullConstant);
super.finished();
}
@Test
public void testValueProxyInputs() {
StructuredGraph graph = parseEager("testValueProxyInputsSnippet", AllowAssumptions.YES);
for (FrameState fs : graph.getNodes().filter(FrameState.class).snapshot()) {
fs.replaceAtUsages(null);
GraphUtil.killWithUnusedFloatingInputs(fs);
}
SchedulePhase schedulePhase = new SchedulePhase(SchedulingStrategy.LATEST);
schedulePhase.apply(graph);
ScheduleResult schedule = graph.getLastSchedule();
NodeMap<Block> nodeToBlock = schedule.getCFG().getNodeToBlock();
assertTrue(graph.getNodes().filter(LoopExitNode.class).count() == 1);
LoopExitNode loopExit = graph.getNodes().filter(LoopExitNode.class).first();
List<Node> list = schedule.nodesFor(nodeToBlock.get(loopExit));
for (BinaryArithmeticNode<?> node : graph.getNodes().filter(BinaryArithmeticNode.class)) {
if (!(node instanceof AddNode)) {
assertTrue(node.toString(), nodeToBlock.get(node) == nodeToBlock.get(loopExit));
assertTrue(
list.indexOf(node) + " < " + list.indexOf(loopExit) + ", " + node + ", " + loopExit,
list.indexOf(node) < list.indexOf(loopExit));
}
}
}
private static AbstractBeginNode findBeginNode(FixedNode startNode) {
return GraphUtil.predecessorIterable(startNode).filter(AbstractBeginNode.class).first();
}
/**
* This phase will find branches which always end with a {@link DeoptimizeNode} and replace their
* {@link ControlSplitNode ControlSplitNodes} with {@link FixedGuardNode FixedGuardNodes}.
*
* <p>This is useful because {@link FixedGuardNode FixedGuardNodes} will be lowered to {@link
* GuardNode GuardNodes} which can later be optimized more aggressively than control-flow
* constructs.
*
* <p>This is currently only done for branches that start from a {@link IfNode}. If it encounters a
* branch starting at an other kind of {@link ControlSplitNode}, it will only bring the {@link
* DeoptimizeNode} as close to the {@link ControlSplitNode} as possible.
*/
public class ConvertDeoptimizeToGuardPhase extends BasePhase<PhaseContext> {
private SimplifierTool simplifierTool = GraphUtil.getDefaultSimplifier(null, null, false);
private static AbstractBeginNode findBeginNode(FixedNode startNode) {
return GraphUtil.predecessorIterable(startNode).filter(AbstractBeginNode.class).first();
}
@Override
protected void run(final StructuredGraph graph, PhaseContext context) {
assert graph.hasValueProxies() : "ConvertDeoptimizeToGuardPhase always creates proxies";
if (graph.getNodes(DeoptimizeNode.TYPE).isEmpty()) {
return;
}
for (DeoptimizeNode d : graph.getNodes(DeoptimizeNode.TYPE)) {
assert d.isAlive();
visitDeoptBegin(
AbstractBeginNode.prevBegin(d), d.action(), d.reason(), d.getSpeculation(), graph);
}
if (context != null) {
for (FixedGuardNode fixedGuard : graph.getNodes(FixedGuardNode.TYPE)) {
trySplitFixedGuard(fixedGuard, context);
}
}
new DeadCodeEliminationPhase(Optional).apply(graph);
}
private void trySplitFixedGuard(FixedGuardNode fixedGuard, PhaseContext context) {
LogicNode condition = fixedGuard.condition();
if (condition instanceof CompareNode) {
CompareNode compare = (CompareNode) condition;
ValueNode x = compare.getX();
ValuePhiNode xPhi = (x instanceof ValuePhiNode) ? (ValuePhiNode) x : null;
if (x instanceof ConstantNode || xPhi != null) {
ValueNode y = compare.getY();
ValuePhiNode yPhi = (y instanceof ValuePhiNode) ? (ValuePhiNode) y : null;
if (y instanceof ConstantNode || yPhi != null) {
processFixedGuardAndPhis(fixedGuard, context, compare, x, xPhi, y, yPhi);
}
}
}
}
private void processFixedGuardAndPhis(
FixedGuardNode fixedGuard,
PhaseContext context,
CompareNode compare,
ValueNode x,
ValuePhiNode xPhi,
ValueNode y,
ValuePhiNode yPhi) {
AbstractBeginNode pred = AbstractBeginNode.prevBegin(fixedGuard);
if (pred instanceof AbstractMergeNode) {
AbstractMergeNode merge = (AbstractMergeNode) pred;
if (xPhi != null && xPhi.merge() != merge) {
return;
}
if (yPhi != null && yPhi.merge() != merge) {
return;
}
processFixedGuardAndMerge(fixedGuard, context, compare, x, xPhi, y, yPhi, merge);
}
}
private void processFixedGuardAndMerge(
FixedGuardNode fixedGuard,
PhaseContext context,
CompareNode compare,
ValueNode x,
ValuePhiNode xPhi,
ValueNode y,
ValuePhiNode yPhi,
AbstractMergeNode merge) {
List<EndNode> mergePredecessors = merge.cfgPredecessors().snapshot();
for (int i = 0; i < mergePredecessors.size(); ++i) {
AbstractEndNode mergePredecessor = mergePredecessors.get(i);
if (!mergePredecessor.isAlive()) {
break;
}
Constant xs;
if (xPhi == null) {
xs = x.asConstant();
} else {
xs = xPhi.valueAt(mergePredecessor).asConstant();
}
Constant ys;
if (yPhi == null) {
ys = y.asConstant();
} else {
ys = yPhi.valueAt(mergePredecessor).asConstant();
}
if (xs != null
&& ys != null
&& compare
.condition()
.foldCondition(xs, ys, context.getConstantReflection(), compare.unorderedIsTrue())
== fixedGuard.isNegated()) {
visitDeoptBegin(
AbstractBeginNode.prevBegin(mergePredecessor),
fixedGuard.getAction(),
fixedGuard.getReason(),
fixedGuard.getSpeculation(),
fixedGuard.graph());
}
}
}
private void visitDeoptBegin(
AbstractBeginNode deoptBegin,
DeoptimizationAction deoptAction,
DeoptimizationReason deoptReason,
JavaConstant speculation,
StructuredGraph graph) {
if (deoptBegin.predecessor() instanceof AbstractBeginNode) {
/* Walk up chains of LoopExitNodes to the "real" BeginNode that leads to deoptimization. */
visitDeoptBegin(
(AbstractBeginNode) deoptBegin.predecessor(),
deoptAction,
deoptReason,
speculation,
graph);
return;
}
if (deoptBegin instanceof AbstractMergeNode) {
AbstractMergeNode mergeNode = (AbstractMergeNode) deoptBegin;
Debug.log("Visiting %s", mergeNode);
FixedNode next = mergeNode.next();
while (mergeNode.isAlive()) {
AbstractEndNode end = mergeNode.forwardEnds().first();
AbstractBeginNode newBeginNode = findBeginNode(end);
visitDeoptBegin(newBeginNode, deoptAction, deoptReason, speculation, graph);
}
assert next.isAlive();
AbstractBeginNode newBeginNode = findBeginNode(next);
visitDeoptBegin(newBeginNode, deoptAction, deoptReason, speculation, graph);
return;
} else if (deoptBegin.predecessor() instanceof IfNode) {
IfNode ifNode = (IfNode) deoptBegin.predecessor();
AbstractBeginNode otherBegin = ifNode.trueSuccessor();
LogicNode conditionNode = ifNode.condition();
FixedGuardNode guard =
graph.add(
new FixedGuardNode(
conditionNode,
deoptReason,
deoptAction,
speculation,
deoptBegin == ifNode.trueSuccessor()));
FixedWithNextNode pred = (FixedWithNextNode) ifNode.predecessor();
AbstractBeginNode survivingSuccessor;
if (deoptBegin == ifNode.trueSuccessor()) {
survivingSuccessor = ifNode.falseSuccessor();
} else {
survivingSuccessor = ifNode.trueSuccessor();
}
graph.removeSplitPropagate(ifNode, survivingSuccessor);
Node newGuard = guard;
if (survivingSuccessor instanceof LoopExitNode) {
newGuard = ProxyNode.forGuard(guard, (LoopExitNode) survivingSuccessor, graph);
}
survivingSuccessor.replaceAtUsages(InputType.Guard, newGuard);
Debug.log(
"Converting deopt on %-5s branch of %s to guard for remaining branch %s.",
deoptBegin == ifNode.trueSuccessor() ? "true" : "false", ifNode, otherBegin);
FixedNode next = pred.next();
pred.setNext(guard);
guard.setNext(next);
survivingSuccessor.simplify(simplifierTool);
return;
}
// We could not convert the control split - at least cut off control flow after the split.
FixedWithNextNode deoptPred = deoptBegin;
FixedNode next = deoptPred.next();
if (!(next instanceof DeoptimizeNode)) {
DeoptimizeNode newDeoptNode =
graph.add(new DeoptimizeNode(deoptAction, deoptReason, speculation));
deoptPred.setNext(newDeoptNode);
assert deoptPred == newDeoptNode.predecessor();
GraphUtil.killCFG(next);
}
}
}
private void visitDeoptBegin(
AbstractBeginNode deoptBegin,
DeoptimizationAction deoptAction,
DeoptimizationReason deoptReason,
JavaConstant speculation,
StructuredGraph graph) {
if (deoptBegin.predecessor() instanceof AbstractBeginNode) {
/* Walk up chains of LoopExitNodes to the "real" BeginNode that leads to deoptimization. */
visitDeoptBegin(
(AbstractBeginNode) deoptBegin.predecessor(),
deoptAction,
deoptReason,
speculation,
graph);
return;
}
if (deoptBegin instanceof AbstractMergeNode) {
AbstractMergeNode mergeNode = (AbstractMergeNode) deoptBegin;
Debug.log("Visiting %s", mergeNode);
FixedNode next = mergeNode.next();
while (mergeNode.isAlive()) {
AbstractEndNode end = mergeNode.forwardEnds().first();
AbstractBeginNode newBeginNode = findBeginNode(end);
visitDeoptBegin(newBeginNode, deoptAction, deoptReason, speculation, graph);
}
assert next.isAlive();
AbstractBeginNode newBeginNode = findBeginNode(next);
visitDeoptBegin(newBeginNode, deoptAction, deoptReason, speculation, graph);
return;
} else if (deoptBegin.predecessor() instanceof IfNode) {
IfNode ifNode = (IfNode) deoptBegin.predecessor();
AbstractBeginNode otherBegin = ifNode.trueSuccessor();
LogicNode conditionNode = ifNode.condition();
FixedGuardNode guard =
graph.add(
new FixedGuardNode(
conditionNode,
deoptReason,
deoptAction,
speculation,
deoptBegin == ifNode.trueSuccessor()));
FixedWithNextNode pred = (FixedWithNextNode) ifNode.predecessor();
AbstractBeginNode survivingSuccessor;
if (deoptBegin == ifNode.trueSuccessor()) {
survivingSuccessor = ifNode.falseSuccessor();
} else {
survivingSuccessor = ifNode.trueSuccessor();
}
graph.removeSplitPropagate(ifNode, survivingSuccessor);
Node newGuard = guard;
if (survivingSuccessor instanceof LoopExitNode) {
newGuard = ProxyNode.forGuard(guard, (LoopExitNode) survivingSuccessor, graph);
}
survivingSuccessor.replaceAtUsages(InputType.Guard, newGuard);
Debug.log(
"Converting deopt on %-5s branch of %s to guard for remaining branch %s.",
deoptBegin == ifNode.trueSuccessor() ? "true" : "false", ifNode, otherBegin);
FixedNode next = pred.next();
pred.setNext(guard);
guard.setNext(next);
survivingSuccessor.simplify(simplifierTool);
return;
}
// We could not convert the control split - at least cut off control flow after the split.
FixedWithNextNode deoptPred = deoptBegin;
FixedNode next = deoptPred.next();
if (!(next instanceof DeoptimizeNode)) {
DeoptimizeNode newDeoptNode =
graph.add(new DeoptimizeNode(deoptAction, deoptReason, speculation));
deoptPred.setNext(newDeoptNode);
assert deoptPred == newDeoptNode.predecessor();
GraphUtil.killCFG(next);
}
}
public void replaceFixedWithFloating(FixedWithNextNode node, FloatingNode replacement) {
assert node != null && replacement != null && node.isAlive() && replacement.isAlive()
: "cannot replace " + node + " with " + replacement;
GraphUtil.unlinkFixedNode(node);
node.replaceAtUsagesAndDelete(replacement);
}
public void removeIfUnused(Node node) {
GraphUtil.tryKillUnused(node);
}
public void deleteBranch(Node branch) {
branch.predecessor().replaceFirstSuccessor(branch, null);
GraphUtil.killCFG(branch, this);
}