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[GR-69574] Hoist type check guards out of Vector API loops
PullRequest: graal/22352
2 parents 27b9be5 + aa9073d commit f90caa7

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‎compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/vector/replacements/vectorapi/VectorAPIExpansionPhase.java‎

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@@ -47,19 +47,24 @@
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import jdk.graal.compiler.graph.NodeUnionFind;
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import jdk.graal.compiler.nodes.AbstractBeginNode;
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import jdk.graal.compiler.nodes.ConstantNode;
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import jdk.graal.compiler.nodes.FixedGuardNode;
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import jdk.graal.compiler.nodes.FixedNode;
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import jdk.graal.compiler.nodes.FixedWithNextNode;
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import jdk.graal.compiler.nodes.FrameState;
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import jdk.graal.compiler.nodes.GraphState;
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import jdk.graal.compiler.nodes.Invoke;
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import jdk.graal.compiler.nodes.LogicConstantNode;
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import jdk.graal.compiler.nodes.LogicNode;
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import jdk.graal.compiler.nodes.NodeView;
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import jdk.graal.compiler.nodes.PiNode;
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import jdk.graal.compiler.nodes.ReturnNode;
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import jdk.graal.compiler.nodes.StructuredGraph;
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import jdk.graal.compiler.nodes.ValueNode;
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import jdk.graal.compiler.nodes.ValuePhiNode;
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import jdk.graal.compiler.nodes.ValueProxyNode;
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import jdk.graal.compiler.nodes.calc.MinMaxNode;
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import jdk.graal.compiler.nodes.extended.FixedValueAnchorNode;
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import jdk.graal.compiler.nodes.java.InstanceOfNode;
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import jdk.graal.compiler.nodes.java.MethodCallTargetNode;
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import jdk.graal.compiler.nodes.spi.CoreProviders;
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import jdk.graal.compiler.nodes.spi.SimplifierTool;
@@ -71,13 +76,17 @@
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import jdk.graal.compiler.phases.common.PostRunCanonicalizationPhase;
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import jdk.graal.compiler.phases.tiers.HighTierContext;
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import jdk.graal.compiler.replacements.nodes.MacroWithExceptionNode;
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import jdk.graal.compiler.serviceprovider.SpeculationReasonGroup;
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import jdk.graal.compiler.vector.architecture.VectorArchitecture;
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import jdk.graal.compiler.vector.architecture.VectorLoweringProvider;
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import jdk.graal.compiler.vector.nodes.simd.SimdStamp;
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import jdk.graal.compiler.vector.replacements.vectorapi.nodes.VectorAPIMacroNode;
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import jdk.graal.compiler.vector.replacements.vectorapi.nodes.VectorAPISinkNode;
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import jdk.vm.ci.meta.DeoptimizationReason;
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import jdk.vm.ci.meta.JavaKind;
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import jdk.vm.ci.meta.ResolvedJavaMethod;
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import jdk.vm.ci.meta.ResolvedJavaType;
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import jdk.vm.ci.meta.SpeculationLog;
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/**
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* Expands {@link VectorAPIMacroNode}s to SIMD operations if they are supported by the target
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*/
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public class VectorAPIExpansionPhase extends PostRunCanonicalizationPhase<HighTierContext> {
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private static final SpeculationReasonGroup FIXED_GUARD_HOISTING_SPECULATIONS = new SpeculationReasonGroup("VectorAPIFixedGuardHoisting", ResolvedJavaMethod.class, int.class,
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DeoptimizationReason.class);
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public VectorAPIExpansionPhase(CanonicalizerPhase canonicalizer) {
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super(canonicalizer.copyWithCustomSimplification(new VectorAPIExpansionPhase.VectorAPISimplification()));
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}
@@ -258,6 +270,10 @@ protected void run(StructuredGraph graph, HighTierContext context) {
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return;
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}
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if (graph.getSpeculationLog() != null) {
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speculativelyHoistGuardsThroughPhis(graph, context);
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}
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/*
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* Canonicalize first. Needed for computing SIMD stamps, since we delay their computation to
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* compile time. We can't generally compute SIMD stamps at the time we build the macro nodes
@@ -1000,6 +1016,99 @@ private static void replaceComponentNodes(StructuredGraph graph, HighTierContext
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graph.getDebug().dump(DebugContext.DETAILED_LEVEL, graph, "after adding duplicates for %s", component);
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}
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/*
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* A limit on the width of phis that we are willing to hoist through. The exact value doesn't
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* matter, but as hoisting guards through phis duplicates code, we want some limit to avoid
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* explosive surprises.
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*/
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private static final int MAX_PHI_PREDECESSORS = 4;
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/**
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* Try to improve a graph shape involving loop phis that don't have precise Vector API type
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* stamps. Given code like this:
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*
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* <pre>
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* Object init = [some generic Object value];
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* Object phi = init;
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* loop {
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* Byte128Vector v = (Byte128Vector) phi;
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* Byte128Vector w = v.add(1);
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* phi = w;
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* }
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* </pre>
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*
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* This method will hoist the cast through the phi, placing the guards in all phi predecessors
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* that don't have a precise stamp yet (i.e., in this case, at the loop entry):
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*
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* <pre>
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* Object init = [some generic Object value];
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* Byte128Vector castInit = (Byte128Vector) init; // hoisted type check guard
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* Byte128Vector phi = castInit;
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* loop {
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* phi = phi.add(1);
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* }
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* </pre>
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*
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* In the original code, we have a type check on every loop iteration, plus we would have to
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* insert unboxing/boxing code around the SIMD add operation. In the modified code, we only have
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* one type check and one unboxing before the loop, and the SIMD computation in the loop can be
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* fully unboxed. Reasonably written code should not contain such patterns, but Truffle OSR
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* compilations have such code shapes because OSR locals have generic object stamps.
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* <p>
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*
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* The hoisting of the type check is guarded by a speculation, so we do not repeat this
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* transformation if we ever see the hoisted guard fail.
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*/
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private void speculativelyHoistGuardsThroughPhis(StructuredGraph graph, HighTierContext context) {
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for (VectorAPIMacroNode macro : graph.getNodes(VectorAPIMacroNode.TYPE)) {
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for (ValueNode vectorInput : macro.vectorInputs()) {
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if (vectorInput instanceof PiNode pi && pi.getGuard() instanceof FixedGuardNode guard && guard.canFloat()) {
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if (guard.getCondition() instanceof InstanceOfNode instanceOf &&
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!guard.isNegated() && // if (!(x instanceof T)) { deopt; }
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instanceOf.getValue() == pi.getOriginalNode() &&
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instanceOf.getCheckedStamp().nonNull() &&
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instanceOf.getCheckedStamp().equals(pi.piStamp()) &&
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instanceOf.getValue() instanceof ValuePhiNode phi &&
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phi.valueCount() <= MAX_PHI_PREDECESSORS &&
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phi.isLoopPhi() &&
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VectorAPIBoxingUtils.asUnboxableVectorType(pi, context) != null) {
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SpeculationLog.SpeculationReason speculationReason = FIXED_GUARD_HOISTING_SPECULATIONS.createSpeculationReason(phi.merge().stateAfter().getMethod(),
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phi.merge().stateAfter().bci, guard.getReason());
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if (graph.getSpeculationLog().maySpeculate(speculationReason)) {
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SpeculationLog.Speculation hoistingSpeculation = graph.getSpeculationLog().speculate(speculationReason);
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for (int i = 0; i < phi.valueCount(); i++) {
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LogicNode newCondition = InstanceOfNode.create(instanceOf.type(), phi.valueAt(i));
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if (newCondition instanceof LogicConstantNode logicConstant && logicConstant.getValue() == !guard.isNegated()) {
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/*
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* This phi input already has a precise stamp that doesn't need
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* to be improved.
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*/
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continue;
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}
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newCondition = graph.addOrUnique(newCondition);
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FixedGuardNode newGuard = graph.add(new FixedGuardNode(newCondition, guard.getReason(), guard.getAction(), hoistingSpeculation, guard.isNegated(),
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guard.getNoDeoptSuccessorPosition()));
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graph.addBeforeFixed(phi.merge().phiPredecessorAt(i), newGuard);
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ValueNode newPi = graph.addOrUnique(PiNode.create(phi.valueAt(i), pi.piStamp(), newGuard));
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if (newPi != phi.valueAt(i)) {
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phi.setValueAt(i, newPi);
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}
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}
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/*
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* Improve the phi and canonicalize its usages right away. The original
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* guard and its pi will fold away, and other macros using the same pi
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* will now see the phi with its precise stamp. This way, we don't
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* repeat the same work for other usages of the pi.
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*/
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phi.inferStamp();
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canonicalizer.applyIncremental(graph, context, phi.usages());
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}
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}
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}
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}
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}
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}
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public static class VectorAPISimplification implements CanonicalizerPhase.CustomSimplification {
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@Override

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