Examples with RandomSeedNode org.graalvm.compiler.hotspot.nodes.profiling.RandomSeedNode used on opensource projects

Example 1 with RandomSeedNode

use of org.graalvm.compiler.hotspot.nodes.profiling.RandomSeedNode in project graal by oracle.

the class FinalizeProfileNodesPhase method assignRandomSources.

private static void assignRandomSources(StructuredGraph graph) {
    ValueNode seed = graph.unique(new RandomSeedNode());
    ControlFlowGraph cfg = ControlFlowGraph.compute(graph, false, true, false, false);
    Map<LoopBeginNode, ValueNode> loopRandomValueCache = new HashMap<>();
    for (ProfileNode node : getProfileNodes(graph)) {
        ValueNode random;
        Block block = cfg.blockFor(node);
        Loop<Block> loop = block.getLoop();
        // pseudo-random number generator into the loop
        if (loop != null) {
            LoopBeginNode loopBegin = (LoopBeginNode) loop.getHeader().getBeginNode();
            random = loopRandomValueCache.get(loopBegin);
            if (random == null) {
                PhiNode phi = graph.addWithoutUnique(new ValuePhiNode(seed.stamp(NodeView.DEFAULT), loopBegin));
                phi.addInput(seed);
                // X_{n+1} = a*X_n + c, using glibc-like constants
                ValueNode a = ConstantNode.forInt(1103515245, graph);
                ValueNode c = ConstantNode.forInt(12345, graph);
                ValueNode next = graph.addOrUniqueWithInputs(new AddNode(c, new MulNode(phi, a)));
                for (int i = 0; i < loopBegin.getLoopEndCount(); i++) {
                    phi.addInput(next);
                }
                random = phi;
                loopRandomValueCache.put(loopBegin, random);
            }
        } else {
            // Graal doesn't compile methods with irreducible loops. So all profile nodes that
            // are not in a loop are guaranteed to be executed at most once. We feed the seed
            // value to such nodes directly.
            random = seed;
        }
        node.setRandom(random);
    }
}