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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package org.graalvm.compiler.nodes.calc;

import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_1;

import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1;

import org.graalvm.compiler.core.common.type.ArithmeticOpTable;

import org.graalvm.compiler.core.common.type.ArithmeticOpTable.BinaryOp;

import org.graalvm.compiler.core.common.type.IntegerStamp;

import org.graalvm.compiler.core.common.type.Stamp;

import org.graalvm.compiler.debug.GraalError;

import org.graalvm.compiler.graph.Graph;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.graph.NodeClass;

import org.graalvm.compiler.graph.iterators.NodePredicate;

import org.graalvm.compiler.graph.spi.Canonicalizable;

import org.graalvm.compiler.graph.spi.CanonicalizerTool;

import org.graalvm.compiler.nodeinfo.NodeInfo;

import org.graalvm.compiler.nodes.ArithmeticOperation;

import org.graalvm.compiler.nodes.ConstantNode;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.ValuePhiNode;

import org.graalvm.compiler.nodes.spi.ArithmeticLIRLowerable;

import org.graalvm.compiler.nodes.spi.NodeValueMap;

import jdk.vm.ci.meta.Constant;

@NodeInfo(cycles = CYCLES_1, size = SIZE_1)

public abstract class BinaryArithmeticNode<OP> extends BinaryNode implements ArithmeticOperation, ArithmeticLIRLowerable, Canonicalizable.Binary<ValueNode> {

    @SuppressWarnings("rawtypes") public static final NodeClass<BinaryArithmeticNode> TYPE = NodeClass.create(BinaryArithmeticNode.class);

    }

    }

    protected final BinaryOp<OP> getOp(ValueNode forX, ValueNode forY) {

    }

    @Override

    public final BinaryOp<OP> getArithmeticOp() {

        return getOp(getX(), getY());

    }

    public boolean isAssociative() {

        return getArithmeticOp().isAssociative();

    }

    @Override

    public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {

        NodeView view = NodeView.from(tool);

        ValueNode result = tryConstantFold(getOp(forX, forY), forX, forY, stamp(view), view);

        if (result != null) {

            return result;

        }

        if (forX instanceof ConditionalNode && forY.isConstant() && forX.hasExactlyOneUsage()) {

            ConditionalNode conditionalNode = (ConditionalNode) forX;

            BinaryOp<OP> arithmeticOp = getArithmeticOp();

            ConstantNode trueConstant = tryConstantFold(arithmeticOp, conditionalNode.trueValue(), forY, this.stamp(view), view);

            if (trueConstant != null) {

                ConstantNode falseConstant = tryConstantFold(arithmeticOp, conditionalNode.falseValue(), forY, this.stamp(view), view);

                if (falseConstant != null) {

                    // @formatter:off

                    /* The arithmetic is folded into a constant on both sides of the conditional.

                     * Example:

                     *            (cond ? -5 : 5) + 100

                     * canonicalizes to:

                     *            (cond ? 95 : 105)

                     */

                    // @formatter:on

                    return ConditionalNode.create(conditionalNode.condition, trueConstant,

                                    falseConstant, view);

                }

            }

        }

        return this;

    }

    @SuppressWarnings("unused")

    public static <OP> ConstantNode tryConstantFold(BinaryOp<OP> op, ValueNode forX, ValueNode forY, Stamp stamp, NodeView view) {

        if (forX.isConstant() && forY.isConstant()) {

            Constant ret = op.foldConstant(forX.asConstant(), forY.asConstant());

            if (ret != null) {

                return ConstantNode.forPrimitive(stamp, ret);

            }

        }

        return null;

    }

    @Override

    public Stamp foldStamp(Stamp stampX, Stamp stampY) {

        assert stampX.isCompatible(x.stamp(NodeView.DEFAULT)) && stampY.isCompatible(y.stamp(NodeView.DEFAULT));

        return getArithmeticOp().foldStamp(stampX, stampY);

    }

    public static ValueNode add(StructuredGraph graph, ValueNode v1, ValueNode v2, NodeView view) {

        return graph.addOrUniqueWithInputs(AddNode.create(v1, v2, view));

    }

    public static ValueNode add(ValueNode v1, ValueNode v2, NodeView view) {

        return AddNode.create(v1, v2, view);

    }

    public static ValueNode add(ValueNode v1, ValueNode v2) {

        return add(v1, v2, NodeView.DEFAULT);

    }

    public static ValueNode mul(StructuredGraph graph, ValueNode v1, ValueNode v2, NodeView view) {

        return graph.addOrUniqueWithInputs(MulNode.create(v1, v2, view));

    }

    public static ValueNode mul(ValueNode v1, ValueNode v2, NodeView view) {

        return MulNode.create(v1, v2, view);

    }

    public static ValueNode mul(ValueNode v1, ValueNode v2) {

        return mul(v1, v2, NodeView.DEFAULT);

    }

    public static ValueNode sub(StructuredGraph graph, ValueNode v1, ValueNode v2, NodeView view) {

        return graph.addOrUniqueWithInputs(SubNode.create(v1, v2, view));

    }

    public static ValueNode sub(ValueNode v1, ValueNode v2, NodeView view) {

        return SubNode.create(v1, v2, view);

    }

    public static ValueNode sub(ValueNode v1, ValueNode v2) {

        return sub(v1, v2, NodeView.DEFAULT);

    }

    public static ValueNode branchlessMin(ValueNode v1, ValueNode v2, NodeView view) {

        if (v1.isDefaultConstant() && !v2.isDefaultConstant()) {

            return branchlessMin(v2, v1, view);

        }

        int bits = ((IntegerStamp) v1.stamp(view)).getBits();

        assert ((IntegerStamp) v2.stamp(view)).getBits() == bits;

        ValueNode t1 = sub(v1, v2, view);

        ValueNode t2 = RightShiftNode.create(t1, bits - 1, view);

        ValueNode t3 = AndNode.create(t1, t2, view);

        return add(v2, t3, view);

    }

    public static ValueNode branchlessMax(ValueNode v1, ValueNode v2, NodeView view) {

        if (v1.isDefaultConstant() && !v2.isDefaultConstant()) {

            return branchlessMax(v2, v1, view);

        }

        int bits = ((IntegerStamp) v1.stamp(view)).getBits();

        assert ((IntegerStamp) v2.stamp(view)).getBits() == bits;

        if (v2.isDefaultConstant()) {

            // prefer a & ~(a>>31) to a - (a & (a>>31))

            return AndNode.create(v1, NotNode.create(RightShiftNode.create(v1, bits - 1, view)), view);

        } else {

            ValueNode t1 = sub(v1, v2, view);

            ValueNode t2 = RightShiftNode.create(t1, bits - 1, view);

            ValueNode t3 = AndNode.create(t1, t2, view);

            return sub(v1, t3, view);

        }

    }

    private enum ReassociateMatch {

        x,

        y;

        public ValueNode getValue(BinaryNode binary) {

            switch (this) {

                case x:

                    return binary.getX();

                case y:

                    return binary.getY();

                default:

                    throw GraalError.shouldNotReachHere();

            }

        }

        public ValueNode getOtherValue(BinaryNode binary) {

            switch (this) {

                case x:

                    return binary.getY();

                case y:

                    return binary.getX();

                default:

                    throw GraalError.shouldNotReachHere();

            }

        }

    }

    private static ReassociateMatch findReassociate(BinaryNode binary, NodePredicate criterion) {

        boolean resultX = criterion.apply(binary.getX());

        boolean resultY = criterion.apply(binary.getY());

        if (resultX && !resultY) {

            return ReassociateMatch.x;

        }

        if (!resultX && resultY) {

            return ReassociateMatch.y;

        }

        return null;

    }

    //@formatter:off

    /*

     * In reassociate, complexity comes from the handling of IntegerSub (non commutative) which can

     * be mixed with IntegerAdd. It first tries to find m1, m2 which match the criterion :

     * (a o m2) o m1

     * (m2 o a) o m1

     * m1 o (a o m2)

     * m1 o (m2 o a)

     * It then produces 4 boolean for the -/+ cases:

     * invertA : should the final expression be like *-a (rather than a+*)

     * aSub : should the final expression be like a-* (rather than a+*)

     * invertM1 : should the final expression contain -m1

     * invertM2 : should the final expression contain -m2

     *

     */

    //@formatter:on

    /**

     * Tries to re-associate values which satisfy the criterion. For example with a constantness

     * criterion: {@code (a + 2) + 1 => a + (1 + 2)}

     * <p>

     * This method accepts only {@linkplain BinaryOp#isAssociative() associative} operations such as

     * +, -, *, &, | and ^

     *

     * @param forY

     * @param forX

     */

    public static ValueNode reassociate(BinaryArithmeticNode<?> node, NodePredicate criterion, ValueNode forX, ValueNode forY, NodeView view) {

        assert node.getOp(forX, forY).isAssociative();

        ReassociateMatch match1 = findReassociate(node, criterion);

        if (match1 == null) {

            return node;

        }

        ValueNode otherValue = match1.getOtherValue(node);

        boolean addSub = false;

        boolean subAdd = false;

        if (otherValue.getClass() != node.getClass()) {

            if (node instanceof AddNode && otherValue instanceof SubNode) {

                addSub = true;

            } else if (node instanceof SubNode && otherValue instanceof AddNode) {

                subAdd = true;

            } else {

                return node;

            }

        }

        BinaryNode other = (BinaryNode) otherValue;

        ReassociateMatch match2 = findReassociate(other, criterion);

        if (match2 == null) {

            return node;

        }

        boolean invertA = false;

        boolean aSub = false;

        boolean invertM1 = false;

        boolean invertM2 = false;

        if (addSub) {

            invertM2 = match2 == ReassociateMatch.y;

            invertA = !invertM2;

        } else if (subAdd) {

            invertA = invertM2 = match1 == ReassociateMatch.x;

            invertM1 = !invertM2;

        } else if (node instanceof SubNode && other instanceof SubNode) {

            invertA = match1 == ReassociateMatch.x ^ match2 == ReassociateMatch.x;

            aSub = match1 == ReassociateMatch.y && match2 == ReassociateMatch.y;

            invertM1 = match1 == ReassociateMatch.y && match2 == ReassociateMatch.x;

            invertM2 = match1 == ReassociateMatch.x && match2 == ReassociateMatch.x;

        }

        assert !(invertM1 && invertM2) && !(invertA && aSub);

        ValueNode m1 = match1.getValue(node);

        ValueNode m2 = match2.getValue(other);

        ValueNode a = match2.getOtherValue(other);

        if (node instanceof AddNode || node instanceof SubNode) {

            ValueNode associated;

            if (invertM1) {

                associated = BinaryArithmeticNode.sub(m2, m1, view);

            } else if (invertM2) {

                associated = BinaryArithmeticNode.sub(m1, m2, view);

            } else {

                associated = BinaryArithmeticNode.add(m1, m2, view);

            }

            if (invertA) {

                return BinaryArithmeticNode.sub(associated, a, view);

            }

            if (aSub) {

                return BinaryArithmeticNode.sub(a, associated, view);

            }

            return BinaryArithmeticNode.add(a, associated, view);

        } else if (node instanceof MulNode) {

            return BinaryArithmeticNode.mul(a, AddNode.mul(m1, m2, view), view);

        } else if (node instanceof AndNode) {

            return new AndNode(a, new AndNode(m1, m2));

        } else if (node instanceof OrNode) {

            return new OrNode(a, new OrNode(m1, m2));

        } else if (node instanceof XorNode) {

            return new XorNode(a, new XorNode(m1, m2));

        } else {

            throw GraalError.shouldNotReachHere();

        }

    }

    /**

     * Ensure a canonical ordering of inputs for commutative nodes to improve GVN results. Order the

     * inputs by increasing {@link Node#id} and call {@link Graph#findDuplicate(Node)} on the node

     * if it's currently in a graph. It's assumed that if there was a constant on the left it's been

     * moved to the right by other code and that ordering is left alone.

     *

     * @return the original node or another node with the same input ordering

     */

    @SuppressWarnings("deprecation")

    public BinaryNode maybeCommuteInputs() {

        assert this instanceof BinaryCommutative;

        if (!y.isConstant() && (x.isConstant() || x.getId() > y.getId())) {

            ValueNode tmp = x;

            x = y;

            y = tmp;

            if (graph() != null) {

                // See if this node already exists

                BinaryNode duplicate = graph().findDuplicate(this);

                if (duplicate != null) {

                    return duplicate;

                }

            }

        }

        return this;

    }

    /**

     * Determines if it would be better to swap the inputs in order to produce better assembly code.

     * First we try to pick a value which is dead after this use. If both values are dead at this

     * use then we try pick an induction variable phi to encourage the phi to live in a single

     * register.

     *

     * @param nodeValueMap

     * @return true if inputs should be swapped, false otherwise

     */

    protected boolean shouldSwapInputs(NodeValueMap nodeValueMap) {

        final boolean xHasOtherUsages = getX().hasUsagesOtherThan(this, nodeValueMap);

        final boolean yHasOtherUsages = getY().hasUsagesOtherThan(this, nodeValueMap);

        if (!getY().isConstant() && !yHasOtherUsages) {

            if (xHasOtherUsages == yHasOtherUsages) {

                return getY() instanceof ValuePhiNode && getY().inputs().contains(this);

            } else {

                return true;

            }

        }

        return false;

    }

}