/*
 * Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved.
 * 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 com.oracle.graal.compiler.common.type;

import static com.oracle.graal.compiler.common.calc.FloatConvert.*;

import java.nio.*;
import java.util.*;

import com.oracle.graal.api.code.*;
import com.oracle.graal.api.meta.*;
import com.oracle.graal.compiler.common.spi.*;
import com.oracle.graal.compiler.common.type.ArithmeticOpTable.BinaryOp;
import com.oracle.graal.compiler.common.type.ArithmeticOpTable.FloatConvertOp;
import com.oracle.graal.compiler.common.type.ArithmeticOpTable.IntegerConvertOp;
import com.oracle.graal.compiler.common.type.ArithmeticOpTable.ShiftOp;
import com.oracle.graal.compiler.common.type.ArithmeticOpTable.UnaryOp;
import com.oracle.jvmci.common.*;

/**
 * Describes the possible values of a node that produces an int or long result.
 *
 * The description consists of (inclusive) lower and upper bounds and up (may be set) and down
 * (always set) bit-masks.
 */
public class IntegerStamp extends PrimitiveStamp {

    private final long lowerBound;
    private final long upperBound;
    private final long downMask;
    private final long upMask;

    public IntegerStamp(int bits, long lowerBound, long upperBound, long downMask, long upMask) {
        super(bits, OPS);
        this.lowerBound = lowerBound;
        this.upperBound = upperBound;
        this.downMask = downMask;
        this.upMask = upMask;
        assert lowerBound >= CodeUtil.minValue(bits) : this;
        assert upperBound <= CodeUtil.maxValue(bits) : this;
        assert (downMask & CodeUtil.mask(bits)) == downMask : this;
        assert (upMask & CodeUtil.mask(bits)) == upMask : this;
    }

    public static IntegerStamp stampForMask(int bits, long downMask, long upMask) {
        long lowerBound;
        long upperBound;
        if (((upMask >>> (bits - 1)) & 1) == 0) {
            lowerBound = downMask;
            upperBound = upMask;
        } else if (((downMask >>> (bits - 1)) & 1) == 1) {
            lowerBound = downMask;
            upperBound = upMask;
        } else {
            lowerBound = downMask | (-1L << (bits - 1));
            upperBound = CodeUtil.maxValue(bits) & upMask;
        }
        lowerBound = CodeUtil.convert(lowerBound, bits, false);
        upperBound = CodeUtil.convert(upperBound, bits, false);
        return new IntegerStamp(bits, lowerBound, upperBound, downMask, upMask);
    }

    @Override
    public IntegerStamp unrestricted() {
        return new IntegerStamp(getBits(), CodeUtil.minValue(getBits()), CodeUtil.maxValue(getBits()), 0, CodeUtil.mask(getBits()));
    }

    @Override
    public Stamp empty() {
        return new IntegerStamp(getBits(), CodeUtil.maxValue(getBits()), CodeUtil.minValue(getBits()), CodeUtil.mask(getBits()), 0);
    }

    @Override
    public Stamp constant(Constant c, MetaAccessProvider meta) {
        if (c instanceof PrimitiveConstant) {
            long value = ((PrimitiveConstant) c).asLong();
            return StampFactory.forInteger(getBits(), value, value);
        }
        return this;
    }

    @Override
    public SerializableConstant deserialize(ByteBuffer buffer) {
        switch (getBits()) {
            case 1:
                return JavaConstant.forBoolean(buffer.get() != 0);
            case 8:
                return JavaConstant.forByte(buffer.get());
            case 16:
                return JavaConstant.forShort(buffer.getShort());
            case 32:
                return JavaConstant.forInt(buffer.getInt());
            case 64:
                return JavaConstant.forLong(buffer.getLong());
            default:
                throw JVMCIError.shouldNotReachHere();
        }
    }

    @Override
    public boolean hasValues() {
        return lowerBound <= upperBound;
    }

    @Override
    public Kind getStackKind() {
        if (getBits() > 32) {
            return Kind.Long;
        } else {
            return Kind.Int;
        }
    }

    @Override
    public LIRKind getLIRKind(LIRKindTool tool) {
        return tool.getIntegerKind(getBits());
    }

    @Override
    public ResolvedJavaType javaType(MetaAccessProvider metaAccess) {
        switch (getBits()) {
            case 1:
                return metaAccess.lookupJavaType(Boolean.TYPE);
            case 8:
                return metaAccess.lookupJavaType(Byte.TYPE);
            case 16:
                return metaAccess.lookupJavaType(Short.TYPE);
            case 32:
                return metaAccess.lookupJavaType(Integer.TYPE);
            case 64:
                return metaAccess.lookupJavaType(Long.TYPE);
            default:
                throw JVMCIError.shouldNotReachHere();
        }
    }

    /**
     * The signed inclusive lower bound on the value described by this stamp.
     */
    public long lowerBound() {
        return lowerBound;
    }

    /**
     * The signed inclusive upper bound on the value described by this stamp.
     */
    public long upperBound() {
        return upperBound;
    }

    /**
     * This bit-mask describes the bits that are always set in the value described by this stamp.
     */
    public long downMask() {
        return downMask;
    }

    /**
     * This bit-mask describes the bits that can be set in the value described by this stamp.
     */
    public long upMask() {
        return upMask;
    }

    public boolean isUnrestricted() {
        return lowerBound == CodeUtil.minValue(getBits()) && upperBound == CodeUtil.maxValue(getBits()) && downMask == 0 && upMask == CodeUtil.mask(getBits());
    }

    public boolean contains(long value) {
        return value >= lowerBound && value <= upperBound && (value & downMask) == downMask && (value & upMask) == (value & CodeUtil.mask(getBits()));
    }

    public boolean isPositive() {
        return lowerBound() >= 0;
    }

    public boolean isNegative() {
        return upperBound() <= 0;
    }

    public boolean isStrictlyPositive() {
        return lowerBound() > 0;
    }

    public boolean isStrictlyNegative() {
        return upperBound() < 0;
    }

    public boolean canBePositive() {
        return upperBound() > 0;
    }

    public boolean canBeNegative() {
        return lowerBound() < 0;
    }

    @Override
    public String toString() {
        StringBuilder str = new StringBuilder();
        str.append('i');
        str.append(getBits());
        if (lowerBound == upperBound) {
            str.append(" [").append(lowerBound).append(']');
        } else if (lowerBound != CodeUtil.minValue(getBits()) || upperBound != CodeUtil.maxValue(getBits())) {
            str.append(" [").append(lowerBound).append(" - ").append(upperBound).append(']');
        }
        if (downMask != 0) {
            str.append(" \u21ca");
            new Formatter(str).format("%016x", downMask);
        }
        if (upMask != CodeUtil.mask(getBits())) {
            str.append(" \u21c8");
            new Formatter(str).format("%016x", upMask);
        }
        return str.toString();
    }

    private Stamp createStamp(IntegerStamp other, long newUpperBound, long newLowerBound, long newDownMask, long newUpMask) {
        assert getBits() == other.getBits();
        if (newLowerBound > newUpperBound || (newDownMask & (~newUpMask)) != 0 || (newUpMask == 0 && (newLowerBound > 0 || newUpperBound < 0))) {
            return empty();
        } else if (newLowerBound == lowerBound && newUpperBound == upperBound && newDownMask == downMask && newUpMask == upMask) {
            return this;
        } else if (newLowerBound == other.lowerBound && newUpperBound == other.upperBound && newDownMask == other.downMask && newUpMask == other.upMask) {
            return other;
        } else {
            return new IntegerStamp(getBits(), newLowerBound, newUpperBound, newDownMask, newUpMask);
        }
    }

    @Override
    public Stamp meet(Stamp otherStamp) {
        if (otherStamp == this) {
            return this;
        }
        IntegerStamp other = (IntegerStamp) otherStamp;
        return createStamp(other, Math.max(upperBound, other.upperBound), Math.min(lowerBound, other.lowerBound), downMask & other.downMask, upMask | other.upMask);
    }

    @Override
    public Stamp join(Stamp otherStamp) {
        if (otherStamp == this) {
            return this;
        }
        IntegerStamp other = (IntegerStamp) otherStamp;
        long newDownMask = downMask | other.downMask;
        long newLowerBound = Math.max(lowerBound, other.lowerBound) | newDownMask;
        return createStamp(other, Math.min(upperBound, other.upperBound), newLowerBound, newDownMask, upMask & other.upMask);
    }

    @Override
    public boolean isCompatible(Stamp stamp) {
        if (this == stamp) {
            return true;
        }
        if (stamp instanceof IntegerStamp) {
            IntegerStamp other = (IntegerStamp) stamp;
            return getBits() == other.getBits();
        }
        return false;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + super.hashCode();
        result = prime * result + (int) (lowerBound ^ (lowerBound >>> 32));
        result = prime * result + (int) (upperBound ^ (upperBound >>> 32));
        result = prime * result + (int) (downMask ^ (downMask >>> 32));
        result = prime * result + (int) (upMask ^ (upMask >>> 32));
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null || getClass() != obj.getClass() || !super.equals(obj)) {
            return false;
        }
        IntegerStamp other = (IntegerStamp) obj;
        if (lowerBound != other.lowerBound || upperBound != other.upperBound || downMask != other.downMask || upMask != other.upMask) {
            return false;
        }
        return super.equals(other);
    }

    public static long upMaskFor(int bits, long lowerBound, long upperBound) {
        long mask = lowerBound | upperBound;
        if (mask == 0) {
            return 0;
        } else {
            return ((-1L) >>> Long.numberOfLeadingZeros(mask)) & CodeUtil.mask(bits);
        }
    }

    /**
     * Checks if the 2 stamps represent values of the same sign. Returns true if the two stamps are
     * both positive of null or if they are both strictly negative
     *
     * @return true if the two stamps are both positive of null or if they are both strictly
     *         negative
     */
    public static boolean sameSign(IntegerStamp s1, IntegerStamp s2) {
        return s1.isPositive() && s2.isPositive() || s1.isStrictlyNegative() && s2.isStrictlyNegative();
    }

    @Override
    public JavaConstant asConstant() {
        if (lowerBound == upperBound) {
            switch (getBits()) {
                case 1:
                    return JavaConstant.forBoolean(lowerBound != 0);
                case 8:
                    return JavaConstant.forByte((byte) lowerBound);
                case 16:
                    return JavaConstant.forShort((short) lowerBound);
                case 32:
                    return JavaConstant.forInt((int) lowerBound);
                case 64:
                    return JavaConstant.forLong(lowerBound);
            }
        }
        return null;
    }

    private static boolean addOverflowsPositively(long x, long y, int bits) {
        long result = x + y;
        if (bits == 64) {
            return (~x & ~y & result) < 0;
        } else {
            return result > CodeUtil.maxValue(bits);
        }
    }

    private static boolean addOverflowsNegatively(long x, long y, int bits) {
        long result = x + y;
        if (bits == 64) {
            return (x & y & ~result) < 0;
        } else {
            return result < CodeUtil.minValue(bits);
        }
    }

    private static long carryBits(long x, long y) {
        return (x + y) ^ x ^ y;
    }

    private static long saturate(long v, int bits) {
        if (bits < 64) {
            long max = CodeUtil.maxValue(bits);
            if (v > max) {
                return max;
            }
            long min = CodeUtil.minValue(bits);
            if (v < min) {
                return min;
            }
        }
        return v;
    }

    public static final ArithmeticOpTable OPS = new ArithmeticOpTable(

    new UnaryOp.Neg() {

        @Override
        public Constant foldConstant(Constant value) {
            PrimitiveConstant c = (PrimitiveConstant) value;
            return JavaConstant.forIntegerKind(c.getKind(), -c.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp s) {
            IntegerStamp stamp = (IntegerStamp) s;
            int bits = stamp.getBits();
            if (stamp.lowerBound() != CodeUtil.minValue(bits)) {
                // TODO(ls) check if the mask calculation is correct...
                return StampFactory.forInteger(bits, -stamp.upperBound(), -stamp.lowerBound());
            } else {
                return stamp.unrestricted();
            }
        }
    },

    new BinaryOp.Add(true, true) {

        @Override
        public Constant foldConstant(Constant const1, Constant const2) {
            PrimitiveConstant a = (PrimitiveConstant) const1;
            PrimitiveConstant b = (PrimitiveConstant) const2;
            assert a.getKind() == b.getKind();
            return JavaConstant.forIntegerKind(a.getKind(), a.asLong() + b.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp stamp1, Stamp stamp2) {
            IntegerStamp a = (IntegerStamp) stamp1;
            IntegerStamp b = (IntegerStamp) stamp2;

            int bits = a.getBits();
            assert bits == b.getBits();

            if (a.isUnrestricted()) {
                return a;
            } else if (b.isUnrestricted()) {
                return b;
            }
            long defaultMask = CodeUtil.mask(bits);
            long variableBits = (a.downMask() ^ a.upMask()) | (b.downMask() ^ b.upMask());
            long variableBitsWithCarry = variableBits | (carryBits(a.downMask(), b.downMask()) ^ carryBits(a.upMask(), b.upMask()));
            long newDownMask = (a.downMask() + b.downMask()) & ~variableBitsWithCarry;
            long newUpMask = (a.downMask() + b.downMask()) | variableBitsWithCarry;

            newDownMask &= defaultMask;
            newUpMask &= defaultMask;

            long newLowerBound;
            long newUpperBound;
            boolean lowerOverflowsPositively = addOverflowsPositively(a.lowerBound(), b.lowerBound(), bits);
            boolean upperOverflowsPositively = addOverflowsPositively(a.upperBound(), b.upperBound(), bits);
            boolean lowerOverflowsNegatively = addOverflowsNegatively(a.lowerBound(), b.lowerBound(), bits);
            boolean upperOverflowsNegatively = addOverflowsNegatively(a.upperBound(), b.upperBound(), bits);
            if ((lowerOverflowsNegatively && !upperOverflowsNegatively) || (!lowerOverflowsPositively && upperOverflowsPositively)) {
                newLowerBound = CodeUtil.minValue(bits);
                newUpperBound = CodeUtil.maxValue(bits);
            } else {
                newLowerBound = CodeUtil.signExtend((a.lowerBound() + b.lowerBound()) & defaultMask, bits);
                newUpperBound = CodeUtil.signExtend((a.upperBound() + b.upperBound()) & defaultMask, bits);
            }
            IntegerStamp limit = StampFactory.forInteger(bits, newLowerBound, newUpperBound);
            newUpMask &= limit.upMask();
            newUpperBound = CodeUtil.signExtend(newUpperBound & newUpMask, bits);
            newDownMask |= limit.downMask();
            newLowerBound |= newDownMask;
            return new IntegerStamp(bits, newLowerBound, newUpperBound, newDownMask, newUpMask);
        }

        @Override
        public boolean isNeutral(Constant value) {
            PrimitiveConstant n = (PrimitiveConstant) value;
            return n.asLong() == 0;
        }
    },

    new BinaryOp.Sub(true, false) {

        @Override
        public Constant foldConstant(Constant const1, Constant const2) {
            PrimitiveConstant a = (PrimitiveConstant) const1;
            PrimitiveConstant b = (PrimitiveConstant) const2;
            assert a.getKind() == b.getKind();
            return JavaConstant.forIntegerKind(a.getKind(), a.asLong() - b.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp a, Stamp b) {
            return OPS.getAdd().foldStamp(a, OPS.getNeg().foldStamp(b));
        }

        @Override
        public boolean isNeutral(Constant value) {
            PrimitiveConstant n = (PrimitiveConstant) value;
            return n.asLong() == 0;
        }

        @Override
        public Constant getZero(Stamp s) {
            IntegerStamp stamp = (IntegerStamp) s;
            return JavaConstant.forPrimitiveInt(stamp.getBits(), 0);
        }
    },

    new BinaryOp.Mul(true, true) {

        @Override
        public Constant foldConstant(Constant const1, Constant const2) {
            PrimitiveConstant a = (PrimitiveConstant) const1;
            PrimitiveConstant b = (PrimitiveConstant) const2;
            assert a.getKind() == b.getKind();
            return JavaConstant.forIntegerKind(a.getKind(), a.asLong() * b.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp stamp1, Stamp stamp2) {
            IntegerStamp a = (IntegerStamp) stamp1;
            IntegerStamp b = (IntegerStamp) stamp2;
            if (a.upMask() == 0) {
                return a;
            } else if (b.upMask() == 0) {
                return b;
            } else {
                // TODO
                return a.unrestricted();
            }
        }

        @Override
        public boolean isNeutral(Constant value) {
            PrimitiveConstant n = (PrimitiveConstant) value;
            return n.asLong() == 1;
        }
    },

    new BinaryOp.Div(true, false) {

        @Override
        public Constant foldConstant(Constant const1, Constant const2) {
            PrimitiveConstant a = (PrimitiveConstant) const1;
            PrimitiveConstant b = (PrimitiveConstant) const2;
            assert a.getKind() == b.getKind();
            return JavaConstant.forIntegerKind(a.getKind(), a.asLong() / b.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp stamp1, Stamp stamp2) {
            IntegerStamp a = (IntegerStamp) stamp1;
            IntegerStamp b = (IntegerStamp) stamp2;
            assert a.getBits() == b.getBits();
            if (b.isStrictlyPositive()) {
                long newLowerBound = a.lowerBound() / b.lowerBound();
                long newUpperBound = a.upperBound() / b.lowerBound();
                return StampFactory.forInteger(a.getBits(), newLowerBound, newUpperBound);
            } else {
                return a.unrestricted();
            }
        }

        @Override
        public boolean isNeutral(Constant value) {
            PrimitiveConstant n = (PrimitiveConstant) value;
            return n.asLong() == 1;
        }
    },

    new BinaryOp.Rem(false, false) {

        @Override
        public Constant foldConstant(Constant const1, Constant const2) {
            PrimitiveConstant a = (PrimitiveConstant) const1;
            PrimitiveConstant b = (PrimitiveConstant) const2;
            assert a.getKind() == b.getKind();
            return JavaConstant.forIntegerKind(a.getKind(), a.asLong() % b.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp stamp1, Stamp stamp2) {
            IntegerStamp a = (IntegerStamp) stamp1;
            IntegerStamp b = (IntegerStamp) stamp2;
            assert a.getBits() == b.getBits();
            // zero is always possible
            long newLowerBound = Math.min(a.lowerBound(), 0);
            long newUpperBound = Math.max(a.upperBound(), 0);

            long magnitude; // the maximum absolute value of the result, derived from b
            if (b.lowerBound() == CodeUtil.minValue(b.getBits())) {
                // Math.abs(...) - 1 does not work in a case
                magnitude = CodeUtil.maxValue(b.getBits());
            } else {
                magnitude = Math.max(Math.abs(b.lowerBound()), Math.abs(b.upperBound())) - 1;
            }
            newLowerBound = Math.max(newLowerBound, -magnitude);
            newUpperBound = Math.min(newUpperBound, magnitude);

            return StampFactory.forInteger(a.getBits(), newLowerBound, newUpperBound);
        }
    },

    new UnaryOp.Not() {

        @Override
        public Constant foldConstant(Constant c) {
            PrimitiveConstant value = (PrimitiveConstant) c;
            return JavaConstant.forIntegerKind(value.getKind(), ~value.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp stamp) {
            IntegerStamp integerStamp = (IntegerStamp) stamp;
            int bits = integerStamp.getBits();
            long defaultMask = CodeUtil.mask(bits);
            return new IntegerStamp(bits, ~integerStamp.upperBound(), ~integerStamp.lowerBound(), (~integerStamp.upMask()) & defaultMask, (~integerStamp.downMask()) & defaultMask);
        }
    },

    new BinaryOp.And(true, true) {

        @Override
        public Constant foldConstant(Constant const1, Constant const2) {
            PrimitiveConstant a = (PrimitiveConstant) const1;
            PrimitiveConstant b = (PrimitiveConstant) const2;
            assert a.getKind() == b.getKind();
            return JavaConstant.forIntegerKind(a.getKind(), a.asLong() & b.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp stamp1, Stamp stamp2) {
            IntegerStamp a = (IntegerStamp) stamp1;
            IntegerStamp b = (IntegerStamp) stamp2;
            assert a.getBits() == b.getBits();
            return stampForMask(a.getBits(), a.downMask() & b.downMask(), a.upMask() & b.upMask());
        }

        @Override
        public boolean isNeutral(Constant value) {
            PrimitiveConstant n = (PrimitiveConstant) value;
            int bits = n.getKind().getBitCount();
            long mask = CodeUtil.mask(bits);
            return (n.asLong() & mask) == mask;
        }
    },

    new BinaryOp.Or(true, true) {

        @Override
        public Constant foldConstant(Constant const1, Constant const2) {
            PrimitiveConstant a = (PrimitiveConstant) const1;
            PrimitiveConstant b = (PrimitiveConstant) const2;
            assert a.getKind() == b.getKind();
            return JavaConstant.forIntegerKind(a.getKind(), a.asLong() | b.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp stamp1, Stamp stamp2) {
            IntegerStamp a = (IntegerStamp) stamp1;
            IntegerStamp b = (IntegerStamp) stamp2;
            assert a.getBits() == b.getBits();
            return stampForMask(a.getBits(), a.downMask() | b.downMask(), a.upMask() | b.upMask());
        }

        @Override
        public boolean isNeutral(Constant value) {
            PrimitiveConstant n = (PrimitiveConstant) value;
            return n.asLong() == 0;
        }
    },

    new BinaryOp.Xor(true, true) {

        @Override
        public Constant foldConstant(Constant const1, Constant const2) {
            PrimitiveConstant a = (PrimitiveConstant) const1;
            PrimitiveConstant b = (PrimitiveConstant) const2;
            assert a.getKind() == b.getKind();
            return JavaConstant.forIntegerKind(a.getKind(), a.asLong() ^ b.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp stamp1, Stamp stamp2) {
            IntegerStamp a = (IntegerStamp) stamp1;
            IntegerStamp b = (IntegerStamp) stamp2;
            assert a.getBits() == b.getBits();

            long variableBits = (a.downMask() ^ a.upMask()) | (b.downMask() ^ b.upMask());
            long newDownMask = (a.downMask() ^ b.downMask()) & ~variableBits;
            long newUpMask = (a.downMask() ^ b.downMask()) | variableBits;
            return stampForMask(a.getBits(), newDownMask, newUpMask);
        }

        @Override
        public boolean isNeutral(Constant value) {
            PrimitiveConstant n = (PrimitiveConstant) value;
            return n.asLong() == 0;
        }

        @Override
        public Constant getZero(Stamp s) {
            IntegerStamp stamp = (IntegerStamp) s;
            return JavaConstant.forPrimitiveInt(stamp.getBits(), 0);
        }
    },

    new ShiftOp.Shl() {

        @Override
        public Constant foldConstant(Constant value, int amount) {
            PrimitiveConstant c = (PrimitiveConstant) value;
            switch (c.getKind()) {
                case Int:
                    return JavaConstant.forInt(c.asInt() << amount);
                case Long:
                    return JavaConstant.forLong(c.asLong() << amount);
                default:
                    throw JVMCIError.shouldNotReachHere();
            }
        }

        @Override
        public Stamp foldStamp(Stamp stamp, IntegerStamp shift) {
            IntegerStamp value = (IntegerStamp) stamp;
            int bits = value.getBits();
            long defaultMask = CodeUtil.mask(bits);
            if (value.upMask() == 0) {
                return value;
            }
            int shiftMask = getShiftAmountMask(stamp);
            int shiftBits = Integer.bitCount(shiftMask);
            if (shift.lowerBound() == shift.upperBound()) {
                int shiftAmount = (int) (shift.lowerBound() & shiftMask);
                if (shiftAmount == 0) {
                    return value;
                }
                // the mask of bits that will be lost or shifted into the sign bit
                long removedBits = -1L << (bits - shiftAmount - 1);
                if ((value.lowerBound() & removedBits) == 0 && (value.upperBound() & removedBits) == 0) {
                    // use a better stamp if neither lower nor upper bound can lose bits
                    return new IntegerStamp(bits, value.lowerBound() << shiftAmount, value.upperBound() << shiftAmount, value.downMask() << shiftAmount, value.upMask() << shiftAmount);
                }
            }
            if ((shift.lowerBound() >>> shiftBits) == (shift.upperBound() >>> shiftBits)) {
                long downMask = defaultMask;
                long upMask = 0;
                for (long i = shift.lowerBound(); i <= shift.upperBound(); i++) {
                    if (shift.contains(i)) {
                        downMask &= value.downMask() << (i & shiftMask);
                        upMask |= value.upMask() << (i & shiftMask);
                    }
                }
                Stamp result = IntegerStamp.stampForMask(bits, downMask, upMask & defaultMask);
                return result;
            }
            return value.unrestricted();
        }

        @Override
        public int getShiftAmountMask(Stamp s) {
            IntegerStamp stamp = (IntegerStamp) s;
            assert CodeUtil.isPowerOf2(stamp.getBits());
            return stamp.getBits() - 1;
        }
    },

    new ShiftOp.Shr() {

        @Override
        public Constant foldConstant(Constant value, int amount) {
            PrimitiveConstant c = (PrimitiveConstant) value;
            switch (c.getKind()) {
                case Int:
                    return JavaConstant.forInt(c.asInt() >> amount);
                case Long:
                    return JavaConstant.forLong(c.asLong() >> amount);
                default:
                    throw JVMCIError.shouldNotReachHere();
            }
        }

        @Override
        public Stamp foldStamp(Stamp stamp, IntegerStamp shift) {
            IntegerStamp value = (IntegerStamp) stamp;
            int bits = value.getBits();
            if (shift.lowerBound() == shift.upperBound()) {
                long shiftCount = shift.lowerBound() & getShiftAmountMask(stamp);
                if (shiftCount == 0) {
                    return stamp;
                }

                int extraBits = 64 - bits;
                long defaultMask = CodeUtil.mask(bits);
                // shifting back and forth performs sign extension
                long downMask = (value.downMask() << extraBits) >> (shiftCount + extraBits) & defaultMask;
                long upMask = (value.upMask() << extraBits) >> (shiftCount + extraBits) & defaultMask;
                return new IntegerStamp(bits, value.lowerBound() >> shiftCount, value.upperBound() >> shiftCount, downMask, upMask);
            }
            long mask = IntegerStamp.upMaskFor(bits, value.lowerBound(), value.upperBound());
            return IntegerStamp.stampForMask(bits, 0, mask);
        }

        @Override
        public int getShiftAmountMask(Stamp s) {
            IntegerStamp stamp = (IntegerStamp) s;
            assert CodeUtil.isPowerOf2(stamp.getBits());
            return stamp.getBits() - 1;
        }
    },

    new ShiftOp.UShr() {

        @Override
        public Constant foldConstant(Constant value, int amount) {
            PrimitiveConstant c = (PrimitiveConstant) value;
            switch (c.getKind()) {
                case Int:
                    return JavaConstant.forInt(c.asInt() >>> amount);
                case Long:
                    return JavaConstant.forLong(c.asLong() >>> amount);
                default:
                    throw JVMCIError.shouldNotReachHere();
            }
        }

        @Override
        public Stamp foldStamp(Stamp stamp, IntegerStamp shift) {
            IntegerStamp value = (IntegerStamp) stamp;
            int bits = value.getBits();
            if (shift.lowerBound() == shift.upperBound()) {
                long shiftCount = shift.lowerBound() & getShiftAmountMask(stamp);
                if (shiftCount == 0) {
                    return stamp;
                }

                long downMask = value.downMask() >>> shiftCount;
                long upMask = value.upMask() >>> shiftCount;
                if (value.lowerBound() < 0) {
                    return new IntegerStamp(bits, downMask, upMask, downMask, upMask);
                } else {
                    return new IntegerStamp(bits, value.lowerBound() >>> shiftCount, value.upperBound() >>> shiftCount, downMask, upMask);
                }
            }
            long mask = IntegerStamp.upMaskFor(bits, value.lowerBound(), value.upperBound());
            return IntegerStamp.stampForMask(bits, 0, mask);
        }

        @Override
        public int getShiftAmountMask(Stamp s) {
            IntegerStamp stamp = (IntegerStamp) s;
            assert CodeUtil.isPowerOf2(stamp.getBits());
            return stamp.getBits() - 1;
        }
    },

    new UnaryOp.Abs() {

        @Override
        public Constant foldConstant(Constant value) {
            PrimitiveConstant c = (PrimitiveConstant) value;
            return JavaConstant.forIntegerKind(c.getKind(), Math.abs(c.asLong()));
        }

        @Override
        public Stamp foldStamp(Stamp input) {
            IntegerStamp stamp = (IntegerStamp) input;
            int bits = stamp.getBits();
            if (stamp.lowerBound() == CodeUtil.minValue(bits)) {
                return input.unrestricted();
            } else {
                long limit = Math.max(-stamp.lowerBound(), stamp.upperBound());
                return StampFactory.forInteger(bits, 0, limit);
            }
        }
    },

    null,

    new IntegerConvertOp.ZeroExtend() {

        @Override
        public Constant foldConstant(int inputBits, int resultBits, Constant c) {
            PrimitiveConstant value = (PrimitiveConstant) c;
            return JavaConstant.forPrimitiveInt(resultBits, CodeUtil.zeroExtend(value.asLong(), inputBits));
        }

        @Override
        public Stamp foldStamp(int inputBits, int resultBits, Stamp input) {
            IntegerStamp stamp = (IntegerStamp) input;
            assert inputBits == stamp.getBits();
            assert inputBits <= resultBits;

            long downMask = CodeUtil.zeroExtend(stamp.downMask(), inputBits);
            long upMask = CodeUtil.zeroExtend(stamp.upMask(), inputBits);

            if (stamp.lowerBound() < 0 && stamp.upperBound() >= 0) {
                // signed range including 0 and -1
                // after sign extension, the whole range from 0 to MAX_INT is possible
                return IntegerStamp.stampForMask(resultBits, downMask, upMask);
            }

            long lowerBound = CodeUtil.zeroExtend(stamp.lowerBound(), inputBits);
            long upperBound = CodeUtil.zeroExtend(stamp.upperBound(), inputBits);

            return new IntegerStamp(resultBits, lowerBound, upperBound, downMask, upMask);
        }
    },

    new IntegerConvertOp.SignExtend() {

        @Override
        public Constant foldConstant(int inputBits, int resultBits, Constant c) {
            PrimitiveConstant value = (PrimitiveConstant) c;
            return JavaConstant.forPrimitiveInt(resultBits, CodeUtil.signExtend(value.asLong(), inputBits));
        }

        @Override
        public Stamp foldStamp(int inputBits, int resultBits, Stamp input) {
            IntegerStamp stamp = (IntegerStamp) input;
            assert inputBits == stamp.getBits();
            assert inputBits <= resultBits;

            long defaultMask = CodeUtil.mask(resultBits);
            long downMask = CodeUtil.signExtend(stamp.downMask(), inputBits) & defaultMask;
            long upMask = CodeUtil.signExtend(stamp.upMask(), inputBits) & defaultMask;

            return new IntegerStamp(resultBits, stamp.lowerBound(), stamp.upperBound(), downMask, upMask);
        }
    },

    new IntegerConvertOp.Narrow() {

        @Override
        public Constant foldConstant(int inputBits, int resultBits, Constant c) {
            PrimitiveConstant value = (PrimitiveConstant) c;
            return JavaConstant.forPrimitiveInt(resultBits, CodeUtil.narrow(value.asLong(), resultBits));
        }

        @Override
        public Stamp foldStamp(int inputBits, int resultBits, Stamp input) {
            IntegerStamp stamp = (IntegerStamp) input;
            assert inputBits == stamp.getBits();
            assert resultBits <= inputBits;
            if (resultBits == inputBits) {
                return stamp;
            }

            final long upperBound;
            if (stamp.lowerBound() < CodeUtil.minValue(resultBits)) {
                upperBound = CodeUtil.maxValue(resultBits);
            } else {
                upperBound = saturate(stamp.upperBound(), resultBits);
            }
            final long lowerBound;
            if (stamp.upperBound() > CodeUtil.maxValue(resultBits)) {
                lowerBound = CodeUtil.minValue(resultBits);
            } else {
                lowerBound = saturate(stamp.lowerBound(), resultBits);
            }

            long defaultMask = CodeUtil.mask(resultBits);
            long newDownMask = stamp.downMask() & defaultMask;
            long newUpMask = stamp.upMask() & defaultMask;
            long newLowerBound = CodeUtil.signExtend((lowerBound | newDownMask) & newUpMask, resultBits);
            long newUpperBound = CodeUtil.signExtend((upperBound | newDownMask) & newUpMask, resultBits);
            return new IntegerStamp(resultBits, newLowerBound, newUpperBound, newDownMask, newUpMask);
        }
    },

    new FloatConvertOp(I2F) {

        @Override
        public Constant foldConstant(Constant c) {
            PrimitiveConstant value = (PrimitiveConstant) c;
            return JavaConstant.forFloat(value.asInt());
        }

        @Override
        public Stamp foldStamp(Stamp input) {
            IntegerStamp stamp = (IntegerStamp) input;
            assert stamp.getBits() == 32;
            float lowerBound = stamp.lowerBound();
            float upperBound = stamp.upperBound();
            return StampFactory.forFloat(Kind.Float, lowerBound, upperBound, true);
        }
    },

    new FloatConvertOp(L2F) {

        @Override
        public Constant foldConstant(Constant c) {
            PrimitiveConstant value = (PrimitiveConstant) c;
            return JavaConstant.forFloat(value.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp input) {
            IntegerStamp stamp = (IntegerStamp) input;
            assert stamp.getBits() == 64;
            float lowerBound = stamp.lowerBound();
            float upperBound = stamp.upperBound();
            return StampFactory.forFloat(Kind.Float, lowerBound, upperBound, true);
        }
    },

    new FloatConvertOp(I2D) {

        @Override
        public Constant foldConstant(Constant c) {
            PrimitiveConstant value = (PrimitiveConstant) c;
            return JavaConstant.forDouble(value.asInt());
        }

        @Override
        public Stamp foldStamp(Stamp input) {
            IntegerStamp stamp = (IntegerStamp) input;
            assert stamp.getBits() == 32;
            double lowerBound = stamp.lowerBound();
            double upperBound = stamp.upperBound();
            return StampFactory.forFloat(Kind.Double, lowerBound, upperBound, true);
        }
    },

    new FloatConvertOp(L2D) {

        @Override
        public Constant foldConstant(Constant c) {
            PrimitiveConstant value = (PrimitiveConstant) c;
            return JavaConstant.forDouble(value.asLong());
        }

        @Override
        public Stamp foldStamp(Stamp input) {
            IntegerStamp stamp = (IntegerStamp) input;
            assert stamp.getBits() == 64;
            double lowerBound = stamp.lowerBound();
            double upperBound = stamp.upperBound();
            return StampFactory.forFloat(Kind.Double, lowerBound, upperBound, true);
        }
    });
}