/*

 * Copyright (c) 2013, 2014, 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.

 *

 */

#include "precompiled.hpp"

#include "memory/allocation.inline.hpp"

#include "opto/addnode.hpp"

#include "opto/cfgnode.hpp"

#include "opto/machnode.hpp"

#include "opto/matcher.hpp"

#include "opto/mathexactnode.hpp"

#include "opto/subnode.hpp"

template <typename OverflowOp>

class AddHelper {

public:

  typedef typename OverflowOp::TypeClass TypeClass;

  typedef typename TypeClass::NativeType NativeType;

  static bool will_overflow(NativeType value1, NativeType value2) {

    NativeType result = value1 + value2;

    // Hacker's Delight 2-12 Overflow if both arguments have the opposite sign of the result

    if (((value1 ^ result) & (value2 ^ result)) >= 0) {

      return false;

    }

    return true;

  }

  static bool can_overflow(const Type* type1, const Type* type2) {

    if (type1 == TypeClass::ZERO || type2 == TypeClass::ZERO) {

      return false;

    }

    return true;

  }

};

template <typename OverflowOp>

class SubHelper {

public:

  typedef typename OverflowOp::TypeClass TypeClass;

  typedef typename TypeClass::NativeType NativeType;

  static bool will_overflow(NativeType value1, NativeType value2) {

    NativeType result = value1 - value2;

    // hacker's delight 2-12 overflow iff the arguments have different signs and

    // the sign of the result is different than the sign of arg1

    if (((value1 ^ value2) & (value1 ^ result)) >= 0) {

      return false;

    }

    return true;

  }

  static bool can_overflow(const Type* type1, const Type* type2) {

    if (type2 == TypeClass::ZERO) {

      return false;

    }

    return true;

  }

};

template <typename OverflowOp>

class MulHelper {

public:

  typedef typename OverflowOp::TypeClass TypeClass;

  static bool can_overflow(const Type* type1, const Type* type2) {

    if (type1 == TypeClass::ZERO || type2 == TypeClass::ZERO) {

      return false;

    } else if (type1 == TypeClass::ONE || type2 == TypeClass::ONE) {

      return false;

    }

    return true;

  }

};

bool OverflowAddINode::will_overflow(jint v1, jint v2) const {

  return AddHelper<OverflowAddINode>::will_overflow(v1, v2);

}

bool OverflowSubINode::will_overflow(jint v1, jint v2) const {

  return SubHelper<OverflowSubINode>::will_overflow(v1, v2);

}

bool OverflowMulINode::will_overflow(jint v1, jint v2) const {

    jlong result = (jlong) v1 * (jlong) v2;

    if ((jint) result == result) {

      return false;

    }

    return true;

}

bool OverflowAddLNode::will_overflow(jlong v1, jlong v2) const {

  return AddHelper<OverflowAddLNode>::will_overflow(v1, v2);

}

bool OverflowSubLNode::will_overflow(jlong v1, jlong v2) const {

  return SubHelper<OverflowSubLNode>::will_overflow(v1, v2);

}

bool OverflowMulLNode::will_overflow(jlong val1, jlong val2) const {

    jlong result = val1 * val2;

    jlong ax = (val1 < 0 ? -val1 : val1);

    jlong ay = (val2 < 0 ? -val2 : val2);

    bool overflow = false;

    if ((ax | ay) & CONST64(0xFFFFFFFF00000000)) {

      // potential overflow if any bit in upper 32 bits are set

      if ((val1 == min_jlong && val2 == -1) || (val2 == min_jlong && val1 == -1)) {

        // -1 * Long.MIN_VALUE will overflow

        overflow = true;

      } else if (val2 != 0 && (result / val2 != val1)) {

        overflow = true;

      }

    }

    return overflow;

}

bool OverflowAddINode::can_overflow(const Type* t1, const Type* t2) const {

  return AddHelper<OverflowAddINode>::can_overflow(t1, t2);

}

bool OverflowSubINode::can_overflow(const Type* t1, const Type* t2) const {

  if (in(1) == in(2)) {

    return false;

  }

  return SubHelper<OverflowSubINode>::can_overflow(t1, t2);

}

bool OverflowMulINode::can_overflow(const Type* t1, const Type* t2) const {

  return MulHelper<OverflowMulINode>::can_overflow(t1, t2);

}

bool OverflowAddLNode::can_overflow(const Type* t1, const Type* t2) const {

  return AddHelper<OverflowAddLNode>::can_overflow(t1, t2);

}

bool OverflowSubLNode::can_overflow(const Type* t1, const Type* t2) const {

  if (in(1) == in(2)) {

    return false;

  }

  return SubHelper<OverflowSubLNode>::can_overflow(t1, t2);

}

bool OverflowMulLNode::can_overflow(const Type* t1, const Type* t2) const {

  return MulHelper<OverflowMulLNode>::can_overflow(t1, t2);

}

const Type* OverflowNode::sub(const Type* t1, const Type* t2) const {

  return TypeInt::CC;

}

template <typename OverflowOp>

struct IdealHelper {

  typedef typename OverflowOp::TypeClass TypeClass; // TypeInt, TypeLong

  typedef typename TypeClass::NativeType NativeType;

  static Node* Ideal(const OverflowOp* node, PhaseGVN* phase, bool can_reshape) {

    Node* arg1 = node->in(1);

    Node* arg2 = node->in(2);

    const Type* type1 = phase->type(arg1);

    const Type* type2 = phase->type(arg2);

    if (type1 == NULL || type2 == NULL) {

      return NULL;

    }

    if (type1 != Type::TOP && type1->singleton() &&

        type2 != Type::TOP && type2->singleton()) {

      NativeType val1 = TypeClass::as_self(type1)->get_con();

      NativeType val2 = TypeClass::as_self(type2)->get_con();

      if (node->will_overflow(val1, val2) == false) {

        Node* con_result = ConINode::make(0);

        return con_result;

      }

      return NULL;

    }

    return NULL;

  }

  static const Type* Value(const OverflowOp* node, PhaseTransform* phase) {

    const Type *t1 = phase->type( node->in(1) );

    const Type *t2 = phase->type( node->in(2) );

    if( t1 == Type::TOP ) return Type::TOP;

    if( t2 == Type::TOP ) return Type::TOP;

    const TypeClass* i1 = TypeClass::as_self(t1);

    const TypeClass* i2 = TypeClass::as_self(t2);

    if (i1 == NULL || i2 == NULL) {

      return TypeInt::CC;

    }

    if (t1->singleton() && t2->singleton()) {

      NativeType val1 = i1->get_con();

      NativeType val2 = i2->get_con();

      if (node->will_overflow(val1, val2)) {

        return TypeInt::CC;

      }

      return TypeInt::ZERO;

    } else if (i1 != TypeClass::TYPE_DOMAIN && i2 != TypeClass::TYPE_DOMAIN) {

      if (node->will_overflow(i1->_lo, i2->_lo)) {

        return TypeInt::CC;

      } else if (node->will_overflow(i1->_lo, i2->_hi)) {

        return TypeInt::CC;

      } else if (node->will_overflow(i1->_hi, i2->_lo)) {

        return TypeInt::CC;

      } else if (node->will_overflow(i1->_hi, i2->_hi)) {

        return TypeInt::CC;

      }

      return TypeInt::ZERO;

    }

    if (!node->can_overflow(t1, t2)) {

      return TypeInt::ZERO;

    }

    return TypeInt::CC;

  }

};

Node* OverflowINode::Ideal(PhaseGVN* phase, bool can_reshape) {

  return IdealHelper<OverflowINode>::Ideal(this, phase, can_reshape);

}

Node* OverflowLNode::Ideal(PhaseGVN* phase, bool can_reshape) {

  return IdealHelper<OverflowLNode>::Ideal(this, phase, can_reshape);

}

const Type* OverflowINode::Value(PhaseTransform* phase) const {

  return IdealHelper<OverflowINode>::Value(this, phase);

}

const Type* OverflowLNode::Value(PhaseTransform* phase) const {

  return IdealHelper<OverflowLNode>::Value(this, phase);

}