/*
 * Copyright (c) 2013, 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"

OverflowNode::OverflowNode(Node* in1) : CmpNode(in1, in1) {
}

OverflowNode::OverflowNode(Node* in1, Node* in2) : CmpNode(in1, in2) {
}

bool OverflowINode::will_overflow(jint v1, jint v2) const {
  ShouldNotReachHere();
  return true;
}

bool OverflowLNode::will_overflow(jlong v1, jlong v2) const {
  ShouldNotReachHere();
  return true;
}

bool OverflowINode::can_overflow(const Type* t1, const Type* t2) const {
  ShouldNotReachHere();
  return true;
}

bool OverflowLNode::can_overflow(const Type* t1, const Type* t2) const {
  ShouldNotReachHere();
  return true;
}

bool OverflowAddINode::will_overflow(jint v1, jint v2) const {
    jint result = v1 + v2;
    // Hacker's Delight 2-12 Overflow if both arguments have the opposite sign of the result
    if ( (((v1 ^ result) & (v2 ^ result)) >= 0)) {
      return false;
    }
    return true;
}

bool OverflowSubINode::will_overflow(jint v1, jint v2) const {
    jint result = v1 - v2;
    // 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 (((v1 ^ v2) & (v1 ^ result)) >= 0) {
      return false;
    }
    return true;
}

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 {
    jlong result = v1 + v2;
    // Hacker's Delight 2-12 Overflow if both arguments have the opposite sign of the result
    if ( (((v1 ^ result) & (v2 ^ result)) >= 0)) {
      return false;
    }
    return true;
}

bool OverflowSubLNode::will_overflow(jlong v1, jlong v2) const {
    jlong result = v1 - v2;
    // 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 (((v1 ^ v2) & (v1 ^ result)) >= 0) {
      return false;
    }
    return true;
}

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;
}

Node* OverflowINode::Ideal(PhaseGVN* phase, bool can_reshape) {
  Node* arg1 = in(1);
  Node* arg2 = in(2);

  const Type* type1 = phase->type(arg1);
  const Type* type2 = phase->type(arg2);

  if (type1 != Type::TOP && type1->singleton() &&
      type2 != Type::TOP && type2->singleton()) {
    jint val1 = arg1->get_int();
    jint val2 = arg2->get_int();
    if (will_overflow(val1, val2) == false) {
      Node* con_result = ConINode::make(phase->C, 0);
      return con_result;
    }
    return NULL;
  }
  return NULL;
}

Node* OverflowLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
  Node* arg1 = in(1);
  Node* arg2 = in(2);

  const Type* type1 = phase->type(arg1);
  const Type* type2 = phase->type(arg2);

  if (type1 != Type::TOP && type1->singleton() &&
      type2 != Type::TOP && type2->singleton()) {
    jlong val1 = arg1->get_long();
    jlong val2 = arg2->get_long();
    if (will_overflow(val1, val2) == false) {
      Node* con_result = ConINode::make(phase->C, 0);
      return con_result;
    }
    return NULL;
  }

  return NULL;
}

const Type* OverflowINode::Value(PhaseTransform* phase) const {
  const Type *t1 = phase->type( in(1) );
  const Type *t2 = phase->type( in(2) );
  if( t1 == Type::TOP ) return Type::TOP;
  if( t2 == Type::TOP ) return Type::TOP;

  const TypeInt *i1 = t1->isa_int();
  const TypeInt *i2 = t2->isa_int();

  if (t1->singleton() && t2->singleton()) {
    if (i1 == NULL || i2 == NULL) {
      return TypeInt::CC;
    }

    jint val1 = i1->get_con();
    jint val2 = i2->get_con();
    if (will_overflow(val1, val2)) {
      return TypeInt::CC;
    }
    return TypeInt::ZERO;
  } else if (i1 != TypeInt::INT && i2 != TypeInt::INT) {
    if (will_overflow(i1->_lo, i2->_lo)) {
      return TypeInt::CC;
    } else if (will_overflow(i1->_lo, i2->_hi)) {
      return TypeInt::CC;
    } else if (will_overflow(i1->_hi, i2->_lo)) {
      return TypeInt::CC;
    } else if (will_overflow(i1->_hi, i2->_hi)) {
      return TypeInt::CC;
    }
    return TypeInt::ZERO;
  }

  if (!can_overflow(t1, t2)) {
    return TypeInt::ZERO;
  }
  return TypeInt::CC;
}

const Type* OverflowLNode::Value(PhaseTransform* phase) const {
  const Type *t1 = phase->type( in(1) );
  const Type *t2 = phase->type( in(2) );
  if( t1 == Type::TOP ) return Type::TOP;
  if( t2 == Type::TOP ) return Type::TOP;

  const TypeLong *i1 = t1->isa_long();
  const TypeLong *i2 = t2->isa_long();

  if (t1->singleton() && t2->singleton()) {
    if (i1 == NULL || i2 == NULL) {
      return TypeInt::CC;
    }

    jlong val1 = i1->get_con();
    jlong val2 = i2->get_con();
    if (will_overflow(val1, val2)) {
      return TypeInt::CC;
    }
    return TypeInt::ZERO;
  } else if (i1 != TypeLong::LONG && i2 != TypeLong::LONG) {
    if (will_overflow(i1->_lo, i2->_lo)) {
      return TypeInt::CC;
    } else if (will_overflow(i1->_lo, i2->_hi)) {
      return TypeInt::CC;
    } else if (will_overflow(i1->_hi, i2->_lo)) {
      return TypeInt::CC;
    } else if (will_overflow(i1->_hi, i2->_hi)) {
      return TypeInt::CC;
    }
    return TypeInt::ZERO;
  }
  if (!can_overflow(t1, t2)) {
    return TypeInt::ZERO;
  }
  return TypeInt::CC;
}

bool OverflowAddINode::can_overflow(const Type* t1, const Type* t2) const {
  if (t1 == TypeInt::ZERO || t2 == TypeInt::ZERO) {
    return false;
  }
  return true;
}

bool OverflowSubINode::can_overflow(const Type* t1, const Type* t2) const {
  if (in(1) == in(2)) {
    return false;
  }

  if (t2 == TypeInt::ZERO) {
    return false;
  }
  return true;
}

bool OverflowMulINode::can_overflow(const Type* t1, const Type* t2) const {
  if (t1 == TypeInt::ZERO || t2 == TypeInt::ZERO) {
    return false;
  } else if (t1 == TypeInt::ONE || t2 == TypeInt::ONE) {
    return false;
  }
  return true;
}

bool OverflowAddLNode::can_overflow(const Type* t1, const Type* t2) const {
  if (t1 == TypeLong::ZERO || t2 == TypeLong::ZERO) {
    return false;
  }
  return true;
}

bool OverflowSubLNode::can_overflow(const Type* t1, const Type* t2) const {
  if (in(1) == in(2)) {
    return false;
  }

  if (t2 == TypeLong::ZERO) {
    return false;
  }
  return true;
}

bool OverflowMulLNode::can_overflow(const Type* t1, const Type* t2) const {
  if (t1 == TypeLong::ZERO || t2 == TypeLong::ZERO) {
    return false;
  } else if (t1 == TypeLong::ONE || t2 == TypeLong::ONE) {
    return false;
  }
  return true;
}

const Type* OverflowINode::sub(const Type* t1, const Type* t2) const {
  ShouldNotReachHere();
  return TypeInt::CC;
}

const Type* OverflowLNode::sub(const Type* t1, const Type* t2) const {
  ShouldNotReachHere();
  return TypeInt::CC;
}