/*

 * 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"

MathExactNode::MathExactNode(Node* ctrl, Node* in1) : MultiNode(2) {

  init_class_id(Class_MathExact);

  init_req(0, ctrl);

  init_req(1, in1);

}

MathExactNode::MathExactNode(Node* ctrl, Node* in1, Node* in2) : MultiNode(3) {

  init_class_id(Class_MathExact);

  init_req(0, ctrl);

  init_req(1, in1);

  init_req(2, in2);

}

BoolNode* MathExactNode::bool_node() const {

  Node* flags = flags_node();

  BoolNode* boolnode = flags->unique_out()->as_Bool();

  assert(boolnode != NULL, "must have BoolNode");

  return boolnode;

}

IfNode* MathExactNode::if_node() const {

  BoolNode* boolnode = bool_node();

  IfNode* ifnode = boolnode->unique_out()->as_If();

  assert(ifnode != NULL, "must have IfNode");

  return ifnode;

}

Node* MathExactNode::control_node() const {

  IfNode* ifnode = if_node();

  return ifnode->in(0);

}

Node* MathExactNode::non_throwing_branch() const {

  IfNode* ifnode = if_node();

  if (bool_node()->_test._test == BoolTest::overflow) {

    return ifnode->proj_out(0);

  }

  return ifnode->proj_out(1);

}

// If the MathExactNode won't overflow we have to replace the

// FlagsProjNode and ProjNode that is generated by the MathExactNode

Node* MathExactNode::no_overflow(PhaseGVN* phase, Node* new_result) {

  PhaseIterGVN* igvn = phase->is_IterGVN();

  if (igvn) {

    ProjNode* result = result_node();

    ProjNode* flags = flags_node();

    if (result != NULL) {

      igvn->replace_node(result, new_result);

    }

    if (flags != NULL) {

      BoolNode* boolnode = bool_node();

      switch (boolnode->_test._test) {

        case BoolTest::overflow:

          // if the check is for overflow - never taken

          igvn->replace_node(boolnode, phase->intcon(0));

          break;

        case BoolTest::no_overflow:

          // if the check is for no overflow - always taken

          igvn->replace_node(boolnode, phase->intcon(1));

          break;

        default:

          fatal("Unexpected value of BoolTest");

          break;

      }

      flags->del_req(0);

    }

  }

  return new_result;

}

Node* MathExactINode::match(const ProjNode* proj, const Matcher* m) {

  uint ideal_reg = proj->ideal_reg();

  RegMask rm;

  if (proj->_con == result_proj_node) {

    rm = m->mathExactI_result_proj_mask();

  } else {

    assert(proj->_con == flags_proj_node, "must be result or flags");

    assert(ideal_reg == Op_RegFlags, "sanity");

    rm = m->mathExactI_flags_proj_mask();

  }

  return new (m->C) MachProjNode(this, proj->_con, rm, ideal_reg);

}

Node* MathExactLNode::match(const ProjNode* proj, const Matcher* m) {

  uint ideal_reg = proj->ideal_reg();

  RegMask rm;

  if (proj->_con == result_proj_node) {

    rm = m->mathExactL_result_proj_mask();

  } else {

    assert(proj->_con == flags_proj_node, "must be result or flags");

    assert(ideal_reg == Op_RegFlags, "sanity");

    rm = m->mathExactI_flags_proj_mask();

  }

  return new (m->C) MachProjNode(this, proj->_con, rm, ideal_reg);

}

Node* AddExactINode::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();

    jint result = val1 + val2;

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

    if ( (((val1 ^ result) & (val2 ^ result)) >= 0)) {

      Node* con_result = ConINode::make(phase->C, result);

      return no_overflow(phase, con_result);

    }

    return NULL;

  }

  if (type1 == TypeInt::ZERO || type2 == TypeInt::ZERO) { // (Add 0 x) == x

    Node* add_result = new (phase->C) AddINode(arg1, arg2);

    return no_overflow(phase, add_result);

  }

  if (type2->singleton()) {

    return NULL; // no change - keep constant on the right

  }

  if (type1->singleton()) {

    // Make it x + Constant - move constant to the right

    swap_edges(1, 2);

    return this;

  }

  if (arg2->is_Load()) {

    return NULL; // no change - keep load on the right

  }

  if (arg1->is_Load()) {

    // Make it x + Load - move load to the right

    swap_edges(1, 2);

    return this;

  }

  if (arg1->_idx > arg2->_idx) {

    // Sort the edges

    swap_edges(1, 2);

    return this;

  }

  return NULL;

}

Node* AddExactLNode::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();

    jlong result = val1 + val2;

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

    if ( (((val1 ^ result) & (val2 ^ result)) >= 0)) {

      Node* con_result = ConLNode::make(phase->C, result);

      return no_overflow(phase, con_result);

    }

    return NULL;

  }

  if (type1 == TypeLong::ZERO || type2 == TypeLong::ZERO) { // (Add 0 x) == x

    Node* add_result = new (phase->C) AddLNode(arg1, arg2);

    return no_overflow(phase, add_result);

  }

  if (type2->singleton()) {

    return NULL; // no change - keep constant on the right

  }

  if (type1->singleton()) {

    // Make it x + Constant - move constant to the right

    swap_edges(1, 2);

    return this;

  }

  if (arg2->is_Load()) {

    return NULL; // no change - keep load on the right

  }

  if (arg1->is_Load()) {

    // Make it x + Load - move load to the right

    swap_edges(1, 2);

    return this;

  }

  if (arg1->_idx > arg2->_idx) {

    // Sort the edges

    swap_edges(1, 2);

    return this;

  }

  return NULL;

}

Node* SubExactINode::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();

    jint result = val1 - val2;

    // 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 (((val1 ^ val2) & (val1 ^ result)) >= 0) {

      Node* con_result = ConINode::make(phase->C, result);

      return no_overflow(phase, con_result);

    }

    return NULL;

  }

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

    // Sub with zero is the same as add with zero

    Node* add_result = new (phase->C) AddINode(arg1, arg2);

    return no_overflow(phase, add_result);

  }

  return NULL;

}

Node* SubExactLNode::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();

    jlong result = val1 - val2;

    // 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 (((val1 ^ val2) & (val1 ^ result)) >= 0) {

      Node* con_result = ConLNode::make(phase->C, result);

      return no_overflow(phase, con_result);

    }

    return NULL;

  }

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

    // Sub with zero is the same as add with zero

    Node* add_result = new (phase->C) AddLNode(arg1, arg2);

    return no_overflow(phase, add_result);

  }

  return NULL;

}

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

  Node *arg = in(1);

  const Type* type = phase->type(arg);

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

    jint value = arg->get_int();

    if (value != min_jint) {

      Node* neg_result = ConINode::make(phase->C, -value);

      return no_overflow(phase, neg_result);

    }

  }

  return NULL;

}

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

  Node *arg = in(1);

  const Type* type = phase->type(arg);

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

    jlong value = arg->get_long();

    if (value != min_jlong) {

      Node* neg_result = ConLNode::make(phase->C, -value);

      return no_overflow(phase, neg_result);

    }

  }

  return NULL;

}

Node* MulExactINode::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();

    jlong result = (jlong) val1 * (jlong) val2;

    if ((jint) result == result) {

      // no overflow

      Node* mul_result = ConINode::make(phase->C, result);

      return no_overflow(phase, mul_result);

    }

  }

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

    return no_overflow(phase, ConINode::make(phase->C, 0));

  }

  if (type1 == TypeInt::ONE) {

    Node* mul_result = new (phase->C) AddINode(arg2, phase->intcon(0));

    return no_overflow(phase, mul_result);

  }

  if (type2 == TypeInt::ONE) {

    Node* mul_result = new (phase->C) AddINode(arg1, phase->intcon(0));

    return no_overflow(phase, mul_result);

  }

  if (type1 == TypeInt::MINUS_1) {

    return new (phase->C) NegExactINode(NULL, arg2);

  }

  if (type2 == TypeInt::MINUS_1) {

    return new (phase->C) NegExactINode(NULL, arg1);

  }

  return NULL;

}

Node* MulExactLNode::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();

    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;

      }

    }

    if (!overflow) {

      Node* mul_result = ConLNode::make(phase->C, result);

      return no_overflow(phase, mul_result);

    }

  }

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

    return no_overflow(phase, ConLNode::make(phase->C, 0));

  }

  if (type1 == TypeLong::ONE) {

    Node* mul_result = new (phase->C) AddLNode(arg2, phase->longcon(0));

    return no_overflow(phase, mul_result);

  }

  if (type2 == TypeLong::ONE) {

    Node* mul_result = new (phase->C) AddLNode(arg1, phase->longcon(0));

    return no_overflow(phase, mul_result);

  }

  if (type1 == TypeLong::MINUS_1) {

    return new (phase->C) NegExactLNode(NULL, arg2);

  }

  if (type2 == TypeLong::MINUS_1) {

    return new (phase->C) NegExactLNode(NULL, arg1);

  }

  return NULL;

}