/*

 * Copyright (c) 1997, 2010, 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/callnode.hpp"

#include "opto/cfgnode.hpp"

#include "opto/phaseX.hpp"

#include "opto/regmask.hpp"

#include "opto/rootnode.hpp"

#include "opto/subnode.hpp"

#include "opto/type.hpp"

//------------------------------Ideal------------------------------------------

// Remove dead inputs

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

  bool modified = false;

  for( uint i = 1; i < req(); i++ ) { // For all inputs

    // Check for and remove dead inputs

    if( phase->type(in(i)) == Type::TOP ) {

      del_req(i--);             // Delete TOP inputs

      modified = true;

    }

  }

  // I used to do tail-splitting in the Ideal graph here, but it does not

  // work.  The tail-splitting forces values live into the Return to be

  // ready at a point which dominates the split returns.  This forces Stores

  // to be hoisted high.  The "proper" fix would be to split Stores down

  // each path, but this makes the split unprofitable.  If we want to do this

  // optimization, it needs to be done after allocation so we can count all

  // the instructions needing to be cloned in the cost metric.

  // There used to be a spoof here for caffeine marks which completely

  // eliminated very simple self-recursion recursions, but it's not worth it.

  // Deep inlining of self-calls gets nearly all of the same benefits.

  // If we want to get the rest of the win later, we should pattern match

  // simple recursive call trees to closed-form solutions.

  return modified ? this : NULL;

}

//=============================================================================

HaltNode::HaltNode( Node *ctrl, Node *frameptr ) : Node(TypeFunc::Parms) {

  Node* top = Compile::current()->top();

  init_req(TypeFunc::Control,  ctrl        );

  init_req(TypeFunc::I_O,      top);

  init_req(TypeFunc::Memory,   top);

  init_req(TypeFunc::FramePtr, frameptr    );

  init_req(TypeFunc::ReturnAdr,top);

}

const Type *HaltNode::bottom_type() const { return Type::BOTTOM; }

//------------------------------Ideal------------------------------------------

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

  return remove_dead_region(phase, can_reshape) ? this : NULL;

}

//------------------------------Value------------------------------------------

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

  return ( phase->type(in(TypeFunc::Control)) == Type::TOP)

    ? Type::TOP

    : Type::BOTTOM;

}

const RegMask &HaltNode::out_RegMask() const {

  return RegMask::Empty;

}