/*

 * Copyright (c) 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 "opto/opaquenode.hpp"

#include "opto/phaseX.hpp"

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

// Do not allow value-numbering

uint Opaque1Node::hash() const { return NO_HASH; }

uint Opaque1Node::cmp( const Node &n ) const {

  return (&n == this);          // Always fail except on self

}

//------------------------------Identity---------------------------------------

// If _major_progress, then more loop optimizations follow.  Do NOT remove

// the opaque Node until no more loop ops can happen.  Note the timing of

// _major_progress; it's set in the major loop optimizations THEN comes the

// call to IterGVN and any chance of hitting this code.  Hence there's no

// phase-ordering problem with stripping Opaque1 in IGVN followed by some

// more loop optimizations that require it.

Node *Opaque1Node::Identity( PhaseTransform *phase ) {

  return phase->C->major_progress() ? this : in(1);

}

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

// A node to prevent unwanted optimizations.  Allows constant folding.  Stops

// value-numbering, most Ideal calls or Identity functions.  This Node is

// specifically designed to prevent the pre-increment value of a loop trip

// counter from being live out of the bottom of the loop (hence causing the

// pre- and post-increment values both being live and thus requiring an extra

// temp register and an extra move).  If we "accidentally" optimize through

// this kind of a Node, we'll get slightly pessimal, but correct, code.  Thus

// it's OK to be slightly sloppy on optimizations here.

// Do not allow value-numbering

uint Opaque2Node::hash() const { return NO_HASH; }

uint Opaque2Node::cmp( const Node &n ) const {

  return (&n == this);          // Always fail except on self

}