1/*
2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "opto/opaquenode.hpp"
27#include "opto/phaseX.hpp"
28
29//=============================================================================
30// Do not allow value-numbering
31uint Opaque1Node::hash() const { return NO_HASH; }
32uint Opaque1Node::cmp( const Node &n ) const {
33  return (&n == this);          // Always fail except on self
34}
35
36//------------------------------Identity---------------------------------------
37// If _major_progress, then more loop optimizations follow.  Do NOT remove
38// the opaque Node until no more loop ops can happen.  Note the timing of
39// _major_progress; it's set in the major loop optimizations THEN comes the
40// call to IterGVN and any chance of hitting this code.  Hence there's no
41// phase-ordering problem with stripping Opaque1 in IGVN followed by some
42// more loop optimizations that require it.
43Node* Opaque1Node::Identity(PhaseGVN* phase) {
44  return phase->C->major_progress() ? this : in(1);
45}
46
47//=============================================================================
48// A node to prevent unwanted optimizations.  Allows constant folding.  Stops
49// value-numbering, most Ideal calls or Identity functions.  This Node is
50// specifically designed to prevent the pre-increment value of a loop trip
51// counter from being live out of the bottom of the loop (hence causing the
52// pre- and post-increment values both being live and thus requiring an extra
53// temp register and an extra move).  If we "accidentally" optimize through
54// this kind of a Node, we'll get slightly pessimal, but correct, code.  Thus
55// it's OK to be slightly sloppy on optimizations here.
56
57// Do not allow value-numbering
58uint Opaque2Node::hash() const { return NO_HASH; }
59uint Opaque2Node::cmp( const Node &n ) const {
60  return (&n == this);          // Always fail except on self
61}
62
63Node* Opaque4Node::Identity(PhaseGVN* phase) {
64  return phase->C->major_progress() ? this : in(2);
65}
66
67const Type* Opaque4Node::Value(PhaseGVN* phase) const {
68  return phase->type(in(1));
69}
70
71//=============================================================================
72
73uint ProfileBooleanNode::hash() const { return NO_HASH; }
74uint ProfileBooleanNode::cmp( const Node &n ) const {
75  return (&n == this);
76}
77
78Node *ProfileBooleanNode::Ideal(PhaseGVN *phase, bool can_reshape) {
79  if (can_reshape && _delay_removal) {
80    _delay_removal = false;
81    return this;
82  } else {
83    return NULL;
84  }
85}
86
87Node* ProfileBooleanNode::Identity(PhaseGVN* phase) {
88  if (_delay_removal) {
89    return this;
90  } else {
91    assert(_consumed, "profile should be consumed before elimination");
92    return in(1);
93  }
94}
95