1 /*
2 * Copyright (c) 1997, 2023, 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 "memory/allocation.inline.hpp"
27 #include "opto/callnode.hpp"
28 #include "opto/cfgnode.hpp"
29 #include "opto/phaseX.hpp"
30 #include "opto/regmask.hpp"
31 #include "opto/rootnode.hpp"
32 #include "opto/subnode.hpp"
33 #include "opto/type.hpp"
34
35 //------------------------------Ideal------------------------------------------
36 // Remove dead inputs
37 Node *RootNode::Ideal(PhaseGVN *phase, bool can_reshape) {
38 bool modified = false;
39 for( uint i = 1; i < req(); i++ ) { // For all inputs
40 // Check for and remove dead inputs
41 if( phase->type(in(i)) == Type::TOP ) {
42 del_req(i--); // Delete TOP inputs
43 modified = true;
44 }
45 }
46
47 // I used to do tail-splitting in the Ideal graph here, but it does not
48 // work. The tail-splitting forces values live into the Return to be
49 // ready at a point which dominates the split returns. This forces Stores
50 // to be hoisted high. The "proper" fix would be to split Stores down
51 // each path, but this makes the split unprofitable. If we want to do this
52 // optimization, it needs to be done after allocation so we can count all
53 // the instructions needing to be cloned in the cost metric.
54
55 // There used to be a spoof here for caffeine marks which completely
56 // eliminated very simple self-recursion recursions, but it's not worth it.
57 // Deep inlining of self-calls gets nearly all of the same benefits.
58 // If we want to get the rest of the win later, we should pattern match
59 // simple recursive call trees to closed-form solutions.
60
61 return modified ? this : nullptr;
62 }
63
64 //=============================================================================
65 HaltNode::HaltNode(Node* ctrl, Node* frameptr, const char* halt_reason, bool reachable)
66 : Node(TypeFunc::Parms), _halt_reason(halt_reason), _reachable(reachable) {
67 init_class_id(Class_Halt);
68 Node* top = Compile::current()->top();
69 init_req(TypeFunc::Control, ctrl );
70 init_req(TypeFunc::I_O, top);
71 init_req(TypeFunc::Memory, top);
72 init_req(TypeFunc::FramePtr, frameptr );
73 init_req(TypeFunc::ReturnAdr,top);
74 }
75
76 const Type *HaltNode::bottom_type() const { return Type::BOTTOM; }
77 uint HaltNode::size_of() const { return sizeof(*this); }
78
79 //------------------------------Ideal------------------------------------------
80 Node *HaltNode::Ideal(PhaseGVN *phase, bool can_reshape) {
81 return remove_dead_region(phase, can_reshape) ? this : nullptr;
82 }
83
84 //------------------------------Value------------------------------------------
85 const Type* HaltNode::Value(PhaseGVN* phase) const {
86 return ( phase->type(in(TypeFunc::Control)) == Type::TOP)
87 ? Type::TOP
88 : Type::BOTTOM;
89 }
90
91 const RegMask &HaltNode::out_RegMask() const {
92 return RegMask::Empty;
93 }