jdk

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/*
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 * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 *
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 */
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#include "precompiled.hpp"
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#include "memory/allocation.inline.hpp"
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#include "opto/callnode.hpp"
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#include "opto/cfgnode.hpp"
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#include "opto/phaseX.hpp"
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#include "opto/regmask.hpp"
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#include "opto/rootnode.hpp"
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#include "opto/subnode.hpp"
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#include "opto/type.hpp"
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//------------------------------Ideal------------------------------------------
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// Remove dead inputs
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Node *RootNode::Ideal(PhaseGVN *phase, bool can_reshape) {
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  bool modified = false;
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  for( uint i = 1; i < req(); i++ ) { // For all inputs
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    // Check for and remove dead inputs
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    if( phase->type(in(i)) == Type::TOP ) {
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      del_req(i--);             // Delete TOP inputs
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      modified = true;
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    }
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  }
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  // I used to do tail-splitting in the Ideal graph here, but it does not
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  // work.  The tail-splitting forces values live into the Return to be
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  // ready at a point which dominates the split returns.  This forces Stores
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  // to be hoisted high.  The "proper" fix would be to split Stores down
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  // each path, but this makes the split unprofitable.  If we want to do this
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  // optimization, it needs to be done after allocation so we can count all
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  // the instructions needing to be cloned in the cost metric.
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  // There used to be a spoof here for caffeine marks which completely
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  // eliminated very simple self-recursion recursions, but it's not worth it.
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  // Deep inlining of self-calls gets nearly all of the same benefits.
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  // If we want to get the rest of the win later, we should pattern match
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  // simple recursive call trees to closed-form solutions.
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  return modified ? this : nullptr;
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}
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//=============================================================================
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HaltNode::HaltNode(Node* ctrl, Node* frameptr, const char* halt_reason, bool reachable)
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                        : Node(TypeFunc::Parms), _halt_reason(halt_reason), _reachable(reachable) {
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  init_class_id(Class_Halt);
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  Node* top = Compile::current()->top();
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  init_req(TypeFunc::Control,  ctrl        );
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  init_req(TypeFunc::I_O,      top);
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  init_req(TypeFunc::Memory,   top);
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  init_req(TypeFunc::FramePtr, frameptr    );
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  init_req(TypeFunc::ReturnAdr,top);
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}
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const Type *HaltNode::bottom_type() const { return Type::BOTTOM; }
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uint HaltNode::size_of() const { return sizeof(*this); }
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//------------------------------Ideal------------------------------------------
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Node *HaltNode::Ideal(PhaseGVN *phase, bool can_reshape) {
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  return remove_dead_region(phase, can_reshape) ? this : nullptr;
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}
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//------------------------------Value------------------------------------------
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const Type* HaltNode::Value(PhaseGVN* phase) const {
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  return ( phase->type(in(TypeFunc::Control)) == Type::TOP)
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    ? Type::TOP
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    : Type::BOTTOM;
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}
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const RegMask &HaltNode::out_RegMask() const {
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  return RegMask::Empty;
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}
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