Mercurial > jdk8-mips64-public > hotspot / file comparison
comparison: src/share/vm/opto/rootnode.cpp
src/share/vm/opto/rootnode.cpp
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| 1 /* | |
| 2 * Copyright (c) 1997, 2010, 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 for( uint i = 1; i < req(); i++ ) { // For all inputs | |
| 39 // Check for and remove dead inputs | |
| 40 if( phase->type(in(i)) == Type::TOP ) { | |
| 41 del_req(i--); // Delete TOP inputs | |
| 42 } | |
| 43 } | |
| 44 | |
| 45 // I used to do tail-splitting in the Ideal graph here, but it does not | |
| 46 // work. The tail-splitting forces values live into the Return to be | |
| 47 // ready at a point which dominates the split returns. This forces Stores | |
| 48 // to be hoisted high. The "proper" fix would be to split Stores down | |
| 49 // each path, but this makes the split unprofitable. If we want to do this | |
| 50 // optimization, it needs to be done after allocation so we can count all | |
| 51 // the instructions needing to be cloned in the cost metric. | |
| 52 | |
| 53 // There used to be a spoof here for caffeine marks which completely | |
| 54 // eliminated very simple self-recursion recursions, but it's not worth it. | |
| 55 // Deep inlining of self-calls gets nearly all of the same benefits. | |
| 56 // If we want to get the rest of the win later, we should pattern match | |
| 57 // simple recursive call trees to closed-form solutions. | |
| 58 | |
| 59 return NULL; // No further opportunities exposed | |
| 60 } | |
| 61 | |
| 62 //============================================================================= | |
| 63 HaltNode::HaltNode( Node *ctrl, Node *frameptr ) : Node(TypeFunc::Parms) { | |
| 64 Node* top = Compile::current()->top(); | |
| 65 init_req(TypeFunc::Control, ctrl ); | |
| 66 init_req(TypeFunc::I_O, top); | |
| 67 init_req(TypeFunc::Memory, top); | |
| 68 init_req(TypeFunc::FramePtr, frameptr ); | |
| 69 init_req(TypeFunc::ReturnAdr,top); | |
| 70 } | |
| 71 | |
| 72 const Type *HaltNode::bottom_type() const { return Type::BOTTOM; } | |
| 73 | |
| 74 //------------------------------Ideal------------------------------------------ | |
| 75 Node *HaltNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
| 76 return remove_dead_region(phase, can_reshape) ? this : NULL; | |
| 77 } | |
| 78 | |
| 79 //------------------------------Value------------------------------------------ | |
| 80 const Type *HaltNode::Value( PhaseTransform *phase ) const { | |
| 81 return ( phase->type(in(TypeFunc::Control)) == Type::TOP) | |
| 82 ? Type::TOP | |
| 83 : Type::BOTTOM; | |
| 84 } | |
| 85 | |
| 86 const RegMask &HaltNode::out_RegMask() const { | |
| 87 return RegMask::Empty; | |
| 88 } |
