Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright 1997-2005 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  *

  */

 #include "incls/_precompiled.incl"

 #include "incls/_rootnode.cpp.incl"

 //------------------------------Ideal------------------------------------------

 // Remove dead inputs

 Node *RootNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   for( uint i = 1; i < req(); i++ ) { // For all inputs

     // Check for and remove dead inputs

     if( phase->type(in(i)) == Type::TOP ) {

       del_req(i--);             // Delete TOP inputs

     }

   }

   // I used to do tail-splitting in the Ideal graph here, but it does not

   // work.  The tail-splitting forces values live into the Return to be

   // ready at a point which dominates the split returns.  This forces Stores

   // to be hoisted high.  The "proper" fix would be to split Stores down

   // each path, but this makes the split unprofitable.  If we want to do this

   // optimization, it needs to be done after allocation so we can count all

   // the instructions needing to be cloned in the cost metric.

   // There used to be a spoof here for caffeine marks which completely

   // eliminated very simple self-recursion recursions, but it's not worth it.

   // Deep inlining of self-calls gets nearly all of the same benefits.

   // If we want to get the rest of the win later, we should pattern match

   // simple recursive call trees to closed-form solutions.

   return NULL;                  // No further opportunities exposed

 }

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

 HaltNode::HaltNode( Node *ctrl, Node *frameptr ) : Node(TypeFunc::Parms) {

   Node* top = Compile::current()->top();

   init_req(TypeFunc::Control,  ctrl        );

   init_req(TypeFunc::I_O,      top);

   init_req(TypeFunc::Memory,   top);

   init_req(TypeFunc::FramePtr, frameptr    );

   init_req(TypeFunc::ReturnAdr,top);

 }

 const Type *HaltNode::bottom_type() const { return Type::BOTTOM; }

 //------------------------------Ideal------------------------------------------

 Node *HaltNode::Ideal(PhaseGVN *phase, bool can_reshape) {

   return remove_dead_region(phase, can_reshape) ? this : NULL;

 }

 //------------------------------Value------------------------------------------

 const Type *HaltNode::Value( PhaseTransform *phase ) const {

   return ( phase->type(in(TypeFunc::Control)) == Type::TOP)

     ? Type::TOP

     : Type::BOTTOM;

 }

 const RegMask &HaltNode::out_RegMask() const {

   return RegMask::Empty;

 }