src/share/vm/opto/reg_split.cpp
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src/share/vm/opto/reg_split.cpp

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   1 /*
   2  * Copyright (c) 2000, 2013, 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 "libadt/vectset.hpp"
  27 #include "memory/allocation.inline.hpp"

  28 #include "opto/addnode.hpp"
  29 #include "opto/c2compiler.hpp"
  30 #include "opto/callnode.hpp"
  31 #include "opto/cfgnode.hpp"
  32 #include "opto/chaitin.hpp"
  33 #include "opto/loopnode.hpp"
  34 #include "opto/machnode.hpp"
  35 
  36 //------------------------------Split--------------------------------------
  37 // Walk the graph in RPO and for each lrg which spills, propagate reaching
  38 // definitions.  During propagation, split the live range around regions of
  39 // High Register Pressure (HRP).  If a Def is in a region of Low Register
  40 // Pressure (LRP), it will not get spilled until we encounter a region of
  41 // HRP between it and one of its uses.  We will spill at the transition
  42 // point between LRP and HRP.  Uses in the HRP region will use the spilled
  43 // Def.  The first Use outside the HRP region will generate a SpillCopy to
  44 // hoist the live range back up into a register, and all subsequent uses
  45 // will use that new Def until another HRP region is encountered.  Defs in
  46 // HRP regions will get trailing SpillCopies to push the LRG down into the
  47 // stack immediately.


   1 /*
   2  * Copyright (c) 2000, 2016, 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 "libadt/vectset.hpp"
  27 #include "memory/allocation.inline.hpp"
  28 #include "memory/resourceArea.hpp"
  29 #include "opto/addnode.hpp"
  30 #include "opto/c2compiler.hpp"
  31 #include "opto/callnode.hpp"
  32 #include "opto/cfgnode.hpp"
  33 #include "opto/chaitin.hpp"
  34 #include "opto/loopnode.hpp"
  35 #include "opto/machnode.hpp"
  36 
  37 //------------------------------Split--------------------------------------
  38 // Walk the graph in RPO and for each lrg which spills, propagate reaching
  39 // definitions.  During propagation, split the live range around regions of
  40 // High Register Pressure (HRP).  If a Def is in a region of Low Register
  41 // Pressure (LRP), it will not get spilled until we encounter a region of
  42 // HRP between it and one of its uses.  We will spill at the transition
  43 // point between LRP and HRP.  Uses in the HRP region will use the spilled
  44 // Def.  The first Use outside the HRP region will generate a SpillCopy to
  45 // hoist the live range back up into a register, and all subsequent uses
  46 // will use that new Def until another HRP region is encountered.  Defs in
  47 // HRP regions will get trailing SpillCopies to push the LRG down into the
  48 // stack immediately.


src/share/vm/opto/reg_split.cpp
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