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src/hotspot/share/opto/split_if.cpp

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  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/loopnode.hpp"
 29 #include "opto/movenode.hpp"
 30 #include "opto/opaquenode.hpp"
 31 
 32 
 33 //------------------------------split_thru_region------------------------------
 34 // Split Node 'n' through merge point.
 35 RegionNode* PhaseIdealLoop::split_thru_region(Node* n, RegionNode* region) {
 36   assert(n->is_CFG(), "");
 37   RegionNode* r = new RegionNode(region->req());
 38   IdealLoopTree* loop = get_loop(n);
 39   for (uint i = 1; i < region->req(); i++) {
 40     Node* x = n->clone();
 41     Node* in0 = n->in(0);
 42     if (in0->in(0) == region) x->set_req(0, in0->in(i));
 43     for (uint j = 1; j < n->req(); j++) {
 44       Node* in = n->in(j);
 45       if (get_ctrl(in) == region) {
 46         x->set_req(j, in->in(i));
 47       }

495       Node* n = region->out(i);
496       if( n == region ) continue;
497       // The IF to be split is OK.
498       if( n == iff ) continue;
499       if( !n->is_Phi() ) {      // Found pinned memory op or such
500         if (split_up(n, region, iff)) {
501           i = region->refresh_out_pos(i);
502           progress = true;
503         }
504         continue;
505       }
506       assert( n->in(0) == region, "" );
507 
508       // Recursively split up all users of a Phi
509       for (j = n->outs(); n->has_out(j); j++) {
510         Node* m = n->out(j);
511         // If m is dead, throw it away, and declare progress
512         if (_nodes[m->_idx] == NULL) {
513           _igvn.remove_dead_node(m);
514           // fall through
515         }
516         else if (m != iff && split_up(m, region, iff)) {
517           // fall through
518         } else {
519           continue;
520         }
521         // Something unpredictable changed.
522         // Tell the iterators to refresh themselves, and rerun the loop.
523         i = region->refresh_out_pos(i);
524         j = region->refresh_out_pos(j);
525         progress = true;
526       }
527     }
528   }
529 
530   // Now we have no instructions in the block containing the IF.
531   // Split the IF.
532   RegionNode *new_iff = split_thru_region(iff, region);
533 
534   // Replace both uses of 'new_iff' with Regions merging True/False
535   // paths.  This makes 'new_iff' go dead.
536   Node *old_false = NULL, *old_true = NULL;

  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/inlinetypenode.hpp"
 29 #include "opto/loopnode.hpp"
 30 #include "opto/movenode.hpp"
 31 #include "opto/opaquenode.hpp"
 32 
 33 
 34 //------------------------------split_thru_region------------------------------
 35 // Split Node 'n' through merge point.
 36 RegionNode* PhaseIdealLoop::split_thru_region(Node* n, RegionNode* region) {
 37   assert(n->is_CFG(), "");
 38   RegionNode* r = new RegionNode(region->req());
 39   IdealLoopTree* loop = get_loop(n);
 40   for (uint i = 1; i < region->req(); i++) {
 41     Node* x = n->clone();
 42     Node* in0 = n->in(0);
 43     if (in0->in(0) == region) x->set_req(0, in0->in(i));
 44     for (uint j = 1; j < n->req(); j++) {
 45       Node* in = n->in(j);
 46       if (get_ctrl(in) == region) {
 47         x->set_req(j, in->in(i));
 48       }

496       Node* n = region->out(i);
497       if( n == region ) continue;
498       // The IF to be split is OK.
499       if( n == iff ) continue;
500       if( !n->is_Phi() ) {      // Found pinned memory op or such
501         if (split_up(n, region, iff)) {
502           i = region->refresh_out_pos(i);
503           progress = true;
504         }
505         continue;
506       }
507       assert( n->in(0) == region, "" );
508 
509       // Recursively split up all users of a Phi
510       for (j = n->outs(); n->has_out(j); j++) {
511         Node* m = n->out(j);
512         // If m is dead, throw it away, and declare progress
513         if (_nodes[m->_idx] == NULL) {
514           _igvn.remove_dead_node(m);
515           // fall through
516         } else if (m != iff && split_up(m, region, iff)) {

517           // fall through
518         } else {
519           continue;
520         }
521         // Something unpredictable changed.
522         // Tell the iterators to refresh themselves, and rerun the loop.
523         i = region->refresh_out_pos(i);
524         j = region->refresh_out_pos(j);
525         progress = true;
526       }
527     }
528   }
529 
530   // Now we have no instructions in the block containing the IF.
531   // Split the IF.
532   RegionNode *new_iff = split_thru_region(iff, region);
533 
534   // Replace both uses of 'new_iff' with Regions merging True/False
535   // paths.  This makes 'new_iff' go dead.
536   Node *old_false = NULL, *old_true = NULL;
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