Allow splitting at lifetime holes.

runtime/vm/flow_graph_allocator.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_allocator.h"
 
 #include "vm/bit_vector.h"
 #include "vm/intermediate_language.h"
 #include "vm/il_printer.h"
 #include "vm/flow_graph.h"
@@ skipping 1335 matching lines @@
   if (Start() == split_pos) return this;
 
   UseInterval* interval = finger_.first_pending_use_interval();
   if (interval == NULL) {
     finger_.Initialize(this);
     interval = finger_.first_pending_use_interval();
   }
 
   ASSERT(split_pos < End());
 
-  // Corner case. We need to start over to find previous interval.
-  if (interval->start() == split_pos) interval = first_use_interval_;
+  // Corner case. Split position can be inside the lifetime hole or at its

[Florian Schneider, 2012/10/22 13:08:53]

did you mean: inside _a_ lifetime hole?

+  // end. We need to start over to find the previous interval.
+  if (split_pos <= interval->start()) interval = first_use_interval_;
 
   UseInterval* last_before_split = NULL;
   while (interval->end() <= split_pos) {
     last_before_split = interval;
     interval = interval->next();
   }
 
   const bool split_at_start = (interval->start() == split_pos);
 
   UseInterval* first_after_split = interval;
@@ skipping 867 matching lines @@
     OS::Print("-- [after ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
     FlowGraphPrinter printer(flow_graph_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 }
 
 
 }  // namespace dart