Fix register hinting for phis.

runtime/vm/flow_graph_allocator.cc

 // Copyright (c) 2013, 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 735 matching lines @@
     //
     //                 g  g'
     //      value    --*
     //
 
     const intptr_t vreg = val->definition()->ssa_temp_index();
     LiveRange* range = GetLiveRange(vreg);
     if (interfere_at_backedge != NULL) interfere_at_backedge->Add(vreg);
 
     range->AddUseInterval(block->start_pos(), pos);
-    range->AddHintedUse(pos, move->src_slot(), move->dest_slot());
+    range->AddHintedUse(
+        pos,
+        move->src_slot(),
+        GetLiveRange(phi->ssa_temp_index())->assigned_location_slot());
 
     move->set_src(Location::PrefersRegister());
     move_idx++;
   }
 
   // Begin backward iteration with the instruction before the parallel
   // move.
   return goto_instr->previous();
 }
 
@@ skipping 2153 matching lines @@
     OS::Print("-- [after ssa allocator] ir [%s] -------------\n",
               function.ToFullyQualifiedCString());
     FlowGraphPrinter printer(flow_graph_, true);
     printer.PrintBlocks();
     OS::Print("----------------------------------------------\n");
   }
 }
 
 
 }  // namespace dart