Fix crash during parallel moves.

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_builder.h"
@@ skipping 407 matching lines @@
         ASSERT(pred_idx < join->PredecessorCount());
 
         // Record the corresponding phi input use for each phi.
         ZoneGrowableArray<PhiInstr*>* phis = join->phis();
         intptr_t move_idx = 0;
         for (intptr_t phi_idx = 0; phi_idx < phis->length(); phi_idx++) {
           PhiInstr* phi = (*phis)[phi_idx];
           if (phi == NULL) continue;
 
           Value* val = phi->InputAt(pred_idx);
-          MoveOperands move = parallel_move->moves()[move_idx];
+          MoveOperands* move = parallel_move->MoveOperandsAt(move_idx);
           if (val->IsUse()) {
             const intptr_t virtual_register =
                 val->AsUse()->definition()->ssa_temp_index();
-            Location* slot = move.src_slot();
-            *slot = Location::RequiresRegister();
-            GetLiveRange(virtual_register)->head()->AddUse(NULL, pos, slot);
+            move->set_src(Location::RequiresRegister());
+            GetLiveRange(
+                virtual_register)->head()->AddUse(NULL, pos, move->src_slot());
           } else {
             ASSERT(val->IsConstant());
-            move.set_src(Location::Constant(val->AsConstant()->value()));
+            move->set_src(Location::Constant(val->AsConstant()->value()));
           }
           move_idx++;
         }
 
         // Begin backward iteration with the instruction before the parallel
         // move.
         current = current->previous();
       }
     }
 
@@ skipping 100 matching lines @@
           ASSERT(virtual_register != -1);
 
           LiveRange* range = GetLiveRange(virtual_register);
           range->DefineAt(NULL, pos, NULL);
           UseInterval* interval = GetLiveRange(virtual_register)->head();
 
           for (intptr_t k = 0; k < phi->InputCount(); k++) {
             BlockEntryInstr* pred = block->PredecessorAt(k);
             ASSERT(pred->last_instruction()->IsGoto());
             Instruction* move_instr = pred->last_instruction()->previous();
-            ASSERT(move_instr->IsParallelMove());
+            ParallelMoveInstr* pmove = move_instr->AsParallelMove();
+            ASSERT(pmove != NULL);
 
-            Location* slot =
-                move_instr->AsParallelMove()->moves()[move_idx].dest_slot();
-            *slot = Location::RequiresRegister();
-            interval->AddUse(NULL, pos, slot);
+            MoveOperands* move_operands = pmove->MoveOperandsAt(move_idx);
+            move_operands->set_dest(Location::RequiresRegister());
+            interval->AddUse(NULL, pos, move_operands->dest_slot());
           }
 
           // All phi resolution moves are connected. Phi's live range is
           // complete.
           AddToUnallocated(interval);
 
           move_idx++;
         }
       }
     }
@@ skipping 376 matching lines @@
 
   if (FLAG_trace_ssa_allocator) {
     OS::Print("-- ir after allocation -------------------------\n");
     FlowGraphPrinter printer(Function::Handle(), block_order_, true);
     printer.PrintBlocks();
   }
 }
 
 
 }  // namespace dart