Fix crash during parallel moves.

runtime/vm/flow_graph_compiler_x64.cc

Index: runtime/vm/flow_graph_compiler_x64.cc
===================================================================
--- runtime/vm/flow_graph_compiler_x64.cc	(revision 9788)
+++ runtime/vm/flow_graph_compiler_x64.cc	(working copy)
@@ -45,7 +45,7 @@
     const GrowableArray<Location>* locations = deoptimization_env_->locations();
 
     for (intptr_t i = 0; i < values.length(); i++) {
-      Location loc = (*locations)[i];
+      const Location loc = (*locations)[i];
       if (loc.IsInvalid()) {
         ASSERT(values[i]->IsConstant());
         __ PushObject(values[i]->AsConstant()->value());
@@ -1113,8 +1113,9 @@
 
 
 void ParallelMoveResolver::EmitMove(int index) {
-  Location source = moves_[index].src();
-  Location destination = moves_[index].dest();
+  MoveOperands* move = moves_[index];
+  const Location source = move->src();
+  const Location destination = move->dest();
 
   ASSERT(destination.IsRegister());
   if (source.IsRegister()) {
@@ -1123,30 +1124,31 @@
     ASSERT(source.IsConstant());
     __ LoadObject(destination.reg(), source.constant());
   }
-  moves_[index].Eliminate();
+  move->Eliminate();
 }
 
 
 void ParallelMoveResolver::EmitSwap(int index) {
-  Location source = moves_[index].src();
-  Location destination = moves_[index].dest();
+  MoveOperands* move = moves_[index];
+  const Location source = move->src();
+  const Location destination = move->dest();
 
   ASSERT(source.IsRegister() && destination.IsRegister());
   __ xchgq(destination.reg(), source.reg());
 
   // The swap of source and destination has executed a move from source to
   // destination.
-  moves_[index].Eliminate();
+  move->Eliminate();
 
   // Any unperformed (including pending) move with a source of either
   // this move's source or destination needs to have their source
   // changed to reflect the state of affairs after the swap.
   for (int i = 0; i < moves_.length(); ++i) {
-    MoveOperands other_move = moves_[i];
+    const MoveOperands& other_move = *moves_[i];
     if (other_move.Blocks(source)) {
-      moves_[i].set_src(destination);
+      moves_[i]->set_src(destination);
     } else if (other_move.Blocks(destination)) {
-      moves_[i].set_src(source);
+      moves_[i]->set_src(source);
     }
   }
 }