Improvements in positions handling in optimizing compiler.

src/hydrogen-representation-changes.cc

Index: src/hydrogen-representation-changes.cc
diff --git a/src/hydrogen-representation-changes.cc b/src/hydrogen-representation-changes.cc
index d0c9b58258b591b6ba9be80fb2619e6ad0562813..07fc8be38c0437951b05ea4210db9e5b196f1d0a 100644
--- a/src/hydrogen-representation-changes.cc
+++ b/src/hydrogen-representation-changes.cc
@@ -61,8 +61,8 @@ void HRepresentationChangesPhase::InsertRepresentationChangeForUse(
   if (new_value == NULL) {
     new_value = new(graph()->zone()) HChange(
         value, to, is_truncating_to_smi, is_truncating_to_int);
-    if (use_value->position() != RelocInfo::kNoPosition) {
-      new_value->set_position(use_value->position());
+    if (use_value->operand_position(use_index) != RelocInfo::kNoPosition) {
+      new_value->set_position(use_value->operand_position(use_index));
     } else {
       ASSERT(!FLAG_emit_opt_code_positions || !graph()->info()->IsOptimizing());
     }