Remove purely informative definitions from the graph.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index ed21567e51b1a8f455fbf4bd0c00771808ce2273..62fa571bbcdcd2e29e687b5d2ffc4604979cbab8 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -4384,7 +4384,12 @@ void HGraph::RestoreActualValues() {
         instruction != NULL;
         instruction = instruction->next()) {
       if (instruction->ActualValue() != instruction) {
-        instruction->ReplaceAllUsesWith(instruction->ActualValue());
+        ASSERT(instruction->IsInformativeDefinition());
+        if (instruction->IsPurelyInformativeDefinition()) {
+          instruction->DeleteAndReplaceWith(instruction->RedefinedOperand());
+        } else {
+          instruction->ReplaceAllUsesWith(instruction->ActualValue());
+        }
       }
     }
   }