Implement local load/store elimination on basic blocks.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 7b623b50877d80d371dd2d2dad35d9e9faa38fe9..4b8fc2b607defc7ee17c9ffc1a992786ddb59e0d 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -43,6 +43,7 @@
 #include "hydrogen-escape-analysis.h"
 #include "hydrogen-infer-representation.h"
 #include "hydrogen-infer-types.h"
+#include "hydrogen-load-elimination.h"
 #include "hydrogen-gvn.h"
 #include "hydrogen-mark-deoptimize.h"
 #include "hydrogen-minus-zero.h"
@@ -2973,6 +2974,8 @@ bool HGraph::Optimize(BailoutReason* bailout_reason) {
 
   if (FLAG_use_escape_analysis) Run<HEscapeAnalysisPhase>();
 
+  if (FLAG_load_elimination) Run<HLoadEliminationPhase>();
+
   CollectPhis();
 
   if (has_osr()) osr()->FinishOsrValues();