[compiler] Introduce a simple store-store elimination, disabled by default.

src/compiler/pipeline.cc

Index: src/compiler/pipeline.cc
diff --git a/src/compiler/pipeline.cc b/src/compiler/pipeline.cc
index 11443e71ccbfabb4d831589121cdc5daf6ddbf5b..ba1fbd69cbda6f92a77d1f2cf65870d3a658e81c 100644
--- a/src/compiler/pipeline.cc
+++ b/src/compiler/pipeline.cc
@@ -9,6 +9,7 @@
 
 #include "src/base/adapters.h"
 #include "src/base/platform/elapsed-timer.h"
+#include "src/compiler/all-nodes.h"

[Jarin, 2016/06/23 09:58:28]

You should not need to add that.

[bgeron, 2016/06/23 12:03:05]

Done.

 #include "src/compiler/ast-graph-builder.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/basic-block-instrumentor.h"
@@ -58,6 +59,7 @@
 #include "src/compiler/simplified-lowering.h"
 #include "src/compiler/simplified-operator-reducer.h"
 #include "src/compiler/simplified-operator.h"
+#include "src/compiler/store-store-elimination.h"
 #include "src/compiler/tail-call-optimization.h"
 #include "src/compiler/type-hint-analyzer.h"
 #include "src/compiler/typer.h"
@@ -1031,6 +1033,15 @@ struct EffectControlLinearizationPhase {
   }
 };
 
+struct StoreStoreEliminationPhase {
+  static const char* phase_name() { return "Store-store elimination"; }
+
+  void Run(PipelineData* data, Zone* temp_zone) {
+    StoreStoreElimination store_store_elimination(data->jsgraph(), temp_zone);
+    store_store_elimination.Run();
+  }
+};
+
 struct MemoryOptimizationPhase {
   static const char* phase_name() { return "memory optimization"; }
 
@@ -1474,6 +1485,11 @@ bool PipelineImpl::OptimizeGraph(Linkage* linkage) {
   Run<EffectControlLinearizationPhase>();
   RunPrintAndVerify("Effect and control linearized", true);
 
+  if (FLAG_turbo_store_elimination) {
+    Run<StoreStoreEliminationPhase>();
+    RunPrintAndVerify("Store-store elimination", true);
+  }
+
   Run<BranchEliminationPhase>();
   RunPrintAndVerify("Branch conditions eliminated", true);