[crankshaft] Reland "Only exclude explicit 'arguments' (and 'this') from liveness analysis."

src/crankshaft/hydrogen.h

Index: src/crankshaft/hydrogen.h
diff --git a/src/crankshaft/hydrogen.h b/src/crankshaft/hydrogen.h
index 7d49b06fed3884c8988e176e4e36f3b00b34b53e..55bca719e48c7f532cd98f383554bf57e65fb891 100644
--- a/src/crankshaft/hydrogen.h
+++ b/src/crankshaft/hydrogen.h
@@ -2362,21 +2362,19 @@ class HOptimizedGraphBuilder : public HGraphBuilder, public AstVisitor {
   void Bind(Variable* var, HValue* value) { environment()->Bind(var, value); }
   bool IsEligibleForEnvironmentLivenessAnalysis(Variable* var,
                                                 int index,
-                                                HValue* value,
                                                 HEnvironment* env) {
     if (!FLAG_analyze_environment_liveness) return false;
     // |this| and |arguments| are always live; zapping parameters isn't
     // safe because function.arguments can inspect them at any time.
     return !var->is_this() &&
            !var->is_arguments() &&
-           !value->IsArgumentsObject() &&
            env->is_local_index(index);
   }
   void BindIfLive(Variable* var, HValue* value) {
     HEnvironment* env = environment();
     int index = env->IndexFor(var);
     env->Bind(index, value);
-    if (IsEligibleForEnvironmentLivenessAnalysis(var, index, value, env)) {
+    if (IsEligibleForEnvironmentLivenessAnalysis(var, index, env)) {
       HEnvironmentMarker* bind =
           Add<HEnvironmentMarker>(HEnvironmentMarker::BIND, index);
       USE(bind);
@@ -2388,8 +2386,7 @@ class HOptimizedGraphBuilder : public HGraphBuilder, public AstVisitor {
   HValue* LookupAndMakeLive(Variable* var) {
     HEnvironment* env = environment();
     int index = env->IndexFor(var);
-    HValue* value = env->Lookup(index);
-    if (IsEligibleForEnvironmentLivenessAnalysis(var, index, value, env)) {
+    if (IsEligibleForEnvironmentLivenessAnalysis(var, index, env)) {
       HEnvironmentMarker* lookup =
           Add<HEnvironmentMarker>(HEnvironmentMarker::LOOKUP, index);
       USE(lookup);
@@ -2397,7 +2394,7 @@ class HOptimizedGraphBuilder : public HGraphBuilder, public AstVisitor {
       lookup->set_closure(env->closure());
 #endif
     }
-    return value;
+    return env->Lookup(index);
   }
 
   // The value of the arguments object is allowed in some but not most value