Revert r13409 ("Make the array bounds check elimination phase optional (and set the foundation for …

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 785430a358874ac63cdffb87e8c5c5e973d7b8ed..0c05ff5a013a4a95a5a03c21a3692d62c27f8b9e 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -743,8 +743,7 @@ HInstruction* HGraphBuilder::BuildUncheckedMonomorphicElementAccess(
     HCheckMaps* mapcheck,
     bool is_js_array,
     ElementsKind elements_kind,
-    bool is_store,
-    Representation checked_index_representation) {
+    bool is_store) {
   Zone* zone = this->zone();
   // No GVNFlag is necessary for ElementsKind if there is an explicit dependency
   // on a HElementsTransition instruction. The flag can also be removed if the
@@ -772,8 +771,8 @@ HInstruction* HGraphBuilder::BuildUncheckedMonomorphicElementAccess(
   HInstruction* checked_key = NULL;
   if (IsExternalArrayElementsKind(elements_kind)) {
     length = AddInstruction(new(zone) HFixedArrayBaseLength(elements));
-    checked_key = AddInstruction(new(zone) HBoundsCheck(
-        key, length, ALLOW_SMI_KEY, checked_index_representation));
+    checked_key = AddInstruction(new(zone) HBoundsCheck(key, length,
+                                                        ALLOW_SMI_KEY));
     HLoadExternalArrayPointer* external_elements =
         new(zone) HLoadExternalArrayPointer(elements);
     AddInstruction(external_elements);
@@ -790,8 +789,8 @@ HInstruction* HGraphBuilder::BuildUncheckedMonomorphicElementAccess(
   } else {
     length = AddInstruction(new(zone) HFixedArrayBaseLength(elements));
   }
-  checked_key = AddInstruction(new(zone) HBoundsCheck(
-      key, length, ALLOW_SMI_KEY, checked_index_representation));
+  checked_key = AddInstruction(new(zone) HBoundsCheck(key, length,
+                                                      ALLOW_SMI_KEY));
   return BuildFastElementAccess(elements, checked_key, val, mapcheck,
                                 elements_kind, is_store);
 }
@@ -3504,12 +3503,10 @@ bool HGraph::Optimize(SmartArrayPointer<char>* bailout_reason) {
   HStackCheckEliminator sce(this);
   sce.Process();
 
-  if (FLAG_array_bounds_checks_elimination) EliminateRedundantBoundsChecks();
-  if (FLAG_array_index_dehoisting) DehoistSimpleArrayIndexComputations();
+  EliminateRedundantBoundsChecks();
+  DehoistSimpleArrayIndexComputations();
   if (FLAG_dead_code_elimination) DeadCodeElimination();
 
-  ApplyActualValues();
-
   return true;
 }
 
@@ -3669,7 +3666,7 @@ class BoundsCheckBbData: public ZoneObject {
     }
 
     if (!keep_new_check) {
-      new_check->DeleteAndReplaceWith(new_check->ActualValue());
+      new_check->DeleteAndReplaceWith(NULL);
     }
 
     return true;
@@ -3805,6 +3802,10 @@ void HGraph::EliminateRedundantBoundsChecks(HBasicBlock* bb,
     if (!i->IsBoundsCheck()) continue;
 
     HBoundsCheck* check = HBoundsCheck::cast(i);
+    check->ReplaceAllUsesWith(check->index());
+
+    if (!FLAG_array_bounds_checks_elimination) continue;
+
     int32_t offset;
     BoundsCheckKey* key =
         BoundsCheckKey::Create(zone(), check, &offset);
@@ -3822,7 +3823,7 @@ void HGraph::EliminateRedundantBoundsChecks(HBasicBlock* bb,
                                                    NULL);
       *data_p = bb_data_list;
     } else if (data->OffsetIsCovered(offset)) {
-      check->DeleteAndReplaceWith(check->ActualValue());
+      check->DeleteAndReplaceWith(NULL);
     } else if (data->BasicBlock() != bb ||
                !data->CoverCheck(check, offset)) {
       // If the check is in the current BB we try to modify it by calling
@@ -3919,6 +3920,8 @@ static void DehoistArrayIndex(ArrayInstructionInterface* array_operation) {
 
 
 void HGraph::DehoistSimpleArrayIndexComputations() {
+  if (!FLAG_array_index_dehoisting) return;
+
   HPhase phase("H_Dehoist index computations", this);
   for (int i = 0; i < blocks()->length(); ++i) {
     for (HInstruction* instr = blocks()->at(i)->first();
@@ -3970,30 +3973,6 @@ void HGraph::DeadCodeElimination() {
 }
 
 
-void HGraph::ApplyActualValues() {
-  HPhase phase("H_Apply actual values", this);
-
-  for (int block_index = 0; block_index < blocks()->length(); block_index++) {
-    HBasicBlock* block = blocks()->at(block_index);
-
-#ifdef DEBUG
-    for (int i = 0; i < block->phis()->length(); i++) {
-      HPhi* phi = block->phis()->at(i);
-      ASSERT(phi->ActualValue() == phi);
-    }
-#endif
-
-    for (HInstruction* instruction = block->first();
-        instruction != NULL;
-        instruction = instruction->next()) {
-      if (instruction->ActualValue() != instruction) {
-        instruction->ReplaceAllUsesWith(instruction->ActualValue());
-      }
-    }
-  }
-}
-
-
 void HOptimizedGraphBuilder::AddPhi(HPhi* instr) {
   ASSERT(current_block() != NULL);
   current_block()->AddPhi(instr);