Allow HPhis to have an invalid merge index.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 130 matching lines @@
     ASSERT(last_environment() != NULL);
     ASSERT(!last_environment()->ast_id().IsNone());
     HBlockEntry* entry = new(zone()) HBlockEntry();
     entry->InitializeAsFirst(this);
     first_ = last_ = entry;
   }
   instr->InsertAfter(last_);
 }
 
 
+HPhi* HBasicBlock::AddNewPhi(int merged_index) {
+  if (graph()->IsInsideNoSideEffectsScope()) {
+    merged_index = HPhi::kInvalidMergedIndex;
+  }
+  HPhi* phi = new(zone()) HPhi(merged_index, zone());
+  AddPhi(phi);
+  return phi;
+}
+
+
 HSimulate* HBasicBlock::CreateSimulate(BailoutId ast_id,
                                        RemovableSimulate removable) {
   ASSERT(HasEnvironment());
   HEnvironment* environment = last_environment();
   ASSERT(ast_id.IsNone() ||
          ast_id == BailoutId::StubEntry() ||
          environment->closure()->shared()->VerifyBailoutId(ast_id));
 
   int push_count = environment->push_count();
   int pop_count = environment->pop_count();
@@ skipping 35 matching lines @@
                        FunctionState* state,
                        bool add_simulate) {
   bool drop_extra = state != NULL &&
       state->inlining_kind() == DROP_EXTRA_ON_RETURN;
 
   if (block->IsInlineReturnTarget()) {
     AddInstruction(new(zone()) HLeaveInlined());
     UpdateEnvironment(last_environment()->DiscardInlined(drop_extra));
   }
 
-  if (add_simulate) AddSimulate(BailoutId::None());
+  if (add_simulate) AddNewSimulate(BailoutId::None());
   HGoto* instr = new(zone()) HGoto(block);
   Finish(instr);
 }
 
 
 void HBasicBlock::AddLeaveInlined(HValue* return_value,
                                   FunctionState* state) {
   HBasicBlock* target = state->function_return();
   bool drop_extra = state->inlining_kind() == DROP_EXTRA_ON_RETURN;
 
   ASSERT(target->IsInlineReturnTarget());
   ASSERT(return_value != NULL);
   AddInstruction(new(zone()) HLeaveInlined());
   UpdateEnvironment(last_environment()->DiscardInlined(drop_extra));
   last_environment()->Push(return_value);
-  AddSimulate(BailoutId::None());
+  AddNewSimulate(BailoutId::None());
   HGoto* instr = new(zone()) HGoto(target);
   Finish(instr);
 }
 
 
 void HBasicBlock::SetInitialEnvironment(HEnvironment* env) {
   ASSERT(!HasEnvironment());
   ASSERT(first() == NULL);
   UpdateEnvironment(env);
 }
@@ skipping 664 matching lines @@
   body_block_ = NULL;
   exit_block_ = NULL;
 }
 
 
 HValue* HGraphBuilder::LoopBuilder::BeginBody(
     HValue* initial,
     HValue* terminating,
     Token::Value token) {
   HEnvironment* env = builder_->environment();
-  phi_ = new(zone()) HPhi(env->values()->length(), zone());
-  header_block_->AddPhi(phi_);
+  phi_ = header_block_->AddNewPhi(env->values()->length());
   phi_->AddInput(initial);
   env->Push(initial);
   builder_->current_block()->GotoNoSimulate(header_block_);
 
   HEnvironment* body_env = env->Copy();
   HEnvironment* exit_env = env->Copy();
   body_block_ = builder_->CreateBasicBlock(body_env);
   exit_block_ = builder_->CreateBasicBlock(exit_env);
   // Remove the phi from the expression stack
   body_env->Pop();
@@ skipping 56 matching lines @@
   set_current_block(graph()->entry_block());
   if (!BuildGraph()) return NULL;
   graph()->FinalizeUniqueValueIds();
   return graph_;
 }
 
 
 HInstruction* HGraphBuilder::AddInstruction(HInstruction* instr) {
   ASSERT(current_block() != NULL);
   current_block()->AddInstruction(instr);
-  if (no_side_effects_scope_count_ > 0) {
+  if (graph()->IsInsideNoSideEffectsScope()) {
     instr->SetFlag(HValue::kHasNoObservableSideEffects);
   }
   return instr;
 }
 
 
 void HGraphBuilder::AddIncrementCounter(StatsCounter* counter,
                                         HValue* context) {
   if (FLAG_native_code_counters && counter->Enabled()) {
     HValue* reference = Add<HConstant>(ExternalReference(counter));
     HValue* old_value = Add<HLoadNamedField>(reference,
                                              HObjectAccess::ForCounter());
     HValue* new_value = Add<HAdd>(old_value, graph()->GetConstant1());
     new_value->ClearFlag(HValue::kCanOverflow);  // Ignore counter overflow
     Add<HStoreNamedField>(reference, HObjectAccess::ForCounter(),
                           new_value);
   }
 }
 
 
 void HGraphBuilder::AddSimulate(BailoutId id,
                                 RemovableSimulate removable) {
   ASSERT(current_block() != NULL);
-  ASSERT(no_side_effects_scope_count_ == 0);
-  current_block()->AddSimulate(id, removable);
+  ASSERT(!graph()->IsInsideNoSideEffectsScope());
+  current_block()->AddNewSimulate(id, removable);
 }
 
 
 HBasicBlock* HGraphBuilder::CreateBasicBlock(HEnvironment* env) {
   HBasicBlock* b = graph()->CreateBasicBlock();
   b->SetInitialEnvironment(env);
   return b;
 }
 
 
 HBasicBlock* HGraphBuilder::CreateLoopHeaderBlock() {
   HBasicBlock* header = graph()->CreateBasicBlock();
   HEnvironment* entry_env = environment()->CopyAsLoopHeader(header);
   header->SetInitialEnvironment(entry_env);
   header->AttachLoopInformation();
   return header;
 }
 
 
 HValue* HGraphBuilder::BuildCheckHeapObject(HValue* obj) {
   if (obj->type().IsHeapObject()) return obj;
   return Add<HCheckHeapObject>(obj);
 }
 
 
 void HGraphBuilder::FinishExitWithHardDeoptimization(
     HBasicBlock* continuation) {
   PadEnvironmentForContinuation(current_block(), continuation);
   Add<HDeoptimize>(Deoptimizer::EAGER);
-  if (no_side_effects_scope_count_ > 0) {
+  if (graph()->IsInsideNoSideEffectsScope()) {
     current_block()->GotoNoSimulate(continuation);
   } else {
     current_block()->Goto(continuation);
   }
 }
 
 
 void HGraphBuilder::PadEnvironmentForContinuation(
     HBasicBlock* from,
     HBasicBlock* continuation) {
@@ skipping 991 matching lines @@
       phi_list_(NULL),
       uint32_instructions_(NULL),
       osr_(NULL),
       info_(info),
       zone_(info->zone()),
       is_recursive_(false),
       use_optimistic_licm_(false),
       has_soft_deoptimize_(false),
       depends_on_empty_array_proto_elements_(false),
       type_change_checksum_(0),
-      maximum_environment_size_(0) {
+      maximum_environment_size_(0),
+      no_side_effects_scope_count_(0) {
   if (info->IsStub()) {
     HydrogenCodeStub* stub = info->code_stub();
     CodeStubInterfaceDescriptor* descriptor =
         stub->GetInterfaceDescriptor(isolate_);
     start_environment_ =
         new(zone_) HEnvironment(zone_, descriptor->environment_length());
   } else {
     start_environment_ =
         new(zone_) HEnvironment(NULL, info->scope(), info->closure(), zone_);
   }
@@ skipping 7145 matching lines @@
   ASSERT(!block->IsLoopHeader());
   ASSERT(values_.length() == other->values_.length());
 
   int length = values_.length();
   for (int i = 0; i < length; ++i) {
     HValue* value = values_[i];
     if (value != NULL && value->IsPhi() && value->block() == block) {
       // There is already a phi for the i'th value.
       HPhi* phi = HPhi::cast(value);
       // Assert index is correct and that we haven't missed an incoming edge.
-      ASSERT(phi->merged_index() == i);
+      ASSERT(phi->merged_index() == i || !phi->HasMergedIndex());
       ASSERT(phi->OperandCount() == block->predecessors()->length());
       phi->AddInput(other->values_[i]);
     } else if (values_[i] != other->values_[i]) {
       // There is a fresh value on the incoming edge, a phi is needed.
       ASSERT(values_[i] != NULL && other->values_[i] != NULL);
-      HPhi* phi = new(zone()) HPhi(i, zone());
+      HPhi* phi = block->AddNewPhi(i);
       HValue* old_value = values_[i];
       for (int j = 0; j < block->predecessors()->length(); j++) {
         phi->AddInput(old_value);
       }
       phi->AddInput(other->values_[i]);
       this->values_[i] = phi;
-      block->AddPhi(phi);
     }
   }
 }
 
 
 void HEnvironment::Bind(int index, HValue* value) {
   ASSERT(value != NULL);
   assigned_variables_.Add(index, zone());
   values_[index] = value;
 }
@@ skipping 40 matching lines @@
 HEnvironment* HEnvironment::CopyWithoutHistory() const {
   HEnvironment* result = Copy();
   result->ClearHistory();
   return result;
 }
 
 
 HEnvironment* HEnvironment::CopyAsLoopHeader(HBasicBlock* loop_header) const {
   HEnvironment* new_env = Copy();
   for (int i = 0; i < values_.length(); ++i) {
-    HPhi* phi = new(zone()) HPhi(i, zone());
+    HPhi* phi = loop_header->AddNewPhi(i);
     phi->AddInput(values_[i]);
     new_env->values_[i] = phi;
-    loop_header->AddPhi(phi);
   }
   new_env->ClearHistory();
   return new_env;
 }
 
 
 HEnvironment* HEnvironment::CreateStubEnvironment(HEnvironment* outer,
                                                   Handle<JSFunction> target,
                                                   FrameType frame_type,
                                                   int arguments) const {
@@ skipping 401 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal