Change the handling of stack check on backward branches

src/x64/lithium-x64.cc

 // Copyright 2011 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 372 matching lines @@
   for (int i = 0; i < graph()->blocks()->length(); ++i) {
     HBasicBlock* block = graph()->blocks()->at(i);
     int first = block->first_instruction_index();
     int last = block->last_instruction_index();
     LInstruction* first_instr = instructions()->at(first);
     LInstruction* last_instr = instructions()->at(last);
 
     LLabel* label = LLabel::cast(first_instr);
     if (last_instr->IsGoto()) {
       LGoto* goto_instr = LGoto::cast(last_instr);
-      if (!goto_instr->include_stack_check() &&
-          label->IsRedundant() &&
+      if (label->IsRedundant() &&
           !label->is_loop_header()) {
         bool can_eliminate = true;
         for (int i = first + 1; i < last && can_eliminate; ++i) {
           LInstruction* cur = instructions()->at(i);
           if (cur->IsGap()) {
             LGap* gap = LGap::cast(cur);
             if (!gap->IsRedundant()) {
               can_eliminate = false;
             }
           } else {
@@ skipping 626 matching lines @@
       op = UseAny(value);
     }
     result->AddValue(op, value->representation());
   }
 
   return result;
 }
 
 
 LInstruction* LChunkBuilder::DoGoto(HGoto* instr) {
-  LGoto* result = new LGoto(instr->FirstSuccessor()->block_id(),
-                            instr->include_stack_check());
-  return (instr->include_stack_check())
-      ? AssignPointerMap(result)
-      : result;
+  return new LGoto(instr->FirstSuccessor()->block_id());
 }
 
 
 LInstruction* LChunkBuilder::DoTest(HTest* instr) {
   HValue* v = instr->value();
   if (!v->EmitAtUses()) return new LBranch(UseRegisterAtStart(v));
   ASSERT(!v->HasSideEffects());
   if (v->IsClassOfTest()) {
     HClassOfTest* compare = HClassOfTest::cast(v);
     ASSERT(compare->value()->representation().IsTagged());
@@ skipping 1146 matching lines @@
         set_deoptimization_environment(result->environment());
     ClearInstructionPendingDeoptimizationEnvironment();
     return result;
   }
 
   return NULL;
 }
 
 
 LInstruction* LChunkBuilder::DoStackCheck(HStackCheck* instr) {
-  return MarkAsCall(new LStackCheck, instr);
+  if (instr->is_function_entry()) {
+    return MarkAsCall(new LStackCheck, instr);
+  } else {
+    ASSERT(instr->is_backwards_branch());
+    return AssignEnvironment(AssignPointerMap(new LStackCheck));
+  }
 }
 
 
 LInstruction* LChunkBuilder::DoEnterInlined(HEnterInlined* instr) {
   HEnvironment* outer = current_block_->last_environment();
   HConstant* undefined = graph()->GetConstantUndefined();
   HEnvironment* inner = outer->CopyForInlining(instr->closure(),
                                                instr->function(),
                                                HEnvironment::LITHIUM,
                                                undefined,
@@ skipping 15 matching lines @@
   LOperand* key = UseOrConstantAtStart(instr->key());
   LOperand* object = UseOrConstantAtStart(instr->object());
   LIn* result = new LIn(key, object);
   return MarkAsCall(DefineFixed(result, rax), instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64