[Interpreter] Make ForInPrepare take a kRegTriple8 and ForInNext take kRegPair8 for cache state

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index 959e15514976132c32a0292e367ba17ea3b23d5e..c870746f8a59e82be9318c16375cfeff1d7876f3 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -821,10 +821,14 @@ void BytecodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   builder()->CastAccumulatorToJSObject();
   builder()->JumpIfNull(&not_object_label);
   builder()->StoreAccumulatorInRegister(receiver);
-  Register cache_type = register_allocator()->NewRegister();
-  Register cache_array = register_allocator()->NewRegister();
-  Register cache_length = register_allocator()->NewRegister();
-  builder()->ForInPrepare(cache_type, cache_array, cache_length);
+
+  register_allocator()->PrepareForConsecutiveAllocations(3);
+  Register cache_type = register_allocator()->NextConsecutiveRegister();
+  Register cache_array = register_allocator()->NextConsecutiveRegister();
+  Register cache_length = register_allocator()->NextConsecutiveRegister();
+  // Used as kRegTriple8 and kRegPair8 in ForInPrepare and ForInNext.
+  USE(cache_array);
+  builder()->ForInPrepare(cache_type);
 
   // Set up loop counter
   Register index = register_allocator()->NewRegister();
@@ -836,7 +840,8 @@ void BytecodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   loop_builder.Condition();
   builder()->ForInDone(index, cache_length);
   loop_builder.BreakIfTrue();
-  builder()->ForInNext(receiver, cache_type, cache_array, index);
+  DCHECK(Register::AreContiguous(cache_type, cache_array));
+  builder()->ForInNext(receiver, index, cache_type);
   loop_builder.ContinueIfUndefined();
   VisitForInAssignment(stmt->each(), stmt->EachFeedbackSlot());
   Visit(stmt->body());