Use untagged int32 values in evaluation of side-effect free expressions.

src/ia32/virtual-frame-ia32.h

 // Copyright 2009 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 224 matching lines @@
     ASSERT(0 <= index);
     ASSERT(index < local_count());
     return Operand(ebp, kLocal0Offset - index * kPointerSize);
   }
 
   // Push a copy of the value of a local frame slot on top of the frame.
   void PushLocalAt(int index) {
     PushFrameSlotAt(local0_index() + index);
   }
 
+  // Push a copy of the value of a local frame slot on top of the frame.
+  void UntaggedPushLocalAt(int index) {
+    UntaggedPushFrameSlotAt(local0_index() + index);
+  }
+
   // Push the value of a local frame slot on top of the frame and invalidate
   // the local slot.  The slot should be written to before trying to read
   // from it again.
   void TakeLocalAt(int index) {
     TakeFrameSlotAt(local0_index() + index);
   }
 
   // Store the top value on the virtual frame into a local frame slot.  The
   // value is left in place on top of the frame.
   void StoreToLocalAt(int index) {
@@ skipping 20 matching lines @@
     ASSERT(-1 <= index);  // -1 is the receiver.
     ASSERT(index < parameter_count());
     return Operand(ebp, (1 + parameter_count() - index) * kPointerSize);
   }
 
   // Push a copy of the value of a parameter frame slot on top of the frame.
   void PushParameterAt(int index) {
     PushFrameSlotAt(param0_index() + index);
   }
 
+  // Push a copy of the value of a parameter frame slot on top of the frame.
+  void UntaggedPushParameterAt(int index) {
+    UntaggedPushFrameSlotAt(param0_index() + index);
+  }
+
   // Push the value of a paramter frame slot on top of the frame and
   // invalidate the parameter slot.  The slot should be written to before
   // trying to read from it again.
   void TakeParameterAt(int index) {
     TakeFrameSlotAt(param0_index() + index);
   }
 
   // Store the top value on the virtual frame into a parameter frame slot.
   // The value is left in place on top of the frame.
   void StoreToParameterAt(int index) {
@@ skipping 97 matching lines @@
   void EmitPush(Operand operand,
                 NumberInfo info = NumberInfo::Unknown());
   void EmitPush(Immediate immediate,
                 NumberInfo info = NumberInfo::Unknown());
 
   // Push an element on the virtual frame.
   inline void Push(Register reg, NumberInfo info = NumberInfo::Unknown());
   inline void Push(Handle<Object> value);
   inline void Push(Smi* value);
 
+  void PushUntaggedElement(Handle<Object> value);
+
   // Pushing a result invalidates it (its contents become owned by the
   // frame).
   void Push(Result* result) {
     // This assert will trigger if you try to push the same value twice.
     ASSERT(result->is_valid());
     if (result->is_register()) {
       Push(result->reg(), result->number_info());
     } else {
       ASSERT(result->is_constant());
       Push(result->handle());
     }
+    if (cgen()->in_safe_int32_mode()) {
+      ASSERT(result->is_untagged_int32());
+      elements_[element_count() - 1].set_untagged_int32(true);
+    }
     result->Unuse();
   }
 
   // Pushing an expression expects that the expression is trivial (according
   // to Expression::IsTrivial).
   void Push(Expression* expr);
 
   // Nip removes zero or more elements from immediately below the top
   // of the frame, leaving the previous top-of-frame value on top of
   // the frame.  Nip(k) is equivalent to x = Pop(), Drop(k), Push(x).
   inline void Nip(int num_dropped);
 
+  // Check that the frame has no elements containing untagged int32 elements.
+  bool HasNoUntaggedInt32Elements() {
+    for (int i = 0; i < element_count(); ++i) {
+      if (elements_[i].is_untagged_int32()) return false;
+    }
+    return true;
+  }
+
   // Update the type information of a local variable frame element directly.
   inline void SetTypeForLocalAt(int index, NumberInfo info);
 
  private:
   static const int kLocal0Offset = JavaScriptFrameConstants::kLocal0Offset;
   static const int kFunctionOffset = JavaScriptFrameConstants::kFunctionOffset;
   static const int kContextOffset = StandardFrameConstants::kContextOffset;
 
   static const int kHandlerSize = StackHandlerConstants::kSize / kPointerSize;
   static const int kPreallocatedElements = 5 + 8;  // 8 expression stack slots.
@@ skipping 91 matching lines @@
   // Sync a single unsynced element that lies beneath or at the stack pointer.
   void SyncElementBelowStackPointer(int index);
 
   // Sync a single unsynced element that lies just above the stack pointer.
   void SyncElementByPushing(int index);
 
   // Push a copy of a frame slot (typically a local or parameter) on top of
   // the frame.
   inline void PushFrameSlotAt(int index);
 
+  // Push a copy of a frame slot (typically a local or parameter) on top of
+  // the frame, at an untagged int32 value.  Bails out if the value is not
+  // an int32.
+  void UntaggedPushFrameSlotAt(int index);
+
   // Push a the value of a frame slot (typically a local or parameter) on
   // top of the frame and invalidate the slot.
   void TakeFrameSlotAt(int index);
 
   // Store the value on top of the frame to a frame slot (typically a local
   // or parameter).
   void StoreToFrameSlotAt(int index);
 
   // Spill all elements in registers. Spill the top spilled_args elements
   // on the frame.  Sync all other frame elements.
@@ skipping 47 matching lines @@
   inline bool Equals(VirtualFrame* other);
 
   // Classes that need raw access to the elements_ array.
   friend class DeferredCode;
   friend class JumpTarget;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_VIRTUAL_FRAME_IA32_H_