Provide tagged allocation top pointer

src/code-stub-assembler.cc

Index: src/code-stub-assembler.cc
diff --git a/src/code-stub-assembler.cc b/src/code-stub-assembler.cc
index e0963145ff0198c2698e63a55e6f59097eba8623..dc7cf75d7077dad9a310ed3ab25a1c21485a8903 100644
--- a/src/code-stub-assembler.cc
+++ b/src/code-stub-assembler.cc
@@ -351,8 +351,6 @@ Node* CodeStubAssembler::AllocateRawUnaligned(Node* size_in_bytes,
   Node* no_runtime_result = top;
   StoreNoWriteBarrier(MachineType::PointerRepresentation(), top_address,
                       new_top);
-  no_runtime_result = BitcastWordToTagged(
-      IntPtrAdd(no_runtime_result, IntPtrConstant(kHeapObjectTag)));
   result.Bind(no_runtime_result);
   Goto(&merge_runtime);
 
@@ -371,8 +369,8 @@ Node* CodeStubAssembler::AllocateRawAligned(Node* size_in_bytes,
   if (flags & kDoubleAlignment) {
     // TODO(epertoso): Simd128 alignment.
     Label aligned(this), not_aligned(this), merge(this, &adjusted_size);
-    Branch(WordAnd(top, IntPtrConstant(kDoubleAlignmentMask)), &not_aligned,
-           &aligned);
+    Branch(WordAnd(top, IntPtrConstant(kDoubleAlignmentMask - kHeapObjectTag)),
+           &not_aligned, &aligned);
 
     Bind(&not_aligned);
     Node* not_aligned_size =