Provide a tagged allocation top pointer.

src/arm64/macro-assembler-arm64.cc

Index: src/arm64/macro-assembler-arm64.cc
diff --git a/src/arm64/macro-assembler-arm64.cc b/src/arm64/macro-assembler-arm64.cc
index fd70711c34ea64eb3f059d27e5f03c498fd45edf..e68929897f950ca638dfb99037b0ba8be5ba34e2 100644
--- a/src/arm64/macro-assembler-arm64.cc
+++ b/src/arm64/macro-assembler-arm64.cc
@@ -3102,9 +3102,6 @@ void MacroAssembler::Allocate(int object_size,
     // The top pointer is not updated for allocation folding dominators.
     Str(result_end, MemOperand(top_address));
   }
-
-  // Tag the object.
-  ObjectTag(result, result);
 }
 
 
@@ -3174,7 +3171,7 @@ void MacroAssembler::Allocate(Register object_size, Register result,
 
   if (emit_debug_code()) {
     Tst(result_end, kObjectAlignmentMask);
-    Check(eq, kUnalignedAllocationInNewSpace);
+    Check(ne, kUnalignedAllocationInNewSpace);
   }
 
   Ccmp(result_end, alloc_limit, NoFlag, cc);
@@ -3184,9 +3181,6 @@ void MacroAssembler::Allocate(Register object_size, Register result,
     // The top pointer is not updated for allocation folding dominators.
     Str(result_end, MemOperand(top_address));
   }
-
-  // Tag the object.
-  ObjectTag(result, result);
 }
 
 void MacroAssembler::FastAllocate(int object_size, Register result,
@@ -3219,8 +3213,6 @@ void MacroAssembler::FastAllocate(int object_size, Register result,
   // Calculate new top and write it back.
   Adds(result_end, result, object_size);
   Str(result_end, MemOperand(top_address));
-
-  ObjectTag(result, result);
 }
 
 void MacroAssembler::FastAllocate(Register object_size, Register result,
@@ -3254,10 +3246,8 @@ void MacroAssembler::FastAllocate(Register object_size, Register result,
 
   if (emit_debug_code()) {
     Tst(result_end, kObjectAlignmentMask);
-    Check(eq, kUnalignedAllocationInNewSpace);
+    Check(ne, kUnalignedAllocationInNewSpace);
   }
-
-  ObjectTag(result, result);
 }
 
 void MacroAssembler::AllocateTwoByteString(Register result,