diff --git a/include/llvm/Support/Allocator.h b/include/llvm/Support/Allocator.h
index 94cf3e85f36..6ef4344f8fc 100644
--- a/include/llvm/Support/Allocator.h
+++ b/include/llvm/Support/Allocator.h
@@ -320,14 +320,6 @@ private:
     for (; I != E; ++I) {
       size_t AllocatedSlabSize =
           computeSlabSize(std::distance(Slabs.begin(), I));
-#ifndef NDEBUG
-      // Poison the memory so stale pointers crash sooner.  Note we must
-      // preserve the Size and NextPtr fields at the beginning.
-      if (AllocatedSlabSize != 0) {
-        sys::Memory::setRangeWritable(*I, AllocatedSlabSize);
-        memset(*I, 0xCD, AllocatedSlabSize);
-      }
-#endif
       Allocator.Deallocate(*I, AllocatedSlabSize);
     }
   }
@@ -337,12 +329,6 @@ private:
     for (auto &PtrAndSize : CustomSizedSlabs) {
       void *Ptr = PtrAndSize.first;
       size_t Size = PtrAndSize.second;
-#ifndef NDEBUG
-      // Poison the memory so stale pointers crash sooner.  Note we must
-      // preserve the Size and NextPtr fields at the beginning.
-      sys::Memory::setRangeWritable(Ptr, Size);
-      memset(Ptr, 0xCD, Size);
-#endif
       Allocator.Deallocate(Ptr, Size);
     }
   }