diff --git a/src/os.c b/src/os.c
index 0d40912a..b4b78f43 100644
--- a/src/os.c
+++ b/src/os.c
@@ -380,14 +380,15 @@ void* _mi_os_alloc_aligned(size_t size, size_t alignment, bool commit, bool allo
 
   mi_assert_internal(memid->mem.os.size >= size);
   mi_assert_internal(_mi_is_aligned(p,alignment));
-  mi_assert_internal(!commit || memid->initially_committed);
-  mi_assert_internal(!memid->initially_zero || memid->initially_committed);
+  if (commit) { mi_assert_internal(memid->initially_committed); }
+  if (memid->initially_zero) { mi_assert_internal(memid->initially_committed); }
   return p;
 }
 
 
 mi_decl_nodiscard static void* mi_os_ensure_zero(void* p, size_t size, mi_memid_t* memid) {
-  if (p==NULL || size==0 || memid->initially_zero) return p;
+  if (p==NULL || size==0) return p;
+  // ensure committed
   if (!memid->initially_committed) {
     bool is_zero = false;
     if (!_mi_os_commit(p, size, &is_zero)) {
@@ -396,6 +397,8 @@ mi_decl_nodiscard static void* mi_os_ensure_zero(void* p, size_t size, mi_memid_
     }
     memid->initially_committed = true;
   }
+  // ensure zero'd
+  if (memid->initially_zero) return p;
   _mi_memzero_aligned(p,size);
   memid->initially_zero = true;
   return p;