diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7730bf08..705abd64 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -553,7 +553,9 @@ if(MI_TRACK_ASAN)
 endif()
 string(TOLOWER "${CMAKE_BUILD_TYPE}" CMAKE_BUILD_TYPE_LC)
 list(APPEND mi_defines "MI_CMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE_LC}")  #todo: multi-config project needs $<CONFIG> ?
-if(NOT(CMAKE_BUILD_TYPE_LC MATCHES "^(release|relwithdebinfo|minsizerel|none)$"))
+if(CMAKE_BUILD_TYPE_LC MATCHES "^(release|relwithdebinfo|minsizerel|none)$")
+  list(APPEND mi_defines MI_BUILD_RELEASE)
+else()
   set(mi_libname "${mi_libname}-${CMAKE_BUILD_TYPE_LC}") #append build type (e.g. -debug) if not a release version
 endif()
 
diff --git a/include/mimalloc/types.h b/include/mimalloc/types.h
index 0a60517c..d5df5f4a 100644
--- a/include/mimalloc/types.h
+++ b/include/mimalloc/types.h
@@ -69,10 +69,10 @@ terms of the MIT license. A copy of the license can be found in the file
 // #define MI_DEBUG 2  // + internal assertion checks
 // #define MI_DEBUG 3  // + extensive internal invariant checking (cmake -DMI_DEBUG_FULL=ON)
 #if !defined(MI_DEBUG)
-#if !defined(NDEBUG) || defined(_DEBUG)
-#define MI_DEBUG 2
-#else
+#if defined(MI_BUILD_RELEASE) || defined(NDEBUG)
 #define MI_DEBUG 0
+#else
+#define MI_DEBUG 2
 #endif
 #endif