Index: source/lib/code_annotation.h
===================================================================
--- source/lib/code_annotation.h
+++ source/lib/code_annotation.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2021 Wildfire Games.
+/* Copyright (c) 2023 Wildfire Games.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -413,4 +413,14 @@
 // TODO: Maybe use __fallthrough for the MSVC code analyzer (also figure out if we need to add some switch when switching to a newer version of VS that supports [[fallthrough]]
 #endif
 
+// Using of [[likely]]/[[unlikely]] should be avoided in a regular code.
+// Ideally we should use PGO.
+#if CLANG_VERSION || GCC_VERSION
+#define IF_LIKELY(EXPRESSION) if (__builtin_expect(static_cast<bool>(EXPRESSION), 1))
+#define IF_UNLIKELY(EXPRESSION) if (__builtin_expect(static_cast<bool>(EXPRESSION), 0))
+#else
+#define IF_LIKELY(EXPRESSION) if (EXPRESSION)
+#define IF_UNLIKELY(EXPRESSION) if (EXPRESSION)
+#endif
+
 #endif	// #ifndef INCLUDED_CODE_ANNOTATION
Index: source/lib/debug.h
===================================================================
--- source/lib/debug.h
+++ source/lib/debug.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2022 Wildfire Games.
+/* Copyright (C) 2023 Wildfire Games.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -290,9 +290,9 @@
 #define ENSURE(expr)\
 	do\
 	{\
-		static atomic_bool suppress__;\
-		if(!(expr))\
+		IF_UNLIKELY(!(expr))\
 		{\
+			static atomic_bool suppress__;\
 			switch(debug_OnAssertionFailure(WIDEN(#expr), &suppress__, WIDEN(__FILE__), __LINE__, __func__))\
 			{\
 			case ER_CONTINUE:\