diff --git a/newlib/libc/include/sys/cdefs.h b/newlib/libc/include/sys/cdefs.h
index d13a92a79..20b3553dc 100644
--- a/newlib/libc/include/sys/cdefs.h
+++ b/newlib/libc/include/sys/cdefs.h
@@ -736,7 +736,7 @@
 /* Provide fallback versions for other compilers (GCC/Clang < 10): */
 #if !__has_builtin(__builtin_is_aligned)
 #define __builtin_is_aligned(x, align)	\
-	(((__uintptr_t)x & ((align) - 1)) == 0)
+	(((__uintptr_t)(x) & ((align) - 1)) == 0)
 #endif
 #if !__has_builtin(__builtin_align_up)
 #define __builtin_align_up(x, align)	\