diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
@@ -69,10 +69,16 @@
 # else
 #  define SANITIZER_IOSSIM 0
 # endif
+#if SANITIZER_IOS || SANITIZER_IOSSIM
+#define SANITIZER_OSX 0
+#else
+#define SANITIZER_OSX 1
+#endif
 #else
 # define SANITIZER_MAC     0
 # define SANITIZER_IOS     0
 # define SANITIZER_IOSSIM  0
+#define SANITIZER_OSX 0
 #endif
 
 #if defined(__APPLE__) && TARGET_OS_IPHONE && TARGET_OS_WATCH
@@ -259,7 +265,7 @@
 #elif SANITIZER_RISCV64
 #define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 38)
 #elif defined(__aarch64__)
-# if SANITIZER_MAC
+#if SANITIZER_MAC && !SANITIZER_OSX
 // Darwin iOS/ARM64 has a 36-bit VMA, 64GiB VM
 #  define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 36)
 # else