diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h
@@ -635,8 +635,8 @@
     return kUsingConstantSpaceBeg ? kSpaceBeg : NonConstSpaceBeg;
   }
   uptr SpaceEnd() const { return  SpaceBeg() + kSpaceSize; }
-  // kRegionSize must be >= 2^32.
-  COMPILER_CHECK((kRegionSize) >= (1ULL << (SANITIZER_WORDSIZE / 2)));
+  // kRegionSize should be able to satisfy the largest size class.
+  static_assert(kRegionSize >= SizeClassMap::kMaxSize);
   // kRegionSize must be <= 2^36, see CompactPtrT.
   COMPILER_CHECK((kRegionSize) <= (1ULL << (SANITIZER_WORDSIZE / 2 + 4)));
   // Call mmap for user memory with at least this size.