diff --git a/compiler-rt/lib/asan/asan_allocator.h b/compiler-rt/lib/asan/asan_allocator.h
--- a/compiler-rt/lib/asan/asan_allocator.h
+++ b/compiler-rt/lib/asan/asan_allocator.h
@@ -166,16 +166,6 @@
 using PrimaryAllocatorASVT = SizeClassAllocator64<AP64<AddressSpaceView>>;
 using PrimaryAllocator = PrimaryAllocatorASVT<LocalAddressSpaceView>;
 #else  // Fallback to SizeClassAllocator32.
-static const uptr kRegionSizeLog = 20;
-static const uptr kNumRegions = SANITIZER_MMAP_RANGE_SIZE >> kRegionSizeLog;
-# if SANITIZER_WORDSIZE == 32
-template <typename AddressSpaceView>
-using ByteMapASVT = FlatByteMap<kNumRegions, AddressSpaceView>;
-# elif SANITIZER_WORDSIZE == 64
-template <typename AddressSpaceView>
-using ByteMapASVT =
-    TwoLevelByteMap<(kNumRegions >> 12), 1 << 12, AddressSpaceView>;
-# endif
 typedef CompactSizeClassMap SizeClassMap;
 template <typename AddressSpaceViewTy>
 struct AP32 {
@@ -183,9 +173,8 @@
   static const u64 kSpaceSize = SANITIZER_MMAP_RANGE_SIZE;
   static const uptr kMetadataSize = 16;
   typedef __asan::SizeClassMap SizeClassMap;
-  static const uptr kRegionSizeLog = __asan::kRegionSizeLog;
+  static const uptr kRegionSizeLog = 20;
   using AddressSpaceView = AddressSpaceViewTy;
-  using ByteMap = __asan::ByteMapASVT<AddressSpaceView>;
   typedef AsanMapUnmapCallback MapUnmapCallback;
   static const uptr kFlags = 0;
 };
diff --git a/compiler-rt/lib/lsan/lsan_allocator.h b/compiler-rt/lib/lsan/lsan_allocator.h
--- a/compiler-rt/lib/lsan/lsan_allocator.h
+++ b/compiler-rt/lib/lsan/lsan_allocator.h
@@ -51,27 +51,14 @@
 
 #if defined(__mips64) || defined(__aarch64__) || defined(__i386__) || \
     defined(__arm__)
-static const uptr kRegionSizeLog = 20;
-static const uptr kNumRegions = SANITIZER_MMAP_RANGE_SIZE >> kRegionSizeLog;
-
-#if SANITIZER_WORDSIZE == 32
-template <typename AddressSpaceView>
-using ByteMapASVT = FlatByteMap<kNumRegions, AddressSpaceView>;
-#elif SANITIZER_WORDSIZE == 64
-template <typename AddressSpaceView>
-using ByteMapASVT =
-    TwoLevelByteMap<(kNumRegions >> 12), 1 << 12, AddressSpaceView>;
-#endif
-
 template <typename AddressSpaceViewTy>
 struct AP32 {
   static const uptr kSpaceBeg = 0;
   static const u64 kSpaceSize = SANITIZER_MMAP_RANGE_SIZE;
   static const uptr kMetadataSize = sizeof(ChunkMetadata);
   typedef __sanitizer::CompactSizeClassMap SizeClassMap;
-  static const uptr kRegionSizeLog = __lsan::kRegionSizeLog;
+  static const uptr kRegionSizeLog = 20;
   using AddressSpaceView = AddressSpaceViewTy;
-  using ByteMap = __lsan::ByteMapASVT<AddressSpaceView>;
   typedef NoOpMapUnmapCallback MapUnmapCallback;
   static const uptr kFlags = 0;
 };
diff --git a/compiler-rt/lib/msan/msan_allocator.cc b/compiler-rt/lib/msan/msan_allocator.cc
--- a/compiler-rt/lib/msan/msan_allocator.cc
+++ b/compiler-rt/lib/msan/msan_allocator.cc
@@ -46,18 +46,14 @@
 
 #if defined(__mips64)
 static const uptr kMaxAllowedMallocSize = 2UL << 30;
-static const uptr kRegionSizeLog = 20;
-static const uptr kNumRegions = SANITIZER_MMAP_RANGE_SIZE >> kRegionSizeLog;
-typedef TwoLevelByteMap<(kNumRegions >> 12), 1 << 12> ByteMap;
 
 struct AP32 {
   static const uptr kSpaceBeg = 0;
   static const u64 kSpaceSize = SANITIZER_MMAP_RANGE_SIZE;
   static const uptr kMetadataSize = sizeof(Metadata);
   typedef __sanitizer::CompactSizeClassMap SizeClassMap;
-  static const uptr kRegionSizeLog = __msan::kRegionSizeLog;
+  static const uptr kRegionSizeLog = 20;
   using AddressSpaceView = LocalAddressSpaceView;
-  using ByteMap = __msan::ByteMap;
   typedef MsanMapUnmapCallback MapUnmapCallback;
   static const uptr kFlags = 0;
 };
@@ -99,18 +95,14 @@
 typedef SizeClassAllocator64<AP64> PrimaryAllocator;
 #elif defined(__aarch64__)
 static const uptr kMaxAllowedMallocSize = 2UL << 30;  // 2G
-static const uptr kRegionSizeLog = 20;
-static const uptr kNumRegions = SANITIZER_MMAP_RANGE_SIZE >> kRegionSizeLog;
-typedef TwoLevelByteMap<(kNumRegions >> 12), 1 << 12> ByteMap;
 
 struct AP32 {
   static const uptr kSpaceBeg = 0;
   static const u64 kSpaceSize = SANITIZER_MMAP_RANGE_SIZE;
   static const uptr kMetadataSize = sizeof(Metadata);
   typedef __sanitizer::CompactSizeClassMap SizeClassMap;
-  static const uptr kRegionSizeLog = __msan::kRegionSizeLog;
+  static const uptr kRegionSizeLog = 20;
   using AddressSpaceView = LocalAddressSpaceView;
-  using ByteMap = __msan::ByteMap;
   typedef MsanMapUnmapCallback MapUnmapCallback;
   static const uptr kFlags = 0;
 };
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_internal.h b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_internal.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_internal.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_internal.h
@@ -22,22 +22,13 @@
 // purposes.
 typedef CompactSizeClassMap InternalSizeClassMap;
 
-static const uptr kInternalAllocatorRegionSizeLog = 20;
-static const uptr kInternalAllocatorNumRegions =
-    SANITIZER_MMAP_RANGE_SIZE >> kInternalAllocatorRegionSizeLog;
-#if SANITIZER_WORDSIZE == 32
-typedef FlatByteMap<kInternalAllocatorNumRegions> ByteMap;
-#elif SANITIZER_WORDSIZE == 64
-typedef TwoLevelByteMap<(kInternalAllocatorNumRegions >> 12), 1 << 12> ByteMap;
-#endif
 struct AP32 {
   static const uptr kSpaceBeg = 0;
   static const u64 kSpaceSize = SANITIZER_MMAP_RANGE_SIZE;
   static const uptr kMetadataSize = 0;
   typedef InternalSizeClassMap SizeClassMap;
-  static const uptr kRegionSizeLog = kInternalAllocatorRegionSizeLog;
+  static const uptr kRegionSizeLog = 20;
   using AddressSpaceView = LocalAddressSpaceView;
-  using ByteMap = __sanitizer::ByteMap;
   typedef NoOpMapUnmapCallback MapUnmapCallback;
   static const uptr kFlags = 0;
 };
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
@@ -41,7 +41,6 @@
   enum {
     kRandomShuffleChunks = 1,
     kUseSeparateSizeClassForBatch = 2,
-    kForTest = 4,
   };
 };
 
@@ -57,7 +56,7 @@
 template <class Params>
 class SizeClassAllocator32 {
  private:
-  static const u64 TwoLevelByteMapSize1 =
+  static const u64 kTwoLevelByteMapSize1 =
       (Params::kSpaceSize >> Params::kRegionSizeLog) >> 12;
   static const u64 kMinFirstMapSizeTwoLevelByteMap = 4;
 
@@ -68,29 +67,12 @@
   static const uptr kMetadataSize = Params::kMetadataSize;
   typedef typename Params::SizeClassMap SizeClassMap;
   static const uptr kRegionSizeLog = Params::kRegionSizeLog;
-  typedef typename Params::ByteMap ByteMap;
   typedef typename Params::MapUnmapCallback MapUnmapCallback;
-
-#if SANITIZER_WORDSIZE == 32
-  CheckTwoLevelByteMapSize<false, kMinFirstMapSizeTwoLevelByteMap,
-                           TwoLevelByteMapSize1>
-      Check;
-  using BM = FlatByteMap<(Params::kSpaceSize >> Params::kRegionSizeLog),
-                         AddressSpaceView>;
-#elif SANITIZER_WORDSIZE == 64
-  CheckTwoLevelByteMapSize<true, kMinFirstMapSizeTwoLevelByteMap,
-                           TwoLevelByteMapSize1>
-      Check;
-  using BM = TwoLevelByteMap<TwoLevelByteMapSize1, 1 << 12, AddressSpaceView>;
-#endif
-  static_assert((Params::kFlags & SizeClassAllocator32FlagMasks::kForTest) ||
-                    is_same<BM, ByteMap>::value,
-                "Unexpected ByteMap type");
-
-  static_assert(
-
-      is_same<typename ByteMap::AddressSpaceView, AddressSpaceView>::value,
-      "AddressSpaceView type mismatch");
+  using ByteMap = typename conditional<
+      (kTwoLevelByteMapSize1 < kMinFirstMapSizeTwoLevelByteMap),
+      FlatByteMap<(Params::kSpaceSize >> Params::kRegionSizeLog),
+                  AddressSpaceView>,
+      TwoLevelByteMap<kTwoLevelByteMapSize1, 1 << 12, AddressSpaceView>>::type;
 
   COMPILER_CHECK(!SANITIZER_SIGN_EXTENDED_ADDRESSES ||
                  (kSpaceSize & (kSpaceSize - 1)) == 0);
diff --git a/compiler-rt/lib/sanitizer_common/tests/sanitizer_allocator_test.cc b/compiler-rt/lib/sanitizer_common/tests/sanitizer_allocator_test.cc
--- a/compiler-rt/lib/sanitizer_common/tests/sanitizer_allocator_test.cc
+++ b/compiler-rt/lib/sanitizer_common/tests/sanitizer_allocator_test.cc
@@ -143,7 +143,6 @@
 #endif
 
 static const uptr kRegionSizeLog = FIRST_32_SECOND_64(20, 24);
-static const uptr kFlatByteMapSize = kAddressSpaceSize >> kRegionSizeLog;
 
 template <typename AddressSpaceViewTy>
 struct AP32Compact {
@@ -153,9 +152,8 @@
   typedef CompactSizeClassMap SizeClassMap;
   static const uptr kRegionSizeLog = ::kRegionSizeLog;
   using AddressSpaceView = AddressSpaceViewTy;
-  using ByteMap = FlatByteMap<kFlatByteMapSize, AddressSpaceView>;
   typedef NoOpMapUnmapCallback MapUnmapCallback;
-  static const uptr kFlags = SizeClassAllocator32FlagMasks::kForTest;
+  static const uptr kFlags = 0;
 };
 template <typename AddressSpaceView>
 using Allocator32CompactASVT =
@@ -299,11 +297,9 @@
   typedef DefaultSizeClassMap SizeClassMap;
   static const uptr kRegionSizeLog = ::kRegionSizeLog;
   using AddressSpaceView = AddressSpaceViewTy;
-  using ByteMap = FlatByteMap<kFlatByteMapSize, AddressSpaceView>;
   typedef NoOpMapUnmapCallback MapUnmapCallback;
   static const uptr kFlags =
-      SizeClassAllocator32FlagMasks::kUseSeparateSizeClassForBatch |
-      SizeClassAllocator32FlagMasks::kForTest;
+      SizeClassAllocator32FlagMasks::kUseSeparateSizeClassForBatch;
 };
 template <typename AddressSpaceView>
 using Allocator32SeparateBatchesASVT =
@@ -475,9 +471,8 @@
   typedef CompactSizeClassMap SizeClassMap;
   static const uptr kRegionSizeLog = ::kRegionSizeLog;
   using AddressSpaceView = AddressSpaceViewTy;
-  using ByteMap = FlatByteMap<kFlatByteMapSize, AddressSpaceView>;
   typedef TestMapUnmapCallback MapUnmapCallback;
-  static const uptr kFlags = SizeClassAllocator32FlagMasks::kForTest;
+  static const uptr kFlags = 0;
 };
 
 TEST(SanitizerCommon, SizeClassAllocator32MapUnmapCallback) {
diff --git a/compiler-rt/lib/scudo/scudo_allocator.h b/compiler-rt/lib/scudo/scudo_allocator.h
--- a/compiler-rt/lib/scudo/scudo_allocator.h
+++ b/compiler-rt/lib/scudo/scudo_allocator.h
@@ -84,12 +84,6 @@
 };
 typedef SizeClassAllocator64<AP64> PrimaryT;
 #else
-static const uptr NumRegions = SANITIZER_MMAP_RANGE_SIZE >> RegionSizeLog;
-# if SANITIZER_WORDSIZE == 32
-typedef FlatByteMap<NumRegions> ByteMap;
-# elif SANITIZER_WORDSIZE == 64
-typedef TwoLevelByteMap<(NumRegions >> 12), 1 << 12> ByteMap;
-# endif  // SANITIZER_WORDSIZE
 struct AP32 {
   static const uptr kSpaceBeg = 0;
   static const u64 kSpaceSize = SANITIZER_MMAP_RANGE_SIZE;
@@ -97,7 +91,6 @@
   typedef __scudo::SizeClassMap SizeClassMap;
   static const uptr kRegionSizeLog = RegionSizeLog;
   using AddressSpaceView = LocalAddressSpaceView;
-  using ByteMap = __scudo::ByteMap;
   typedef NoOpMapUnmapCallback MapUnmapCallback;
   static const uptr kFlags =
       SizeClassAllocator32FlagMasks::kRandomShuffleChunks |
diff --git a/compiler-rt/lib/tsan/rtl/tsan_rtl.h b/compiler-rt/lib/tsan/rtl/tsan_rtl.h
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl.h
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl.h
@@ -55,21 +55,16 @@
 #if !SANITIZER_GO
 struct MapUnmapCallback;
 #if defined(__mips64) || defined(__aarch64__) || defined(__powerpc__)
-static const uptr kAllocatorRegionSizeLog = 20;
-static const uptr kAllocatorNumRegions =
-    SANITIZER_MMAP_RANGE_SIZE >> kAllocatorRegionSizeLog;
-using ByteMap = TwoLevelByteMap<(kAllocatorNumRegions >> 12), 1 << 12,
-                                LocalAddressSpaceView, MapUnmapCallback>;
+
 struct AP32 {
   static const uptr kSpaceBeg = 0;
   static const u64 kSpaceSize = SANITIZER_MMAP_RANGE_SIZE;
   static const uptr kMetadataSize = 0;
   typedef __sanitizer::CompactSizeClassMap SizeClassMap;
-  static const uptr kRegionSizeLog = kAllocatorRegionSizeLog;
+  static const uptr kRegionSizeLog = 20;
   using AddressSpaceView = LocalAddressSpaceView;
-  using ByteMap = __tsan::ByteMap;
   typedef __tsan::MapUnmapCallback MapUnmapCallback;
-  static const uptr kFlags = SizeClassAllocator32FlagMasks::kForTest;
+  static const uptr kFlags = 0;
 };
 typedef SizeClassAllocator32<AP32> PrimaryAllocator;
 #else