diff --git a/compiler-rt/lib/scudo/standalone/local_cache.h b/compiler-rt/lib/scudo/standalone/local_cache.h
--- a/compiler-rt/lib/scudo/standalone/local_cache.h
+++ b/compiler-rt/lib/scudo/standalone/local_cache.h
@@ -189,7 +189,7 @@
     for (uptr I = 0; I < NumClasses; I++) {
       PerClass *P = &PerClassArray[I];
       const uptr Size = SizeClassAllocator::getSizeByClassId(I);
-      P->MaxCount = 2 * TransferBatch::getMaxCached(Size);
+      P->MaxCount = static_cast<u16>(2 * TransferBatch::getMaxCached(Size));
       if (I != BatchClassId) {
         P->ClassSize = Size;
       } else {
@@ -221,7 +221,8 @@
   NOINLINE void drain(PerClass *C, uptr ClassId) {
     const u16 Count = Min(static_cast<u16>(C->MaxCount / 2), C->Count);
     Allocator->pushBlocks(this, ClassId, &C->Chunks[0], Count);
-    C->Count -= Count;
+    // u16 will be promoted to int by arithmetic type conversion.
+    C->Count = static_cast<u16>(C->Count - Count);
     for (u16 I = 0; I < C->Count; I++)
       C->Chunks[I] = C->Chunks[I + Count];
   }