Index: lib/sanitizer_common/sanitizer_atomic_clang.h
===================================================================
--- lib/sanitizer_common/sanitizer_atomic_clang.h
+++ lib/sanitizer_common/sanitizer_atomic_clang.h
@@ -48,6 +48,14 @@
     typename T::Type v, memory_order mo) {
   (void)mo;
   DCHECK(!((uptr)a % sizeof(*a)));
+#if defined(_MIPS_SIM) && _MIPS_SIM == _ABIO32
+  typedef typename T::Type Type;
+  if (sizeof(*a) == 8) {
+    Type volatile *val_ptr = const_cast<Type volatile *>(&a->val_dont_use);
+    return __mips_sync_fetch_and_add<u64>(
+          reinterpret_cast<u64 volatile *>(val_ptr), (u64)v);
+  }
+#endif
   return __sync_fetch_and_add(&a->val_dont_use, v);
 }
 
@@ -56,6 +64,14 @@
     typename T::Type v, memory_order mo) {
   (void)mo;
   DCHECK(!((uptr)a % sizeof(*a)));
+#if defined(_MIPS_SIM) && _MIPS_SIM == _ABIO32
+  typedef typename T::Type Type;
+  if (sizeof(*a) == 8) {
+    Type volatile *val_ptr = const_cast<Type volatile *>(&a->val_dont_use);
+    return __mips_sync_fetch_and_add<u64>(
+          reinterpret_cast<u64 volatile *>(val_ptr), -((u64)(v)));
+  }
+#endif
   return __sync_fetch_and_add(&a->val_dont_use, -v);
 }