diff --git a/compiler-rt/lib/scudo/standalone/tests/mutex_test.cpp b/compiler-rt/lib/scudo/standalone/tests/mutex_test.cpp
--- a/compiler-rt/lib/scudo/standalone/tests/mutex_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/mutex_test.cpp
@@ -43,7 +43,7 @@
   void backoff() {
     volatile T LocalData[Size] = {};
     for (scudo::u32 I = 0; I < Size; I++) {
-      LocalData[I]++;
+      LocalData[I] = LocalData[I] + 1;
       EXPECT_EQ(LocalData[I], 1U);
     }
   }