diff --git a/build/Android.common_build.mk b/build/Android.common_build.mk
index 3d7b697..9f15294 100644
--- a/build/Android.common_build.mk
+++ b/build/Android.common_build.mk
@@ -275,6 +275,16 @@
   -DVIXL_DEBUG \
   -UNDEBUG
 
+# The latest clang update trips over many of the files in art and never finishes
+# compiling for aarch64 with -O3 (or -O2). Drop back to -O1 while we investigate
+# to stop punishing the build server.
+ifeq ($(TARGET_ARCH),arm64)
+  ifeq ($(USE_CLANG_PLATFORM_BUILD),true)
+    art_debug_cflags += -O1
+    art_non_debug_cflags += -O1
+  endif
+endif
+
 art_host_non_debug_cflags := $(art_non_debug_cflags)
 art_target_non_debug_cflags := $(art_non_debug_cflags)