--- old/make/hotspot/lib/JvmFeatures.gmk	2018-03-23 16:35:43.204228215 +0000
+++ new/make/hotspot/lib/JvmFeatures.gmk	2018-03-23 16:35:42.604287536 +0000
@@ -152,8 +152,8 @@
   # optimization level instead. This activates O3 on slowdebug builds, just
   # like the old build, but it's probably not right.
   JVM_OPTIMIZATION :=
-  JVM_CFLAGS_FEATURES += -O3 -flto
-  JVM_LDFLAGS_FEATURES += -O3 -flto -fuse-linker-plugin -fno-strict-aliasing
+  JVM_CFLAGS_FEATURES += -O0 -flto
+  JVM_LDFLAGS_FEATURES += -O0 -flto -fuse-linker-plugin -fno-strict-aliasing
 endif
 
 ifeq ($(call check-jvm-feature, minimal), true)