diff --git a/sims/common-sim-flags.mk b/sims/common-sim-flags.mk
index c2ae022c..2b56e989 100644
--- a/sims/common-sim-flags.mk
+++ b/sims/common-sim-flags.mk
@@ -46,4 +46,5 @@ SIM_PREPROC_DEFINES = \
 	+define+RANDOMIZE_MEM_INIT \
 	+define+RANDOMIZE_REG_INIT \
 	+define+RANDOMIZE_GARBAGE_ASSIGN \
-	+define+RANDOMIZE_INVALID_ASSIGN
+	+define+RANDOMIZE_INVALID_ASSIGN \
+	$(EXTRA_SIM_PREPROC_DEFINES)