diff --git a/src/Rules.LXifort.mk b/src/Rules.LXifort.mk
index 7981183d73c46e9ead05d0bdfdf854aeb31da239..e02af5381750850b1ed07cccf7fa831851233f99 100644
--- a/src/Rules.LXifort.mk
+++ b/src/Rules.LXifort.mk
@@ -146,9 +146,11 @@ include Makefile.MESONH.mk
 #                                                        #
 ##########################################################
 # Juan & Maud 20/03/2008 --> Ifort 10.1.008 Bug O2 optimization
-OPT_PERF1  =  -O1
+ifneq "$(OPTLEVEL)" "DEBUG"
+OPT_PERF1  =  -O1 
 OBJS_O1= spll_schu.o spll_ps2str.o spll_p_abs.o spll_ini_one_way_n.o spll_urban_solar_abs.o
 $(OBJS_O1) : OPT = $(OPT_BASE) $(OPT_PERF1)
+endif
 
 ifneq "$(findstring 8,$(LFI_INT))" ""
 OBJS_I8=spll_NEWLFI_ALL.o