gcc/config/x-cflags-O1 - gcc - Git at Google

 # At -O0 cc1 etc. are too large on some targets for successful
 # link; force building libbackend.a with -O1.
 ifeq ($(filter-out -O0,$(lastword $(filter -O%,$(CFLAGS)))),)
 $(OBJS) : override CFLAGS += -O1
 endif
	# At -O0 cc1 etc. are too large on some targets for successful
	# link; force building libbackend.a with -O1.
	ifeq ($(filter-out -O0,$(lastword $(filter -O%,$(CFLAGS)))),)
	$(OBJS) : override CFLAGS += -O1
	endif