| 1 | --- a/Makefile |
| 2 | +++ b/Makefile |
| 3 | @@ -559,9 +559,9 @@ endif # $(dot-config) |
| 4 | all: vmlinux |
| 5 | |
| 6 | ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE |
| 7 | -KBUILD_CFLAGS += -Os |
| 8 | +KBUILD_CFLAGS += -Os -fno-caller-saves |
| 9 | else |
| 10 | -KBUILD_CFLAGS += -O2 |
| 11 | +KBUILD_CFLAGS += -O2 -fno-reorder-blocks -fno-tree-ch -fno-caller-saves |
| 12 | endif |
| 13 | |
| 14 | include $(srctree)/arch/$(SRCARCH)/Makefile |
| 15 | @@ -620,6 +620,9 @@ endif |
| 16 | NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) |
| 17 | CHECKFLAGS += $(NOSTDINC_FLAGS) |
| 18 | |
| 19 | +# improve gcc optimization |
| 20 | +CFLAGS += $(call cc-option,-funit-at-a-time,) |
| 21 | + |
| 22 | # warn about C99 declaration after statement |
| 23 | KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,) |
| 24 | |
| 25 | |
