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path: root/target/linux/generic/patches-2.6.39/201-extra_optimization.patch
blob: 8039c665239fdb84ed11d2b8e6e2b71297e26b5e (plain)
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--- a/Makefile
+++ b/Makefile
@@ -543,9 +543,9 @@ endif # $(dot-config)
 all: vmlinux
 
 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
-KBUILD_CFLAGS	+= -Os
+KBUILD_CFLAGS	+= -Os -fno-caller-saves
 else
-KBUILD_CFLAGS	+= -O2
+KBUILD_CFLAGS	+= -O2 -fno-reorder-blocks -fno-tree-ch -fno-caller-saves
 endif
 
 include $(srctree)/arch/$(SRCARCH)/Makefile
@@ -600,6 +600,9 @@ endif
 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 CHECKFLAGS     += $(NOSTDINC_FLAGS)
 
+# improve gcc optimization
+CFLAGS += $(call cc-option,-funit-at-a-time,)
+
 # warn about C99 declaration after statement
 KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)