Add build option -fomit-frame-pointer.
It seems to improve code generation.
diff --git a/Makefile b/Makefile
index 50a29d5..6938bef 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@
# Default compiler flags
COMMONCFLAGS = -Wall -Os -MD -m32 -march=i386 -mregparm=2 \
- -ffreestanding -fwhole-program
+ -ffreestanding -fwhole-program -fomit-frame-pointer
COMMONCFLAGS += $(call cc-option,$(CC),-nopie,)
COMMONCFLAGS += $(call cc-option,$(CC),-fno-stack-protector,)
COMMONCFLAGS += $(call cc-option,$(CC),-fno-stack-protector-all,)