flags.txt

compiler
-flto -Os
-fno-exceptions
-fno-rtti

-mtune=native
-fdelete-null-pointer-checks
-fno-math-errno (as the less abrasive compare to -ffast-math)
-mlong-calls
-Wall
-mcpu=cortex-m3
-mthumb

-fmessage-length=0
-mfloat-abi=hard
-fno-builtin (?)
--combine (?)Pass multiple source files to compiler at once
-fwhole-program

linker
-specs=nano.specs


CFLAGS = -ffunction-sections -fdata-sections
CXXFLAGS = -fno-rtti -fno-exceptions -Os -fdata-sections -ffunction-sections -Wl,-gc-sections ...
LDFLAGS = -Wl,-gc-sections -fno-exceptions -fno-rtti ...


-fshort-enums
-finline-limit

LDFLAGS: [-Wl,--gc-sections -flto -L../../tools/gcc-arm-none-eabi-4_9-2015q2/arm-none-eabi/lib/armv6-m -L../../tools/gcc-arm-none-eabi-4_9-2015q2/lib/gcc/arm-none-eabi/4.9.3/armv6-m -Xlinker -Map=_build/testing_s110_xxaa.map -mcpu=cortex-m0 -mthumb -mabi=aapcs -L../../sdk_v6_1/nrf51822/Source/templates/gcc/ -Tgcc_nrf51_s110_xxaa.ld --specs=nano.specs -lc -lnosys]

CFLAGS: [-DDEBUG_NRF_USER -DBLE_STACK_SUPPORT_REQD -DSPI_MASTER_0_ENABLE -DNRF51 -DTOOLCHAIN_GCC_ARM -fno-strict-aliasing -ffunction-sections -fdata-sections -mcpu=cortex-m0 -mthumb -mabi=aapcs -DNRF51 -DBOARD_NRF6310 -DNRF51822_QFAA_CA --std=gnu99 -Wall -o0 -fno-common -fmessage-length=0 -mfloat-abi=soft -fno-exceptions -ffunction-sections -fdata-sections -fomit-frame-pointer --specs=nano.specs ]


https://www.anet3d-forum.de/viewtopic.php?t=689

Bed Auto Lvl - Grid; = AUTO_BED_LEVELING_LINEAR?

#define STATUS_MESSAGE_SCROLLING <- try
//#define LCD_INFO_MENU // enabled, shows useless 'about printer' menu
//#define SHOW_CUSTOM_BOOTSCREEN // enabled
//#define CUSTOM_STATUS_SCREEN_IMAGE // enabled
#define NO_VOLUMETRICS // disabled, not used without width sensor?

-Xlinker ??
-flto -fuse-linker-plugin -fno-fat-lto-objects
-Wl,--gc-sections,--relax
-fpack-struct
-funsafe-math-optimizations
-MMD ???

-Oz instead of -Os

-march=armv7-m  -mcpu=cortex-m3
--target=arm-none-eabi (arm-none-eabi-gcc)
-fmessage-length=0
-Wall -Wextra ???
-mfix-cortex-m3-ldrd ??

new lib nano (--enable-newlib-io-long-long)
-fomit-frame-pointer: tell GCC to optimize for size, not for speed
-mfloat-abi=softfp