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Re: powercp-linux cross GCC 4.2 vs GCC 4.0.0: -Os code size regression?
Hello Sergei,
On Thu, Jan 17, 2008 at 03:13:59PM +0300, Sergei Poselenov wrote:
> I don't know now, actually, this is what I'm asking. As for the
> target processor - as I stated in the initial message:
>
> ...
> Currently, it builds as following:
> ppc-linux-gcc -g -Os -fPIC -ffixed-r14 -meabi -fno-strict-aliasing
> -D__KERNEL__ -DTEXT_BASE=0xfffc0000 -I/work/psl/tmp/u-boot/include
> -fno-builtin -ffreestanding -nostdinc -isystem
> /opt/eldk-4.2-01-08/usr/bin/../lib/gcc/powerpc-linux/4.2.2/include
> -pipe -DCONFIG_PPC -D__powerpc__ -DCONFIG_4xx -ffixed-r2 -ffixed-r29
> -mstring -msoft-float -Wa,-m440 -mcpu=440 -DCONFIG_440=1 -Wall
> -Wstrict-prototypes -c -o interrupts.o interrupts.c
> ...
>
> Note the "-mcpu=440" switch.
Doh, I missed this, sorry.
>
> I removed all "-ffixed" option (just for test - we surely need them)
> - it doesn't change the size of the resultant gcc-4.2.2 code.
I'm not sure that having -ffixed-r29 is a wise choice when you are
looking for small code size. It might prevent the use of load/store
multiple in prologue and epilogue code.
Regards,
Gabriel