[U-Boot] [PATCH] powerpc/nand spl: link libgcc

[Wolfgang Denk]

Dear Scott Wood,

In message <20101210230051.GA30739 at udp111988uds.am.freescale.net> you wrote:
> Recent GCC (4.4+) performs out-of-line epilogues in some cases, when
> optimizing for size.  It causes a link error for _restgpr_30_x (and similar)
> if libgcc is not linked.
> 
> It actually increases size with very small binaries, due to the fixed size
> of the out-of-line code, and not having any functions that actually need to
> restore more than 2 or 3 registers.  But I don't see a way to turn it off,
> other than asking GCC to optimize for speed -- which may also increase
> size for some boards.
> 
> Signed-off-by: Scott Wood <scottwood at freescale.com>
> ---
>  nand_spl/board/amcc/acadia/Makefile           |    2 +-
>  nand_spl/board/amcc/bamboo/Makefile           |    2 +-
>  nand_spl/board/amcc/canyonlands/Makefile      |    2 +-
>  nand_spl/board/amcc/kilauea/Makefile          |    2 +-
>  nand_spl/board/amcc/sequoia/Makefile          |    2 +-
>  nand_spl/board/freescale/mpc8313erdb/Makefile |    2 +-
>  nand_spl/board/freescale/mpc8315erdb/Makefile |    2 +-
>  nand_spl/board/sheldon/simpc8313/Makefile     |    2 +-
>  8 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/nand_spl/board/amcc/acadia/Makefile b/nand_spl/board/amcc/acadia/Makefile
> index bee24bc..f8ca654 100644
> --- a/nand_spl/board/amcc/acadia/Makefile
> +++ b/nand_spl/board/amcc/acadia/Makefile
> @@ -51,7 +51,7 @@ $(nandobj)u-boot-spl.bin:	$(nandobj)u-boot-spl
>  	$(OBJCOPY) ${OBJCFLAGS} -O binary $< $@
>  
>  $(nandobj)u-boot-spl:	$(OBJS) $(nandobj)u-boot.lds
> -	cd $(LNDIR) && $(LD) $(LDFLAGS) $(__OBJS) \
> +	cd $(LNDIR) && $(LD) $(LDFLAGS) $(__OBJS) $(PLATFORM_LIBS) \
>  		-Map $(nandobj)u-boot-spl.map \
>  		-o $(nandobj)u-boot-spl

Just two questions:

Q1: Are we sure that the observed behaviour is intentional, and not
    eventually unintended behaviour (well, a bug) in the new versions
    of GCC?  In general newer releases are supposed to provide better
    optimization, but with GCC regressions seem to be more common?

Q2: What happens with older compilers, that don't need this?  Is this
    change a No-Op for these?


Best regards,

Wolfgang Denk

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