Subject: Re: 440 ebony patch seems to have broken 85xx build on powerpc.git

From: Segher Boessenkool <[email-masked]>
Date: Fri, 25 May 2007 00:02:44 +0200

>>> Nothing is telling GCC what CPU to compile for, so it
>>> will just use the compiler's default, which very likely
>>> is not what you want. =A0For files that will only ever
>>> be used on 440, the correct flags are -mcpu=3D440 -Wa,-m440 .
>>
>> We could add that to the per-file flags already, right?
>
> I think it should really use -mcpu=3Dpowerpc on all files.
> The problem that Dave saw was the result of using a compiler
> that defaults to -mcpu=3D8540, which uses instruction that
> don't work on 440.

No, those options _do_ work on 440, but the -mbooke
assembler flag disallows isel (since it is an optional
insn).

> The common files really need to be built with -mcpu flags that
> make the code work on any system if you want to be able
> to use just a single boot wrapper binary for all.

On any system where they can run at all, yes.  It should
be fine to compile a 440-only file with 440-specific flags.

Segher