Re: [kbuild-all] mipsel-linux-gnu-gcc: error: unrecognized command line option '-mcompact-branches=optimal'

[Maciej W. Rozycki]

On Thu, 21 Apr 2016, Ralf Baechle wrote:

> >  I don't think it makes sense as the compiler won't support MIPSr6 code 
> > anyway, so first it'll bail out on `-march=mips32r6', and if we go even 
> > further and disable that too, then GAS will probably break somewhere on 
> > inline asm and GCC will produce code which does not make sense otherwise.
> 
> GCC 5.2.0 claims to support mips32r6 and mips64r6.  It's just the option
> -mcompact-branches which seem to have been added later only.

 Ah, I see -- I didn't track the timeline of support for this compiler's 
option and I took it from an earlier response that the compiler does not 
support R6 at all.

 In that case however it looks to me like these `-mcompact-branches=' 
options (all the three we support) need to be wrapped into `$(call 
cc-option,...)'.  They do not affect any functionality and they are an 
optimisation choice only anyway (and therefore I wonder why they've been 
placed in arch/mips/Kconfig.debug rather than arch/mips/Kconfig).

  Maciej