Re: [RFC ARM] Error if overriding --with-tune by --with-cpu

[Ramana Radhakrishnan <ramana dot gcc at googlemail dot com>]

On Fri, May 30, 2014 at 5:34 PM, James Greenhalgh
<james.greenhalgh@arm.com> wrote:
>
> Hi,
>
> We error in the case where both --with-tune and --with-cpu are specified at
> configure time. In this case, we cannot distinguish this situation from the
> situation where --with-tune was specified at configure time and -mcpu was
> passed on the command line, so we give -mcpu precedence.
>
> This might be surprising if you expect the precedence rules we give
> to the command line options, but we can't change this precedence without
> breaking our definition of -mcpu.
>
> We also promote the warning which used to be thrown in the case of
> --with-arch and --with-cpu to an error.

Ok by me - Especially as Bin has just run into it as part of his
testing. Obviously no one watches these warnings and they don't
realize what's happening under their feet.

>
> I've marked this is an RFC as it isn't clear that configure should be
> catching something like this. Other blatant errors in configuration
> options like passing "--with-languages=c,c++" pass without event.

Well yeah that looks ok .

>
> Tested with a few combinations of configure options with no issues and the
> expected behaviour.
>
> Any opinions, and if not, OK for trunk?


I am going to give this a week for anyone else to pitch in and object
- otherwise please apply it and document this change in behaviour in
the caveats section for the next release (changes.html).

Ramana


>
> Thanks,
> James
>
> ---
> gcc/
>
> 2014-05-30  James Greenhalgh  <james.greenhalgh@arm.com>
>
>         * config.gcc (supported_defaults): Error when passing either
>         --with-tune or --with-arch in conjunction with --with-cpu for ARM.