[patch 2/9] autoselect optimal -mcpu= flag by platform

[Segher Boessenkool]

> Is there a reason we don't distinguish between 7400/7410 and 74{4,5}
> x?  Is it because we dont have any discrete systems with just a 7400
> on it?

It's quite important for 74[01]0 systems to not run
code tuned for 7450.  Older Macs have such CPUs, the
user should have the option to tune for it.

> Also I'd suggest we have the config options be a 1:1 matching for the
> -mcpu/-mtune options in gcc for the following cases:
>
>> +	default "-mcpu=750" if CPU_7xx
>> +	default "-mcpu=7450" if CPU_74xx
>> +	default "-mcpu=860" if PPC_8xx
>> +	default "-mcpu=8540" if PPC_85xx

It would be good to do that for all cases, unfortunately
GCC doesn't recognise all CPU/core names as -mcpu options.


Segher