[ColdFire 9/63] Add -mcpu, -march, -mtune, and related options

[Ian Lance Taylor]

Roman Zippel <zippel@linux-m68k.org> writes:

> Everything else has -mcpu and/or -march with an optional -mtune and I 
> would strongly tend to do the same (with the weak tendency to just use 
> -march).

In my experience that main advantage of distinguishing -mcpu and
-march is that specific versions of CPUs may require specific fixes to
work around errors in the implementation of the ISA.  We see this on
MIPS for -mfix-r4000, -mfix-r4400, etc.  When I've implemented
backends, I arrange for -mcpu=XXX to enable these fixups, as distinct
from -march=XXX which simply sets the ISA.  This is of course most
useful when there are different versions of a processor intended to
support the same ISA.

Ian