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Re: Freescale 68HC11/68HC12 port (gcc newbie help request)

On Wed, 2012-03-21 at 15:12 -0700, Ian Lance Taylor wrote:
> I can understand why you are doing this.  However, you should be aware
> that the compiler internals changed significantly in version 4.0.  Time
> spent working on detailed optimizations of gcc 3.4 is almost certainly
> time wasted.  Walking forward version by version makes some sense, I
> guess, but you shouldn't even look at the optimizations in the generated
> code until you get to at least 4.3.

Thanks for the advice. After a number of days fumbling around, I think
I'm going to concede defeat for the time being (!)

I have brought the code forwards a little bit but at each step there are
hurdles to overcome, using a current build environment highlights
ancient hidden bugs in the gcc code. The m68hc11 code too is frequently
struck by ICEs due to insn not matching contraints and the like.

The commentary in the 2003 gcc conference proceedings regarding the
difficulty of bringing stagnant targets up to date is spot on. Seeing
that it took 2 developers from MIPs six months to revive their target...
I realise that I do not have the time (or skill) to presently undertake
this task. Also the m68hc11 is (was) a minority target.

However, I do think I'm able to make some small improvements on the
3.3.6 code for m68hc11 and will use that internally.



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