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Re: Tremendous increase in compile times for 3.4.1 with -mcpu=G5



On Aug 15, 2004, at 6:35 AM, Eric Botcazou wrote:


I believe Sparc V8plus mode is the only thing similar. That might well
have the same problem.

I would not think so. SPARC V8+ is a much more limited mixed mode than PPC
G5 as far as I know. And my understanding is that, in this mode, the
back-end does 64-bit computation behind the back of the middle-end, in
particular of the register allocator which still thinks everything is
32-bit. And of course, as rth would put it, lie to reload and it will have
its revenge (e.g. PR target/12958).

Interesting. My first implementation of PPC G5 was like that, but somebody
(rth I think) wanted it changed to use the current approach, so Fariborz
redid it. I suppose the slowness problem is better than reload crashes
(we never saw any, but that doesn't mean they couldn't have happened).
But it seems like there ought to be a way to do it so you don't have
either problem...



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