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Re: Combine four insns
On 08/16/2010 10:37 PM, Mark Mitchell wrote:
> Richard Guenther wrote:
>
>>> We would all like fast compilation, but if you specify -Os, it seems to me
>>> that you are expressing a preference for smaller code.
>>
>> Yes indeed.
>
> I agree; it's OK for -Os to take more compilation time just as it's OK
> for -O2 to take more compilation time. It's just optimization on a
> different axis.
>
> Where are we with Bernd's patch to combine four instructions at this
> point? Does it need review, or are we still not sure it's a good idea?
I was going to use Richard's earlier approval and check in the revised
version some time this week after a bit more testing. I experimented
with Michael's heuristic last week, without getting useful results, so
I'll use the one I previously posted. My plan was to disable the
heuristic (i.e. try all possible four-insn combinations) only at -O3
since we don't have -Os3 but I could of course do the same for -Os as well.
Bernd