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Re: Compiler slowdowns (was Re: [PATCH] Optimize manual byte swap implementations v2)
Bradley Lucier wrote:
> OK.
>
> Well, I'm seeing an -O1 compile (with some extra passes thrown in, like
> -fschedule-insn2) go from 168 seconds to 228.17 seconds in four months.
> Without a nail to pound down.
The obvious culprit here is IRA, but I may be wrong.
> That's not directly related to -O2 times or whether bswap optimization
> is worth 1% compile time, but I'm guessing that a number of similar
> discussions went on (at least internally) about other patches over those
> four months, and we've ended up with a big difference. (In the PR I
> noted a 13% difference just between September 19 and September 26 of
> last year.)
I think if you can nail down the day in that week and file a separate
PR, something *will* be done.
> I don't ever quite remember seeing such a rate of increase in compile
> time while I've been watching gcc development.
I agree on this.
Paolo