Re: [boost] [review] **NEXT WEEK** Review of Outcome (starts Fri-19-May)

Subject: Re: [boost] [review] **NEXT WEEK** Review of Outcome (starts Fri-19-May)
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2017-05-14 11:33:08

>> But I can see a feature like __builtin_expect that going the way of the
>> dodo as the compiler vendors really would prefer if you used profile
>> guided optimisation instead. Passing that sort of micro-info from the
>> parser to the backend is surely complex to get right.
> 
> I looked for bug reports about __builtin_expect in gcc's bugzilla, and
> the only relevant one I found was
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59521 about using it in a
> switch. Could you back your statement with some links? Otherwise it
> sounds like FUD (at least the part about ignoring multiple persistent
> reports).

It's possible my memory is faulty, but I don't think it was. It was a
very good talk, basically a long list with extensive microdetail of how
compiler version quirks get in the way of micro optimisation. Builtin
expect was but one of many in a long list.

The presenter, Jason McGuiness, is one of the more colourful regular
attendees at ACCU and from all my interactions with him to date, I would
be considering him to not be FUDing. He's presented similar material at
ACCU London talks and several others.

His slides for the ACCU talk aren't online yet, so I'm sent him a
LinkedIn request and I'll ask for a copy. I'll post a link here if I get
them.

Niall

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