[llvm-dev] llvm (the middle-end) is getting slower, December edition

Davide Italiano via llvm-dev
2016-12-21T16:07:12Z

On Mon, Dec 19, 2016 at 4:24 PM, Mikhail Zolotukhin
<mzolotukhin at apple.com> wrote:
> Hi Davide,
>
> Thanks for the analysis, it's really interesting! And I'm really
glad that we now put more and more attention at the compile time!
>
> Just recently I've been looking into historical compile time data as
well, and have had similar conclusions. The regressions you've found are
probably caused by:
> 1) r289813 and r289855 - new matchers in InstCombine
> 2) r286814 and r288024 - changes in Inlining cost model
>

Haven't looked at 2) yet, but I can confirm for 1). Sanjay/Ehsan, can
you please explain what's the motivation behind the new
transformations you introduced? I'm tempted to ask a revert, but I'd
like to understand the motivations first.

--
Davide

"There are no solved problems; there are only problems that are more
or less solved" -- Henri Poincare