mboehme added a comment.

In D126061#3585681 <https://reviews.llvm.org/D126061#3585681>, @nikic wrote:

> FYI this change had a measurable effect on compile-time 
> (http://llvm-compile-time-tracker.com/compare.php?from=7acc88be0312c721bc082ed9934e381d297f4707&to=8c7b64b5ae2a09027c38db969a04fc9ddd0cd6bb&stat=instructions),
>  about 0.5% regression for `O0` builds. Not sure if that's expected.

Thanks for the heads-up.

Without more extensive investigation, it's hard to say. I wasn't necessarily 
expecting a slowdown, but I can come up with various hypotheses for what might 
be causing it.

I've seen the instructions on the About 
<http://llvm-compile-time-tracker.com/about.php> page on how to reproduce 
results and will give that a go.

The first thing to analyze would be whether the slowdown occurs only on code 
that uses attributes (heavily) or also on code that doesn't use attributes.

There isn't any single substantial change in the code that would cause an 
obvious slowdown. I could speculate on some potential causes, but it seems 
better to measure instead. Is there any particular tooling that you would 
recommend for comparing profiler runs from two different compiler versions (one 
with my patch, one without)?

I'll post an update here when I find out more.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D126061/new/

https://reviews.llvm.org/D126061

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