[Bug c++/94781] version 9.3 g++ compilation time is slower by 20% or much more (closer to 50 % sometimes) in comparison to v7.

marxin at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Wed May 6 08:59:02 GMT 2020


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94781

--- Comment #9 from Martin Liška <marxin at gcc dot gnu.org> ---
Thanks.
I've made a more permanent link here:
https://drive.google.com/file/d/1s9i_l68CR8UGhqPfq0pdgQTH26G7YEFW/view?usp=sharing

I get these numbers for g++ UnifiedBindings23-v7.cpp -c -std=c++17 -O2
-fno-checking -fmax-errors=1 -Wno-invalid-offsetof:

  7.4.0 (adafdb1e7212d53a)(06 Dec 2018 10:00): [took: 68.766s] result: OK
  7.5.0 (b2d961e7342b5ba4)(14 Nov 2019 07:40): [took: 68.694s] result: OK
  8.1.0 (406c2abec3f998e9)(02 May 2018 10:13): [took: 73.308s] result: OK
  8.2.0 (ddeb81e76461fc00)(26 Jul 2018 09:47): [took: 72.738s] result: OK
  8.3.0 (4c44b708f11eec6f)(22 Feb 2019 14:20): [took: 72.058s] result: OK
  8.4.0 (8cd3bffead2ed1d1)(04 Mar 2020 08:30): [took: 71.730s] result: OK
  9.1.0 (c8913260b0756f97)(03 May 2019 07:59): [took: 77.404s] result: OK
  9.2.0 (a0c06cc27d2146b7)(12 Aug 2019 09:38): [took: 76.432s] result: OK
  9.3.0 (4212a6a3e44f8704)(12 Mar 2020 11:08): [took: 76.636s] result: OK

current master:
  438085cc66ed5801(05 May 2020 12:24)(Michael Meissner meissner@linux.ibm.com):
[took: 78.698s] result: OK

Which is a regression of ~12% and one can't point to a single point where it
jumped rapidly. Note that we do more inlining and more optimizations in
general.


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