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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/103755] {has,use}_facet() and iostream constructor performance Date: Sun, 19 Dec 2021 13:04:33 +0000 [thread overview] Message-ID: <bug-103755-4-Xy7kyFW8WG@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-103755-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103755 --- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Dmitry Prokoptsev from comment #6) > That would also work, I suppose (it even outperforms my original approach by > a tiny bit -- 33 ns for v2 vs 36 for my original implementation). > > There are a few build errors in the alternative implementations, however: > is_convertible<locale::facet*, _Facet*>::value is false, as it tries to > downcast the facet -- did you mean is_base_of<>, which would also better > align with the static assert message? Yes, I've already changed it to use that in my local branch. > Also, despite the always_inline attribute of __try_use_facet, my attempts to > build the library with -O0 -ggdb and link my benchmark yielded a bunch of > errors like > > ld: > /home/av/prgs/gcc/debug/x86_64-pc-linux-gnu/libstdc++-v3/src/.libs/libstdc++. > so: undefined reference to `std::num_get<char, > std::istreambuf_iterator<char, std::char_traits<char> > > const* > std::__try_use_facet<std::num_get<char, std::istreambuf_iterator<char, > std::char_traits<char> > > >(std::locale const&)' Yes, that's what happens for the debug libs built with --enable-libstdcxx-debug > Suggest explicitly instantiating __try_use_facet where has_facet() and > use_facet() is instantiated. Yes, I wanted to avoid that :-( > See attached fix for build problems I discovered. Thanks, I'll compare it with the fixes I've already got locally and finish retesting.
next prev parent reply other threads:[~2021-12-19 13:04 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-12-17 3:49 [Bug libstdc++/103755] New: " dprokoptsev at gmail dot com 2021-12-17 10:31 ` [Bug libstdc++/103755] " redi at gcc dot gnu.org 2021-12-17 17:22 ` redi at gcc dot gnu.org 2021-12-17 17:52 ` redi at gcc dot gnu.org 2021-12-17 21:05 ` redi at gcc dot gnu.org 2021-12-19 3:41 ` dprokoptsev at gmail dot com 2021-12-19 3:44 ` dprokoptsev at gmail dot com 2021-12-19 13:04 ` redi at gcc dot gnu.org [this message] 2022-02-03 17:06 ` redi at gcc dot gnu.org 2022-09-23 12:57 ` redi at gcc dot gnu.org 2022-11-11 5:29 ` cvs-commit at gcc dot gnu.org 2022-11-11 13:27 ` redi at gcc dot gnu.org 2022-11-11 21:54 ` seurer at gcc dot gnu.org 2022-11-11 21:55 ` redi at gcc dot gnu.org 2022-11-11 22:39 ` redi at gcc dot gnu.org 2022-11-12 1:30 ` cvs-commit at gcc dot gnu.org 2022-11-12 2:00 ` redi at gcc dot gnu.org 2023-01-06 12:12 ` redi at gcc dot gnu.org 2023-01-11 14:07 ` redi at gcc dot gnu.org 2023-04-21 15:01 ` cvs-commit at gcc dot gnu.org 2023-04-21 15:06 ` redi at gcc dot gnu.org
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