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[Bug libstdc++/14078] Manipulators are slow
- From: "pcarlini at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 10 Feb 2004 16:09:30 -0000
- Subject: [Bug libstdc++/14078] Manipulators are slow
- References: <20040209093043.14078.peturr02@ru.is>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From pcarlini at suse dot de 2004-02-10 16:09 -------
> The only reason I suggested that the argument should be declared const is
> that it seems to make a difference in practice (in fact, about 44%). I
> don't know why it does though, the compiler should be able to figure out
> on it's own that pf isn't modified in the body of the function.
These are well known deficiencies of the inliner
http://gcc.gnu.org/ml/libstdc++/2003-02/msg00302.html
which, I'm told, should be already fixed "automatically" in the tree-ssa
branch. For this reason, I'd rather prefer not adding the "redundant" const
in the signature, even if (thanks for pointing that out!) technically it would
still be conforming. Anyway, I'm going to add to the performance testsuite a
snippet distilled from your manipspeed, so we'll be able to track the issue in
the future. Thanks again for your report.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14078