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https://issues.apache.org/jira/browse/STDCXX-492?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12530008
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Martin Sebor commented on STDCXX-492:
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Woohoo! The numbers look awesome!
As for how to enter different overloads into a ChangeLog, I don't have a good
answer for you. I have had the occasional need to distinguish between two or
more overloads of the same function in the past but so far I've always decided
to ignore this detail. It might be worthwhile to look into it some more and
look at some other C++ projects' ChangeLogs to see how they deal with it.
The one change I did make to the format of your ChangeLog is capitalize the
first letter of every sentence for consistency with the most of the rest of our
ChangeLogs.
> std::string::operator+=() slow
> ------------------------------
>
> Key: STDCXX-492
> URL: https://issues.apache.org/jira/browse/STDCXX-492
> Project: C++ Standard Library
> Issue Type: Bug
> Components: 21. Strings
> Affects Versions: 4.1.3
> Environment: gcc 4.1.2 on Linux/x86_64
> Reporter: Mark Brown
> Assignee: Travis Vitek
> Fix For: 4.2
>
> Attachments: 21.string.append.perf.cpp, string.patch
>
>
> Comparing overloads of string::operator+=() in stdcxx with the same functions
> in gcc 4.1.2, stdcxx is up to twice slower than gcc:
> $ time ./op_plus_equal-stdcxx 100000000 0
> real 0m2.241s
> user 0m1.932s
> sys 0m0.204s
> $ time ./op_plus_equal-stdcxx 100000000 1
> real 0m2.540s
> user 0m2.344s
> sys 0m0.196s
> $ time ./op_plus_equal-stdcxx 100000000 2
> real 0m1.492s
> user 0m1.308s
> sys 0m0.184s
> $ time ./op_plus_equal-gcc 100000000 0
> real 0m0.883s
> user 0m0.728s
> sys 0m0.156s
> $ time ./op_plus_equal-gcc 100000000 1
> real 0m1.589s
> user 0m1.424s
> sys 0m0.168s
> $ time ./op_plus_equal-gcc 100000000 2
> real 0m1.131s
> user 0m0.976s
> sys 0m0.156s
> #include <cassert>
> #include <cstdlib>
> #include <string>
> int main (int argc, char *argv[])
> {
> const int N = argc < 2 ? 1 : std::atoi (argv [1]);
> const int op = argc < 3 ? 0 : std::atoi (argv [2]);
> std::string str;
> const std::string x ("x");
> if (op == 0) {
> for (int i = 0; i < N; ++i)
> str += 'x';
> } else if (op == 1) {
> for (int i = 0; i < N; ++i)
> str += "x";
> } else {
> for (int i = 0; i < N; ++i)
> str += x;
> }
> assert (str.size () == std::size_t (N));
> }
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