https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125334
Bug ID: 125334
Summary: [16/17 Regression] basic std module example compile
time doubles when <bits/stdc++.h> is built as header
unit
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ppalka at gcc dot gnu.org
Target Milestone: ---
$ cat testcase.C
import std;
int main() {
std::cout << 123 << std::endl;
}
$ CC=g++-15
$ rm -rf gcm.cache
$ $CC -fmodules -std=c++20 -fsearch-include-path bits/std.cc
$ perf stat -r10 $CC -fmodules -std=c++20 testcase.C
...
0.341537423 +- 0.002332826 seconds time elapsed ( +- 0.68% )
$ rm -rf gcm.cache
$ $CC -fmodules -std=c++20 -fsearch-include-path bits/stdc++.h bits/std.cc
$ perf stat -r10 $CC -fmodules -std=c++20 testcase.C
...
0.356897251 +- 0.002575109 seconds time elapsed ( +- 0.72% )
$ CC=g++-16
$ rm -rf gcm.cache
$ $CC -fmodules -std=c++20 -fsearch-include-path bits/std.cc
$ perf stat -r10 $CC -fmodules -std=c++20 testcase.C
...
0.374096264 +- 0.002264572 seconds time elapsed ( +- 0.61% )
$ rm -rf gcm.cache
$ $CC -fmodules -std=c++20 -fsearch-include-path bits/stdc++.h bits/std.cc
$ perf stat -r10 $CC -fmodules -std=c++20 testcase.C
...
0.756065966 +- 0.002910919 seconds time elapsed ( +- 0.39% )
