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From: "ed at catmur dot uk" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/110835] New: -fsanitize=address causes slowdown from
 std::rethrow_exception not called
Date: Fri, 28 Jul 2023 04:53:15 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Version: 14.0
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X-Bugzilla-Severity: normal
X-Bugzilla-Who: ed at catmur dot uk
X-Bugzilla-Status: UNCONFIRMED
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X-Bugzilla-Priority: P3
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110835

            Bug ID: 110835
           Summary: -fsanitize=3Daddress causes slowdown from
                    std::rethrow_exception not called
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ed at catmur dot uk
  Target Milestone: ---

#include <exception>
std::exception_ptr p;
void f() {
  try { throw 1; } catch(char) { std::rethrow_exception(p); }
}
int main() {
  for (int i =3D 0; i !=3D 100000; ++i)
    try { f(); } catch (...) { }
}

Compiled with -fsanitize=3Daddress (and at -O0 through -O3), this is roughl=
y 30x
slower under gcc 13 than under gcc 12 (4.7s vs 0.15s on my Core i7 3 GHz).

Note that the std::rethrow_exception() is not called, but is still essentia=
l to
exhibit the bug. Also `f` needs to be a separate function (and not `static`=
).
At low optimization levels it can be an iife.=