public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "fcontact at cuveland dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/108554] New: Warning "null pointer dereferece" raised when extracting a unique_ptr from a map and any "-O" flag Date: Thu, 26 Jan 2023 09:13:35 +0000 [thread overview] Message-ID: <bug-108554-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108554 Bug ID: 108554 Summary: Warning "null pointer dereferece" raised when extracting a unique_ptr from a map and any "-O" flag Product: gcc Version: 12.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: fcontact at cuveland dot de Target Milestone: --- I found what I believe might be a false positive with g++ 12 when using the "-Wnull-dereference" warning and a map of unique_ptr with any level of optimisation. This behavior does not show up in GCC 9, 10, and 11. Small but complete example: #include <map> #include <memory> #include <string> #include <utility> int main() { // create and initialize a map std::map<std::string, std::unique_ptr<int>> my_map; my_map["my_key"] = std::make_unique<int>(1); auto it = my_map.find("my_key"); if (it != my_map.end()) { // extract an item from the map auto item = std::move(my_map.extract(it).mapped()); return *item; } return 0; } Compiled with: g++-12 -O -Wnull-dereference <filename> Compiler version: g++ (Compiler-Explorer-Build-gcc--binutils-2.38) 12.2.0 (see https://godbolt.org/z/E9KhTT4f6)
next reply other threads:[~2023-01-26 9:13 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-01-26 9:13 fcontact at cuveland dot de [this message] 2023-01-26 9:51 ` [Bug libstdc++/108554] " redi at gcc dot gnu.org 2023-01-26 9:56 ` fcontact at cuveland dot de 2023-01-26 10:11 ` redi at gcc dot gnu.org 2023-01-26 10:14 ` redi at gcc dot gnu.org 2023-01-26 13:38 ` cvs-commit at gcc dot gnu.org 2023-01-26 13:41 ` [Bug libstdc++/108554] [12 Regression] " redi at gcc dot gnu.org 2023-01-27 15:43 ` cvs-commit at gcc dot gnu.org 2023-03-28 23:35 ` cvs-commit at gcc dot gnu.org 2023-03-28 23:35 ` redi at gcc dot gnu.org
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bug-108554-4@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).