[Bug tree-optimization/126735] New: [16/17 Regression] -Wmaybe-uninitialized false positive under -fsanitize=thread -O1

"gnu.ojxq8 at dralias dot com via Gcc-bugs" <[email protected]> Sat, 08 Aug 2026 13:30:28 +0000

Newsgroups	gmane.comp.gcc.bugs
Message-ID	<[email protected]/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126735

            Bug ID: 126735
           Summary: [16/17 Regression]  -Wmaybe-uninitialized false
                    positive under -fsanitize=thread -O1
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gnu.ojxq8 at dralias dot com
  Target Milestone: ---

flags to repro:

-O1 -fsanitize=thread -Wall -Wextra -Wmaybe-uninitialized -std=c++11

code to repro:

#include <map>
std::map<int, int> CreateMap();
void ReproduceMapCopyWarning() {
    auto map_result = CreateMap();
    for (const auto& map_entry : {map_result, map_result});
}


https://godbolt.org/z/bo7Yd1Ecq