https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84357
Bug ID: 84357 Summary: Incorrect 'foo' is used uninitialized with -O3 Product: gcc Version: 8.0.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: janisozaur+gcc at gmail dot com Target Milestone: --- Created attachment 43402 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43402&action=edit reproducer Compile attachment with `-O3 -Werror -Wuninitialized`, tested with GCC 8.0.1 20180211 on wandbox: https://wandbox.org/permlink/jW0p9vIwIwHOEmEb prog.c: In function 'foo': prog.c:24:14: error: 'i' is used uninitialized in this function [-Werror=uninitialized] for (int i = 0; i < COUNT; i++) ^ cc1: all warnings being treated as errors