https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115968
Bug ID: 115968
Summary: g++ 12 and above incorrectly optimize the code with
Eigen (-O2 or -O1)
Product: gcc
Version: 14.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: summersnow9403 at gmail dot com
Target Milestone: ---
The code example can be found on godbolt:
https://godbolt.org/z/qPs4zhb3j
The two functions test_eigen and test_eigen2 are expected to output the same
result. However, when compiled with gcc 12 and above versions with -O2, the
program prints all zeros for test_eigen. When compiled with gcc 12 and above
without -O2, or any versions of clang with -O2, the program behaves correctly.
