https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80038
--- Comment #14 from Xi Ruoyao <ryxi at stu dot xidian.edu.cn> --- (In reply to Florent Hivert from comment #13) > I've not yet been able to find a small example that shows the regression due > to GCC5 ICE. In particular, I'm not sure the problem mentioned by Fournival > is not due to a bug in my code (See my question of > http://stackoverflow.com/questions/42816920/data-race-in-cilk-home-made- > reducer) Although I don't understand all the code in the Github repo, but GCC 6 indeed moved the temporary construction (initialization) and destruction code to the parent, and violated cilkplus spec. So it's very sure this is a regression of GCC.