https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90329
--- Comment #18 from Janne Blomqvist <jb at gcc dot gnu.org> --- (In reply to Thomas Koenig from comment #15) > Since we applied the fix for PR 87689 to gcc 7, gcc 8 and gcc 9, > I would suggest that we make -fno-optimize-sibling-calls > the default on these branches. Maintaining binary compatibility > (even if it is bug compatibility) with existing packages is > something we should strive for, especially with such > important software packages as BLAS and LAPACK. +1. Especially considering Steve's benchmark suggesting there's practically no difference, although there may of course be other code where sibling call optimization makes a difference. > For current trunk, I would recommend keeping the current > hehavior and contact the LAPACK maintainers to a) give them > a heads-up for this problem, and b) a year to work out > the problem. Yes. Closer to GCC 10, we can revisit this. I suspect we'll have to make -fno-optimize-sibling-calls the default for GCC 10 as well; while we might be able to help LAPACK maintainers fix LAPACKE there's in this timeframe there's certainly a lot of other code out there with custom C-Fortran interfaces which might be affected.