When building a Sparse*Sparse product which is later decomposed it can be advantageous not to prune numerical zeros, so that the symbolical decomposition can be reused. Moreover it might be possible to 'recompute' a Sparse*Sparse product where the structure did not change thus no overhead for reallocation would arise.
The first wish is fixed by change f4c8f74154f9. I'll add a new entry for the second wish.
-- GitLab Migration Automatic Message -- This bug has been migrated to gitlab.com's GitLab instance and has been closed from further activity. You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.com/libeigen/eigen/issues/284.