[Issue 7157] Optimiser is O(n^2) w.r.t. function length

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=7157

--- Comment #13 from Walter Bright <bugzilla at digitalmars.com> ---
Partial fix: https://github.com/dlang/dmd/pull/6356

--