https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79593
--- Comment #13 from Katsunori Kumatani <katsunori.kumatani at gmail dot com> --- Ah sorry! I skimmed through that as I thought it was talking about the patch's fld (that it improved). Thanks, it's good to know the cause at least :) I hope it makes it easier to improve if needed to pull from GCC 5. If you have the time, would you point me to the source file that triggers this optimization (and I assume is not in GCC 5), or is that a question for the "tree experts"? Meaning, difficult to understand where, since GCC is a complex project and quite intimidating for those unfamiliar with it like me :)
