https://bugs.winehq.org/show_bug.cgi?id=38558
--- Comment #12 from katsunori.kumatani@gmail.com --- I've tested the new patch, and it works fine without the performance degradation of the former (I also added comments to explain why).
Feel free to submit the patch for me or even under your name, if doing otherwise requires some hurdles I have to go through (I've never submitted a patch before FWIW). I don't mind and it's pretty trivial / you found it anyway, would be good to have the bug fixed. Thanks again Jason. :)