Performance regression in Gambatte with Pokemon Blue Japanese version

[pikhq]

I recently tried playing Pokemon Blue (Japanese version) using gambatte-libretro. When I reached the "load game/new game/settings" screen, the emulator slowed down to about 7fps. The same behavior does not occur with Gambatte 0.5.0, WIP2 on the same ROM. Likewise, it does not occur with the US Pokemon Blue ROM, on either version. My system is an AMD Phenom II X3 710, clocked at 2.6 GHz. I am running Debian, x86_64, and using a git checkout I built retroarch and gambatte-libretro. The ROM's md5sum is c1adf0a77809ac91d905a4828888a2f0.