The 32-Bit Beta Version for Windows works. In detail:
- Tested today 2. July 2018
- 2018-06 Windows 10 Version 1803 for Intel based systems (KB4284848)
- pypy3-v6.0.0-win32.zip downloaded today from http://pypy.org/download.html
- PyCharm 2018.1.4 Professional Edition
I've unpacked the downloaded "pypy3-v6.0.0-win32.zip" to "C:\pypy3-v6.0.0-win32". No need to run any installer. I've created a new PyCharm-Project. Go to into the Menu "File" select "Settings". Then select "Project pane", click the Cog, click "Add ...", click "System Interpreter", click "..." on the top-right and navigate to "C:\pypy3-v6.0.0-win32\pypy3.exe".
PyCharm took a while to generate all skeletons. After that, everything runs as expected.
If you need more instructions on how to set new Python interpreter: Pycharm has a detailed instrucions.