The too long with yielding error has a legitimate purpose, but many programs have a valid reason to want to run a loop as quickly as possible, and in previous versions of CC, this error could be avoided by calling sleep(0) but in 1.80 pr1 it seems that it will eventually throw a yielding error after several minutes using this method.

Can you post at example program demonstrating this behaviour? I can't think of any change which would cause this.