When I want to use a high optimization level with IAR 8.21 and SSP 1.4.0 the compilation of tx_thread_schedule.c stops with the above error message.
At the moment I use the workaround to set the optimization level for this file individually to "none" but there must be global solution.
Neither on the IAR.website nor here on renesasrulz I found any hint what causes this error message and where and how it can be solved.