Getting a List of Registers Optimized Away by DC
There is no direct way to get a list of registers optimized away by
Design Compiler. A workaround is to get a list of all registers in the
design before compile by using
set pre_compile_regs [all_registers]
Then get a list of registers after compile by using
set post_compile_regs [all_registers]
Then you can find out which registers were optimized away by using
set lost_regs [remove_from_collection $pre_compile_regs $post_compile_regs]