Validate voltage/power domain goal overview:

To check your power intent for level shifters, isolation logic, retention registers and other low power cell types, enter a SpyGlass sgdc file, or a CPF file, or a UPF file.

Power_verification_RTL checks the intent at the RTL level.  Even if you have not added low power cell types to the RTL, SpyGlass will check that the intent is correct and complete.
