It's not usual to ad Potassium Bromide to film developers, it's unlikely to help much and you can print through any increased based fog. With papers adding bromide reduces the sensitivity meaning you need increased exposure.

In addition some film developers are very sensitive to increased bromide levels, it inhibits the action of Metol, it may well have a similar effect on the p-Aminophenol in Rodinal, but would have far less effect with Rodinal Special which is a PQ developer. Phenidone is restistant to much higher levels of Bromide.

Ian