swift

e63632fd - [DebugInfo][SIL] Introduce the 'implicit' attribute for debug variable

[DebugInfo][SIL] Introduce the 'implicit' attribute for debug variable Debug variables that are marked 'implicit' on its `debug_value` instruction mean that they were generated by compiler. Optimizers are free to remove them (if it becomes a dead code, for instance) even in -Onone. Since they are barely used by users and keeping them might lead to incorrect IRGen results.