With the option -sil-print-debuginfo the printing of debug locations and scopes can be enabled.
I made the default for the option “false”, because in 99% of the time I don’t need the debug info in the printed SIL and I prefer better readability.
For details see the comment in ConditionForwarding.cpp.
This optimization pass helps to optimize loops iterating over closed ranges, e.g. for i in 0...n { }