Track the identity of each string literal object produced by evaluation
with a global version number. Accept comparisons between literals of the
same version, and between literals of different versions that cannot
possibly be placed in overlapping storage. Treat the remaining
comparisons as non-constant.
---------
Co-authored-by: Timm Baeder <tbaeder@redhat.com>
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
This requires adding a new opcode for PointerToBoolean casts, since we
otherwise emit too many diagnostics. But that fixes an older problem
when casting weak pointers to bool.
