552c6c2 removed support for promoting VLAs to constant arrays when the bounds
isn't an ICE, since this can result in miscompiling a conforming program that
assumes that the array is a VLA. Promoting VLAs for fields is still supported,
since clang doesn't support VLAs in fields, so no conforming program could have
a field VLA.
This change is really disruptive, so this commit carves out two more cases
where we promote VLAs which can't miscompile a conforming program:
- When the VLA appears in an ivar -- this seems like a corollary to the field thing
- When the VLA has an initializer -- VLAs can't have an initializer
Differential revision: https://reviews.llvm.org/D90871
Erik Pilkington