[Compatibility] Some old version of bitcode cannot be parsed since 18.0.0

[uaex]

I found some changes in LLVM version 18.0.0:

The constant expression variants of the following instructions have been removed:
and
or

Some old version of bitcode cannot be parsed. Can we provide compatibility support?

Error Message:
Value referenced by initializer is an unsupported constant expression of type or

[nikic]

Please provide the problematic bitcode. Though as the expression is part of an initializer, the answer is probably "no".

[RIscRIpt]

If I understand correctly, this is related to #139245. If you take bug.ll from #139245 and try to assemble it using LLVM19 you can observe relevant error message:

bug.ll:22:104: error: or constexprs are no longer supported

According to LLVM Developer Policy there are no promises made about compatibility of textual format:

The textual format is not backwards compatible. We don’t change it too often, but there are no specific promises.

For this reason, I think we can close this issue.