[llvm] [IR] BlockAddress doesn't use BasicBlock (PR #200772)

[Alexis Engelke via llvm-commits]

aengelke wrote:

> Is this actually redundant though? The docs only talk about blockaddress, but isn't the use list order for BBs also relevant because it determines the order of the predecessors iterator?

The use list order of a basic block is also be specifiable inside the function with the normal uselistorder directive. This is tested, e.g., by test/Assembler/uselistorder.ll. From what I understand, the uselistorder_bb directive is only required so that it can specify the uselist outside of a function, where a special syntax is needed to identify the block.

> Regarding uselistorder_bb, note that we also have USELIST_CODE_BB in bitcode.

This indeed seems to be orthogonal.

I do get the impression, though, that uselists aren't particularly well tested and I can't say that I fully understand how our readers/writers work.

https://github.com/llvm/llvm-project/pull/200772