[llvm] [EarlyCSE] merge consecutive bitfield accesses in case of pointers (PR #76053)

[Nikita Popov via llvm-commits]

https://github.com/nikic requested changes to this pull request.

This optimization is not legal for the example as written. `@b` might be stored inside `@b`, in which case the store to `%0` will change the value returned by the next load from `@b`.

You need additional aliasing information (e.g. from TBAA) to allow this transform (in which case it will likely already be performed without additional changes).

https://github.com/llvm/llvm-project/pull/76053