[Mlir-commits] [mlir] [mlir] Avoid rewriting unreachable blocks in the greedy driver (PR #225814)

[Mehdi Amini]

================

----------------
joker-eph wrote:

Are you asking about the use case for the pull requests entirely, or something specific about this comment? 

The motivating case doesn’t require reconnecting dead code. Folding a constant conditional branch can disconnect a loop while its operations are still queued. Subsequent simplifications in that unreachable loop can produce self-referential SSA uses, causing crashes or repeated re-enqueuing.

Eager block deletion after each completed rewrite is an alternative for the region driver, but it raises a separate scope question for the explicit-operation driver, see the thread discussion with Matthias above.

https://github.com/llvm/llvm-project/pull/225814