[PATCH] D111066: Disable "[SCEV] Prove implications of different type via truncation"

Max Kazantsev via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon Oct 4 22:52:04 PDT 2021


mkazantsev requested changes to this revision.
mkazantsev added a comment.
This revision now requires changes to proceed.

This patch is one year old. It is extremely surprising that you are trying to disable it rather than find the root cause.

I don't believe this is infinite recursion. Before all, infinite recursion should end up with stack overflow and not timeout. I can believe there is some exponential explosion happening, but in this case you need to find how exactly it happens and fix the acutal reason. The fact that this patch triggers something very slow doesn't convince me that this patch is guilty, and this test doesn't allow to figure it out easily.

Could you please check (at least, but not limited to):

- Do we end up creating some HUGE SCEVs in your test?
- Do we end up making the same implication query millions of times?
- Do we end up walking huge dom trees for execution of some queries?

Before we decide to switch something off, I want to know why exactly.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D111066/new/

https://reviews.llvm.org/D111066



More information about the llvm-commits mailing list