Commit Graph

3 Commits

Author SHA1 Message Date
Philip Reames e64ed3c8df [test] autogen a couple of additional tests 2021-10-05 18:58:08 -07:00
Sanjay Patel 9d6d24c250 [JumpThreading][VectorUtils] avoid infinite loop on unreachable IR
https://llvm.org/PR48362

It's possible that we could stub this out sooner somewhere
within JumpThreading, but I'm not sure how to do that, and
then we would still have potential danger in other callers.

I can't find a way to trigger this using 'instsimplify',
however, because that already has a bailout on unreachable
blocks.
2020-12-02 13:39:33 -05:00
Wei Mi 55a68a2400 [JumpThreading] Stop searching predecessor when the current bb is in a
unreachable loop.

updatePredecessorProfileMetadata in jumpthreading tries to find the
first dominating predecessor block for a PHI value by searching upwards
the predecessor block chain.

But jumpthreading may see some temporary IR state which contains
unreachable bb not being cleaned up. If an unreachable loop happens to
be on the predecessor block chain, keeping chasing the predecessor
block will run into an infinite loop.

The patch fixes it.

Differential Revision: https://reviews.llvm.org/D65310

llvm-svn: 367154
2019-07-26 20:59:22 +00:00