This is enabled by default. Drop explicit uses in preparation for
removing the option.
Also drop RUN lines that are now the same (typically modulo a
-verify-memoryssa option).
As mentioned in
http://lists.llvm.org/pipermail/llvm-dev/2020-July/143395.html,
loop-unswitch has not been ported to the NPM. Instead people are using
simple-loop-unswitch.
Pin all tests in Transforms/LoopUnswitch to legacy PM and replace all
other uses of loop-unswitch with simple-loop-unswitch.
One test that didn't fit into the above was
2014-06-21-congruent-constant.ll which seems to only pass with
loop-unswitch. That is also pinned to legacy PM.
Now all tests containing "-loop-unswitch" anywhere in the test succeed with
NPM turned on by default.
Reviewed By: ychen
Differential Revision: https://reviews.llvm.org/D85360
Summary:
When inserting a new Def, MemorySSA may be have non-minimal number of Phis.
While inserting, the walk to find the previous definition may cleanup minimal Phis.
When the last definition is trivial to obtain, we do not cache it.
It is possible while getting the previous definition for a Def to get two different answers:
- one that was straight-forward to find when walking the first path (a trivial phi in this case), and
- another that follows a cleanup of the trivial phi, it determines it may need additional Phi nodes, it inserts them and returns a new phi in the same position as the former trivial one.
While the Phis added for the second path are all redundant, they are not complete (the walk is only done upwards), and they are not properly cleaned up afterwards.
A way to fix this problem is to cache the straight-forward answer we got on the first walk.
The caching is only kept for the duration of a getPreviousDef call, and for Phis we use TrackingVH, so removing the trivial phi will lead to replacing it with the next dominating phi in the cache.
Resolves PR40749.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60634
llvm-svn: 358313
Nikita Popov