Commit Graph

2 Commits

Author SHA1 Message Date
Fedor Sergeev 194a407bda [New PM][IRCE] port of Inductive Range Check Elimination pass to the new pass manager
There are two nontrivial details here:
* Loop structure update interface is quite different with new pass manager,
  so the code to add new loops was factored out

* BranchProbabilityInfo is not a loop analysis, so it can not be just getResult'ed from
  within the loop pass. It cant even be queried through getCachedResult as LoopCanonicalization
  sequence (e.g. LoopSimplify) might invalidate BPI results.

  Complete solution for BPI will likely take some time to discuss and figure out,
  so for now this was partially solved by making BPI optional in IRCE
  (skipping a couple of profitability checks if it is absent).

Most of the IRCE tests got their corresponding new-pass-manager variant enabled.
Only two of them depend on BPI, both marked with TODO, to be turned on when BPI
starts being available for loop passes.

Reviewers: chandlerc, mkazantsev, sanjoy, asbirlea
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D43795

llvm-svn: 327619
2018-03-15 11:01:19 +00:00
Max Kazantsev f80ffa1a78 [IRCE] Fix corner case with Start = INT_MAX
When iterating through loop

  for (int i = INT_MAX; i > 0; i--)

We fail to generate the pre-loop for it. It happens because we use the
overflown value in a comparison predicate when identifying whether or not
we need it.

In old logic, we used SLE predicate against Greatest value which exceeds all
seen values of the IV and might be overflown. Now we use the GreatestSeen
value of this IV with SLT predicate.

Also added a test that ensures that a pre-loop is generated for such loops.

Differential Revision: https://reviews.llvm.org/D35347

llvm-svn: 308001
2017-07-14 06:35:03 +00:00