[PATCH] D35918: [GVNHoist] Factor out reachability to search for anticipable instructions quickly

[Aditya Kumar via Phabricator via llvm-commits]

hiraditya updated this revision to Diff 110647.
hiraditya added a comment.

Based on suggestions from @dberlin, I have updated the patch:

1. Compute iterated post-dominance frontiers
2. Iterate on post-dominator tree to insert CHIargs more efficiently

The time complexity would now be: O(duplicate-values * N) where N = nodes in the CFG. For each duplicate values the algorithm finds their control-dependence by computing the iterated post-dominance frontier and then inserts CHI args to track anticipability.


https://reviews.llvm.org/D35918

Files:
  lib/Transforms/Scalar/GVNHoist.cpp
  test/Transforms/GVNHoist/hoist-more-than-two-branches.ll
  test/Transforms/GVNHoist/hoist-mssa.ll
  test/Transforms/GVNHoist/hoist-newgvn.ll
  test/Transforms/GVNHoist/hoist-pr20242.ll
  test/Transforms/GVNHoist/hoist-pr28933.ll
  test/Transforms/GVNHoist/hoist-recursive-geps.ll
  test/Transforms/GVNHoist/hoist.ll
  test/Transforms/GVNHoist/infinite-loop-direct.ll
  test/Transforms/GVNHoist/infinite-loop-indirect.ll

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