forked from OSchip/llvm-project
4a699ae9c6
LoopSimplifyCFG may process loops that are not in
loop-simplify/canonical form. For loops not in canonical form, exit
blocks may be reachable from non-loop blocks and we cannot consider them
as dead if they only are not reachable from the loop itself.
Unfortunately the smallest test I could come up with requires running
multiple passes:
-passes='loop-mssa(loop-instsimplify,loop-simplifycfg,simple-loop-unswitch)'
The reason is that loops are canonicalized at the beginning of loop
pipelines, so a later transform has to break canonical form in a way
that breaks LoopSimplifyCFG's dead-exit analysis.
Alternatively we could try to require all loop passes to maintain
canonical form. That in turn would also require additional verification.
Fixes #54023, #49931.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D121925
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| .. | ||
| constant-fold-branch.ll | ||
| handle_dead_exits.ll | ||
| irreducible_cfg.ll | ||
| lcssa.ll | ||
| live_block_marking.ll | ||
| loop-not-in-simplify-form.ll | ||
| merge-header.ll | ||
| mssa_update.ll | ||
| phi_with_duplicating_inputs.ll | ||
| pr39783.ll | ||
| scev.ll | ||
| update_parents.ll | ||