[PATCH] D106851: [SCEV] Add two tests showing the bug in SCEV getAddExpr

[Serguei Katkov via Phabricator via llvm-commits]

skatkov created this revision.
skatkov added reviewers: reames, nikic, efriedma, fhahn, mkazantsev.
Herald added a subscriber: javed.absar.
skatkov requested review of this revision.
Herald added a project: LLVM.

getAddExpr utility uses computed flags from AddRec plus loop invariants
in AddRec.Start + loop invariants basing on the an assumption that
0th iteration of the loop exists. However the loop might be dead
(runtime or compile time), in this case the propagation of the flag becomes
invalid.

One of the test shows the incorrect behavior of IndVarSimplify pass
in case of nested loops.
The second test shows incorrect SCEV computation of sibling loops.

In both cases the right loop is runtime dead and incorrect SCEV is computes
for alive left loop.


https://reviews.llvm.org/D106851

Files:
  llvm/test/Analysis/ScalarEvolution/nuw-add-nested-loops.ll
  llvm/test/Analysis/ScalarEvolution/nuw-add-sibling-loops.ll

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