[PATCH] D88208: [SCEV] Prove implicaitons via AddRec start

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev created this revision.
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If we know that some predicate is true for AddRec and an invariant
(w.r.t. this AddRec's loop), this fact is, in particular, true on the first
iteration. We can try to prove the facts we need using the start value.

The motivating example is proving things like

  isImpliedCondOperands(>=, X, 0, {X,+,-1}, 0}


https://reviews.llvm.org/D88208

Files:
  llvm/include/llvm/Analysis/ScalarEvolution.h
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/unittests/Analysis/ScalarEvolutionTest.cpp

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