[PATCH] D102615: [LoopDeletion] Break backedge if we can prove that the loop is exited on 1st iteration (try 3)

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev added a comment.

> This is surprising to me -- why does this require changes to InstSimplify?

InstSimplify does not provide public API for this:

  const SCEV *LHSS = getSCEVOnFirstIteration(LHS, L, SE, FirstIterSCEV);
  const SCEV *RHSS = getSCEVOnFirstIteration(RHS, L, SE, FirstIterSCEV);
  S = SE.getAddExpr(LHSS, RHSS);

It has `SimplifyAddInst` that works with custom arguments, but it's currently static within the cpp file. I'd need to expose all of them. At least this, maybe more.


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https://reviews.llvm.org/D102615