[PATCH] D89586: [SCEV] Use the number of steps of an IV to clamp max BTC (WIP).

[Florian Hahn via Phabricator via llvm-commits]

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As discussed in D89381 <https://reviews.llvm.org/D89381>, we can use the range of an non-wrapping IV to
clamp down the max BTC in some cases.

This impacts a few other test cases that I still need to update and it
seems in some cases the new bound is more precise than the exact exit
count, which I still need to investigate. I just wanted to share this
early.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D89586

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll
  llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-limit-by-wrapping.ll
  llvm/test/Analysis/ScalarEvolution/trip-count.ll

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