[PATCH] D11115: [LSR] don't attempt to promote ephemeral values to indvars

[Jingyue Wu]

jingyue created this revision.
jingyue added reviewers: atrick, hfinkel.
jingyue added a subscriber: llvm-commits.

This at least saves compile time. I also encountered a case where
ephemeral values affect whether other variables are promoted, causing
performance issues. It may be a bug in LSR, but I didn't manage to
reduce it yet. Anyhow, I believe it's in general not worth considering
ephemeral values in LSR.

http://reviews.llvm.org/D11115

Files:
  include/llvm/Analysis/IVUsers.h
  lib/Analysis/IVUsers.cpp
  test/Transforms/LoopStrengthReduce/ephemeral.ll

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