[PATCH] D21291: [SimplifyCFG] Range reduce switches

[James Molloy via llvm-commits]

jmolloy updated this revision to Diff 65900.
jmolloy added a comment.

Hi Hans,

I do agree with you. I think that the major reason I moved from SimplifyCFG to SDAGBuilder was that, because we were inserting new CFG edges, we didn't want to do this unless we could be *sure* that a dense switch lowering was used.

However now we've used the rotate trick, the inserted code is so tiny that we don't have to be so conservative. So I think it's OK to replicate the density heuristic in SimplifyCFG and that's what I've done.

I hope this is now more acceptable to you? :)

Cheers,

James


Repository:
  rL LLVM

https://reviews.llvm.org/D21291

Files:
  lib/Transforms/Utils/SimplifyCFG.cpp
  test/Transforms/SimplifyCFG/rangereduce.ll

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