[PATCH] D119854: [SimplifyCFG][PhaseOrdering] Defer lowering switch into an integer range comparison and branch until after at least the IPSCCP

[Nikita Popov via Phabricator via llvm-commits]

nikic accepted this revision.
nikic added a comment.
This revision is now accepted and ready to land.

LGTM



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Comment at: llvm/include/llvm/Transforms/Utils/SimplifyCFGOptions.h:26
   bool ForwardSwitchCondToPhi = false;
+  bool ConvertSwitchRangeToICmp = false;
   bool ConvertSwitchToLookupTable = false;
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lebedev.ri wrote:
> nikic wrote:
> > As we want to disable this essentially only for the first SimplifyCFG run, may make the default true?
> I acknowledge that this is a tricky question,
> but opting-into something lossy seems better
> than ensuring that we opt-out everywhere,
> so i've gone with that.
> I don't think there is The Right choice here.
I think this is mostly a pragmatic choice (if a new SimplifyCFG run gets added, which behavior should it most likely have?) but I don't care strongly about it...


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https://reviews.llvm.org/D119854