[PATCH] D68408: [InstCombine] Negator - sink sinkable negations

Wed Oct 16 02:21:08 PDT 2019

lebedev.ri added a comment.

In D68408#1710214 <https://reviews.llvm.org/D68408#1710214>, @efriedma wrote:

> > If that doesn't happen, then they are 'trivially' dead and deleted.
>
> Deleted where, exactly?  If you're expecting the instcombine main loop to delete them, you'll force instcombine into an infinite loop, I think.

Hmm, they are not added to the instcombine's worklist unless we succeed in negating
the entire tree, and this passes test-suite with no infinite looping.

You are saying that we should instead DCE instructions in *our* worklist if we fail, correct?

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D68408/new/

https://reviews.llvm.org/D68408