[PATCH] D37762: [InstCombine] Remove single use restriction from InstCombine's explicit sinking code.

[Aditya Kumar via Phabricator via llvm-commits]

hiraditya added a comment.

In https://reviews.llvm.org/D37762#868790, @davide wrote:

> I think what matters in this case is the {post}dominance relation between the block of the DEF and the block(s) [potentially > 1] of the USEs.


Agreed with this.

> Doing this xform when all the uses are in the same block, is, correct, but restrictive. So, I think your logic is fine, but this makes me still less convinced that we shouldn't use the dom to drive this analysis (and therefore should be a separate pass :)

I think GVNSink could be improved to do this. Also the current implementation in InstCombiner looks like a hack. We are sinking an instruction without appropriate cost model. Delaying execution of an instruction may not always be a good idea.


https://reviews.llvm.org/D37762