[PATCH] D56057: [X86] Individually simplify both operands of PMULDQ/PMULUDQ using the other entry point of SimplifyDemandedBits that allows the one use check of the root node to be suppressed.

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added a comment.

I'm sorry about that, I focussed on checking the earlier (and by looks of it easier) test cases - SimplifyDemandedBits patches tend to cause a lot of changes with a lot of interesting cases where it can throw away a lot of code. So I was expecting some changes like that and didn't look at them more critically.

The splitting version of SimplifyDemandedBits now scares me - I think the issue is that the TLO.Old.hasOneUse() code doesn't take into account that it might have gone through several other ops that had multiple uses but I haven't checked this yet.


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  rL LLVM

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  https://reviews.llvm.org/D56057/new/

https://reviews.llvm.org/D56057