[PATCH] D66052: [DAGCombiner] Add simple folds for SMULFIX/UMULFIX/SMULFIXSAT

Bjorn Pettersson via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Thu Aug 15 11:46:34 PDT 2019


bjope added a comment.

It seems like widening vector legalization for X86 can introduce fixed point multiplication of undef values. So that is one way that such operations could appear during ISel.

Multiplication with zero is probably more unlikely, and could potentially be handled by InstCombine. But I do not think it would hurt to do such folds in DAGCombiner.


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  https://reviews.llvm.org/D66052/new/

https://reviews.llvm.org/D66052





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