[PATCH] D53201: [DAGCombiner] reduce insert+bitcast+extract vector ops to truncate (PR39016)

[Craig Topper via Phabricator via llvm-commits]

craig.topper added a comment.

FYI, the post legalize types DAG combine doesn’t run if all the types in the DAG were legal and nothing was changed by legalize types. So gating a combine on LegalTypes can really mean a transform doesn’t run until after vector op legalization(again the DAG combine after this doesn’t run if nothing changed) or LegalizeDAG.


https://reviews.llvm.org/D53201