[PATCH] D42407: [X86] Use ISD::SIGN_EXTEND instead of X86ISD::VSEXT for mask to xmm/ymm/zmm conversion

Simon Pilgrim via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Jan 23 07:48:52 PST 2018


RKSimon added a comment.

> I also had to add isel patterns because DAG combine blindly combines sign_extend+truncate to a smaller sign_extend which defeats what legalization was trying to do.

What's the fallout from instead altering DAGCombine to only do this with !LegalOperations || TLI.isOperationLegal ?


https://reviews.llvm.org/D42407





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