tree c78a15d3a79646d2f6cccb9dc11d429d176f7d04
parent 382ffde1a121eb6828c24272c01d48e0830406c2
author Simon Pilgrim <llvm-dev@redking.me.uk> 1555608189 +0000
committer Simon Pilgrim <llvm-dev@redking.me.uk> 1555608189 +0000

[X86] combineVectorTruncationWithPACKUS - remove split/concatenation of mask

combineVectorTruncationWithPACKUS is currently splitting the upper bit bit masking into 128-bit subregs and then concatenating them back together.

This was originally done to avoid regressions that caused existing subregs to be concatenated to the larger type just for the AND masking before being extracted again. This was fixed by @spatel (notably rL303997 and rL347356).

This also lets SimplifyDemandedBits do some further improvements before it hits the recursive depth limit.

My only annoyance with this is that we were broadcasting some xmm masks but we seem to have lost them by moving to ymm - but that's a known issue as the logic in lowerBuildVectorAsBroadcast isn't great.

Differential Revision: https://reviews.llvm.org/D60375#inline-539623

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358692 91177308-0d34-0410-b5e6-96231b3b80d8