commit 200d59f918b7df9672f4872a3e4be2eaf3433b65
author Simon Pilgrim <llvm-dev@redking.me.uk> Sat Oct 19 13:18:02 2019 +0000
committer Simon Pilgrim <llvm-dev@redking.me.uk> Sat Oct 19 13:18:02 2019 +0000
tree 3fe25baba73191fb04554c7cc4c06d425180d917
parent 39580be1ee0c1ca9d532985d8f0fa27afab6d453

[X86][SSE] lowerV16I8Shuffle - tryToWidenViaDuplication - undef unpack args

tryToWidenViaDuplication lowers using the shuffle_v8i16(unpack_v16i8(shuffle_v8i16(x),shuffle_v8i16(x))) pattern, but the unpack only needs the even/odd 16i8 args if the original v16i8 shuffle mask references the even/odd elements - which isn't true for many extension style shuffles.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375342 91177308-0d34-0410-b5e6-96231b3b80d8