[AVX-512] Improve lowering of sign_extend of v4i1 to v4i32 and v2i1 to v2i64 when avx512vl is available, but not avx512dq.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291746 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed