[X86][AVX] concat_vectors(scalar_to_vector(x),scalar_to_vector(x)) --> broadcast(x)

For AVX1, limit this to i32/f32/i64/f64 loading cases only.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354730 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed