[X86] Add broadcast patterns that allow a scalar_to_vector between the broadcast and the load.

We already have these patterns for AVX512VL, but not AVX1 or 2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315382 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed