Explore vector dialect transformation options

[Kuigesi]

Vector dialect have options VectorTransformOptions to control the lowering of different vector ops(vector.contract, vector.multi_reduction, vector.transpose, etc.).
For example, a vector.contract representing a m-n-k matrix mutiply can be lowered to either a naive loop implementation, or to vector.matmul (finally to llvm.matrix.multiply), or to vector.outerproduct.
It may be worthwhile to explore these lowering options to obtain better performance.