1d9dcca9e3
This is primarily to avoid trailing unit dims: ``` %1 = vector.create_mask %c1, %dim_0, %c1, %c1 : vector<1x4x1x1xi1> %2 = vector.shape_cast %1 : vector<1x4x1x1xi1> to vector<1x4xi1> ``` becomes: ``` %1 = vector.create_mask %c1, %dim_0 : vector<1x4xi1> ``` Differential Revision: https://reviews.llvm.org/D158111