[llvm] [IR] Split vector.splice into vector.splice.left and vector.splice.right (PR #170796)

[Craig Topper via llvm-commits]

topperc wrote:

I found that C++20 adds std::shift_left and std::shift_right to <algorithm> for container ranges that matches the definitions of left and right used here.

https://github.com/llvm/llvm-project/pull/170796