[llvm] [SelectionDAG] Use getVectorElementPointer in DAGCombiner::replaceStoreOfInsertLoad. (PR #74249)

[John Regehr via llvm-commits]

regehr wrote:

this looks great to me, but I am not very knowledgeable about this part of the code base! it does look like the right answer to the problem.

https://github.com/llvm/llvm-project/pull/74249