[llvm] [IRBuilder][ConstantFold] Fold constant for CreateInsertVector. (PR #116229)

[Nikita Popov via llvm-commits]

nikic wrote:

@HanKuanChen Make CreateIntrinsic go through FoldIntrinsic, which then folds this intrinsic (and others).

https://github.com/llvm/llvm-project/pull/116229