[Vectorize] Migrate away from PointerUnion::dyn_cast (NFC)#125159

kazutakahirata merged 1 commit intollvm:mainllvm/llvm-project:mainfrom

kazutakahirata:cleanup_001_PointerUnion_llvm_SLPkazutakahirata/llvm-project:cleanup_001_PointerUnion_llvm_SLPCopy head branch name to clipboard