[llvm] [SelectionDAG] Wire up -gen-sdnode-info TableGen backend (PR #125358)

[Min-Yih Hsu via llvm-commits]

mshockwave wrote:

> > Have we ever verified normal (non-target) SDNodes using similar logics you put in SDNodeInfo::verifyNode?
> 
> This `verifySDNode` checks `BUILD_PAIR` and `BUILD_VECTOR`, and there are also some ad-hoc asserts in `SelectionDAG::getNode()`, [example](https://github.com/llvm/llvm-project/blob/b7c8271601461e02fb567d6cd175fe20e123d78a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp#L6282).

Right, but I'm curious whether we should call SDNodeInfo::verifyNode on non-target nodes too. Because I think there is no mechanism to prevent users from inserting chain / glue operands with the wrong order in non-target nodes.

https://github.com/llvm/llvm-project/pull/125358