[llvm] [RFC] implement convergence control in MIR using SelectionDAG (PR #71785)

[Sameer Sahasrabuddhe via llvm-commits]

https://github.com/ssahasra commented:

@arsenm do you see any potential pitfalls in how the glue node is being passed around? The glue is needed only on intrinsics, and there are a couple of FIXME comments about the possibility of some intrinsic having multiple glue nodes. Also, at one point, SelectNodeTo() loses the glue node, so this change first stashes the node, then calls SelectNodeTo(), and then adds the glue node back with MorphNodeTo().

https://github.com/llvm/llvm-project/pull/71785