[llvm] [SelectionDAG] Folding ZERO-EXTEND/SIGN_EXTEND poison to Poison value in getNode (PR #122741)

[zhijian lin via llvm-commits]

diggerlin wrote:

I created a patch https://github.com/llvm/llvm-project/pull/136636 to fix the test cases which cause the buildbot fail 



https://github.com/llvm/llvm-project/pull/122741