[llvm] [SelectionDAG] Improve wide integer squaring (PR #226403)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,288 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
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arsenm wrote:

Old version 

https://github.com/llvm/llvm-project/pull/226403