[llvm] [JumpThreading] Fix lifetime markers when alloca requires SSA renaming (PR #188147)

[Nikita Popov via llvm-commits]

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nikic wrote:

Please use update_test_checks.py.

I think it would also be good to have a variant of the test case where the lifetime markers *can* be preserved because they are all dominated.

https://github.com/llvm/llvm-project/pull/188147