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When an ``Instruction`` is deleted, its debug uses change to ``undef``. This is
-a loss of debug info: the value of a one or more source variables becomes
+a loss of debug info: the value of one or more source variables becomes
unavailable, starting with the ``llvm.dbg.value(undef, ...)``. When there is no
way to reconstitute the value of the lost instruction, this is the best
possible outcome. However, it's often possible to do better: