Erik Eckstein b8e348ce4a SIL: fix some problems in findJointPostDominatingSet ...

1. dead-end blocks (= blocks which eventually end up in an unreachable):

We cannot just ignore all dead-end blocks. This causes crashes for some corner cases (see the "infinite_loop_and_unreachable" test case). Instead just handle the common case of a simple single dead-end block - like we do in DestroyHoisting.
For other (more complex) dead-end control flows, the analysis is not incorrect. In worst case we end up inserting a not-needed destroy instruction.

2. sortUnique

I restructured the code a bit so that sortUnique is not needed anymore. sortUnique on pointer arrays can result in non-deterministic behavior.

3. lower_bound

Also, using lower_bound on a vector is not good in this function, because it can result in quadratic behavior. Though, in practice, there are only very few elements in the vector. So it's more a theoretical thing.

The restructuring made the code a bit simpler, e.g. beside the worklist, no other vectors are needed anymore.

2021-02-02 10:20:35 +01:00

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