Support for the legacy pass manager in ArgPromotion causes
complications in D125485. As the legacy pass manager for middle-end
optimizations is unsupported, drop ArgPromotion from the legacy
pipeline, rather than introducing additional complexity to deal
with it.
Differential Revision: https://reviews.llvm.org/D128536
In addition to the self-recursion check, also check whether there
is more than one node in the SCC, which implies that there is a
larger cycle. I believe checking SCC structure (rather than
something like norecurse) is the right thing to do here, because
this is specifically about preventing infinite loops over the SCC.
Fixes https://github.com/llvm/llvm-project/issues/42028.
Differential Revision: https://reviews.llvm.org/D119418
Nikita Popov