[llvm-branch-commits] [CodeGen] Limit number of analyzed predecessors (PR #142584)

[Alexis Engelke via llvm-branch-commits]

https://github.com/aengelke created https://github.com/llvm/llvm-project/pull/142584

MachineBlockPlacement has quadratic runtime in the number of
predecessors: in some situation, for an edge, all predecessors of the
successor are considered.

Limit the number of considered predecessors to bound compile time for
large functions.