Function rustc_mir_transform::jump_threading::loop_headers

fn loop_headers(body: &Body<'_>) -> BitSet<BasicBlock>

Compute the set of loop headers in the given body. We define a loop header as a block which has at least a predecessor which it dominates. This definition is only correct for reducible CFGs. But if the CFG is already irreducible, there is no point in trying much harder. is already irreducible.