co_await and co_yield are represented by (classes derived from)
CoroutineSuspendExpr. That has a number of child nodes, not all of
which are used for code-generation. In particular the operand is
represented multiple times, and, like the problem with co_return
(55406) it must only be emitted in the CFG exactly once. The operand
also appears inside OpaqueValueExprs, but that's ok.
This adds a visitor for SuspendExprs to emit the required children in
the correct order. Note that this CFG is pre-coro xform. We don't
have initial or final suspend points.
Reviewed By: bruno
Differential Revision: https://reviews.llvm.org/D127236
CoreturnStmt needs to keep the operand value distinct from its use in
any return_value call, so that instantiation may rebuild the latter.
But it also needs to keep the operand value separate in the case of
calling return_void. Code generation checks the operand value form to
determine whether it is a distincte entity to the promise call. This
adds the same logic to CFG generation.
Reviewed By: bruno
Differential Revision: https://reviews.llvm.org/D126399
Nathan Sidwell