The DAG maintains a chain of MemDGNodes that links together all the
nodes that may touch memroy.
Whenever a new instruction gets created we need to make sure that this
chain gets updated. If the new instruction touches memory then its
corresponding MemDGNode should be inserted into the chain.
This patch adds the callback registration logic in the DAG's constructor
and the corresponding deregistration logic in the destructor. It also
implements the code that makes sure that SchedBundle and DGNodes can be
safely destroyed in any order.
This is a refactoring patch that moves the callback registration for
getting notified about new instructions from the scheduler to the DAG.
This makes sense from a design and testing point of view:
- the DAG should not rely on the scheduler for getting notified
- the notifiers don't need to be public
- it's easier to test the notifiers directly from within the DAG unit
tests
This patch implements a ready-list-based scheduler that operates on
DependencyGraph.
It is used by the sandbox vectorizer to test the legality of vectorizing
a group of instrs.
SchedBundle is a helper container, containing all DGNodes that
correspond to the instructions that we are attempting to schedule with
trySchedule(Instrs).
This patch implements the UnscheduledSuccs counter in DGNode. It counts
the number of unscheduled successors and is used by the scheduler to
determine when a node is ready.
This patch moves:
- Utils::isStackSaveOrRestoreIntrinsic()
- Utils::isMemIntrinsic()
- Utils::isMemDepCandidate()
to DGNode because they no longer require LLVM IR access and are used
only by the DAG.
This patch implements the MemDGNode class for DAG nodes that are
candidates
for memory dependencies. These nodes form a chain that is accessible by
`getPrevNode()` and `getNextNode()`.
It also implements a builder class that creates MemDGNode intervals from
Instructions.
