llvm-svn: 157426

llvm-svn: 157425

llvm-svn: 157424

llvm-svn: 157020

llvm-svn: 157007

Introduce the basic strategy for register pressure scheduling.

1) Respect target limits at all times.

2) Indentify critical register classes (pressure sets).
   Track pressure within the scheduled region.
   Avoid increasing scheduled pressure for critical registers.

3) Avoid exceeding the max pressure of the region prior to scheduling.

Added logic for picking between the top and bottom ready Q's based on
regpressure heuristics.

Status: functional but needs to be asjusted to achieve good results.
llvm-svn: 157006

llvm-svn: 157005

llvm-svn: 157003

llvm-svn: 156576

llvm-svn: 156575

Prioritize the instruction that comes closest to keeping pressure
under the target's limit. Then prioritize instructions that avoid
increasing the max pressure in the scheduled region. The max pressure
heuristic is a tad aggressive. Later I'll fix it to consider the
unscheduled pressure as well.

WIP: This is mostly functional but untested and not likely to do much good yet.
llvm-svn: 156574

llvm-svn: 156573

llvm-svn: 156572

llvm-svn: 156571

llvm-svn: 155486

llvm-svn: 155458

llvm-svn: 155457

The DAG builder is a convenient place to do it. Hopefully this is more
efficient than a separate traversal over the same region.

llvm-svn: 155456

llvm-svn: 153827

llvm-svn: 153161

llvm-svn: 153160

llvm-svn: 153159

instructions have been scheduled. Handy for tracking down scheduler bugs, or
bugs exposed by scheduling.

llvm-svn: 153045

llvm-svn: 152711

New flags: -misched-topdown, -misched-bottomup. They can be used with
the default scheduler or with -misched=shuffle. Without either
topdown/bottomup flag -misched=shuffle now alternates scheduling
direction.

LiveIntervals update is unimplemented with bottom-up scheduling, so
only -misched-topdown currently works.

Capped the ScheduleDAG hierarchy with a concrete ScheduleDAGMI class.
ScheduleDAGMI is aware of the top and bottom of the unscheduled zone
within the current region. Scheduling policy can be plugged into
the ScheduleDAGMI driver by implementing MachineSchedStrategy.
ConvergingScheduler is now the default scheduling algorithm.
It exercises the new driver but still does no reordering.

llvm-svn: 152700

llvm-svn: 152699

And add comments, since this is obviously confusing.

llvm-svn: 152445

llvm-svn: 152393

llvm-svn: 152382

llvm-svn: 152374

llvm-svn: 152373

llvm-svn: 152360

llvm-svn: 152356

Allow targets to provide their own schedulers (subclass of
ScheduleDAGInstrs) to the misched pass. Select schedulers using
-misched=...

llvm-svn: 152278

implement their own MachineScheduler.

llvm-svn: 152261

ScheduleDAGInstrs knows nothing about how instructions will be moved or inserted.

llvm-svn: 152256

We had half the API with one convention, half with another. Now was a
good time to clean it up.

llvm-svn: 152255

ScheduleDAG is responsible for the DAG: SUnits and SDeps. It provides target hooks for latency computation.

ScheduleDAGInstrs extends ScheduleDAG and defines the current scheduling region in terms of MachineInstr iterators. It has access to the target's scheduling itinerary data. ScheduleDAGInstrs provides the logic for building the ScheduleDAG for the sequence of MachineInstrs in the current region. Target's can implement highly custom schedulers by extending this class.

ScheduleDAGPostRATDList provides the driver and diagnostics for current postRA scheduling. It maintains a current Sequence of scheduled machine instructions and logic for splicing them into the block. During scheduling, it uses the ScheduleHazardRecognizer provided by the target.

Specific changes:
- Removed driver code from ScheduleDAG. clearDAG is the only interface needed.

- Added enterRegion/exitRegion hooks to ScheduleDAGInstrs to delimit the scope of each scheduling region and associated DAG. They should be used to setup and cleanup any region-specific state in addition to the DAG itself. This is necessary because we reuse the same ScheduleDAG object for the entire function. The target may extend these hooks to do things at regions boundaries, like bundle terminators. The hooks are called even if we decide not to schedule the region. So all instructions in a block are "covered" by these calls.

- Added ScheduleDAGInstrs::begin()/end() public API.

- Moved Sequence into the driver layer, which is specific to the scheduling algorithm.

llvm-svn: 152208

llvm-svn: 152178

llvm-svn: 152172