Added MachineSchedPolicy.
Allow subtargets to customize the generic scheduling strategy.
This is convenient for targets that don't need to add new heuristics
by specializing the strategy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190176 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp
index 9600cb6..b854a13 100644
--- a/lib/CodeGen/MachineScheduler.cpp
+++ b/lib/CodeGen/MachineScheduler.cpp
@@ -480,12 +480,13 @@
{
ScheduleDAGInstrs::enterRegion(bb, begin, end, regioninstrs);
- ShouldTrackPressure =
- EnableRegPressure && SchedImpl->shouldTrackPressure(regioninstrs);
-
// For convenience remember the end of the liveness region.
LiveRegionEnd =
(RegionEnd == bb->end()) ? RegionEnd : llvm::next(RegionEnd);
+
+ SchedImpl->initPolicy(begin, end, regioninstrs);
+
+ ShouldTrackPressure = SchedImpl->shouldTrackPressure();
}
// Setup the register pressure trackers for the top scheduled top and bottom
@@ -1594,12 +1595,7 @@
SchedBoundary Top;
SchedBoundary Bot;
- // Allow the driver to force top-down or bottom-up scheduling. If neither is
- // true, the scheduler runs in both directions and converges. For generic
- // targets, we default to bottom-up, because it's simpler and more
- // compile-time optimizations have been implemented in that direction.
- bool OnlyBottomUp;
- bool OnlyTopDown;
+ MachineSchedPolicy RegionPolicy;
public:
/// SUnit::NodeQueueId: 0 (none), 1 (top), 2 (bot), 3 (both)
enum {
@@ -1610,10 +1606,13 @@
ConvergingScheduler(const MachineSchedContext *C):
Context(C), DAG(0), SchedModel(0), TRI(0),
- Top(TopQID, "TopQ"), Bot(BotQID, "BotQ"),
- OnlyBottomUp(true), OnlyTopDown(false) {}
+ Top(TopQID, "TopQ"), Bot(BotQID, "BotQ") {}
- virtual bool shouldTrackPressure(unsigned NumRegionInstrs);
+ virtual void initPolicy(MachineBasicBlock::iterator Begin,
+ MachineBasicBlock::iterator End,
+ unsigned NumRegionInstrs);
+
+ bool shouldTrackPressure() const { return RegionPolicy.ShouldTrackPressure; }
virtual void initialize(ScheduleDAGMI *dag);
@@ -1681,14 +1680,46 @@
ExecutedResCounts.resize(SchedModel->getNumProcResourceKinds());
}
-/// Avoid setting up the register pressure tracker for small regions to save
-/// compile time. As a rough heuristic, only track pressure when the number
-/// of schedulable instructions exceeds half the integer register file.
-bool ConvergingScheduler::shouldTrackPressure(unsigned NumRegionInstrs) {
- unsigned NIntRegs = Context->RegClassInfo->getNumAllocatableRegs(
- Context->MF->getTarget().getTargetLowering()->getRegClassFor(MVT::i32));
+/// Initialize the per-region scheduling policy.
+void ConvergingScheduler::initPolicy(MachineBasicBlock::iterator Begin,
+ MachineBasicBlock::iterator End,
+ unsigned NumRegionInstrs) {
+ const TargetMachine &TM = Context->MF->getTarget();
- return NumRegionInstrs > (NIntRegs / 2);
+ // Avoid setting up the register pressure tracker for small regions to save
+ // compile time. As a rough heuristic, only track pressure when the number of
+ // schedulable instructions exceeds half the integer register file.
+ unsigned NIntRegs = Context->RegClassInfo->getNumAllocatableRegs(
+ TM.getTargetLowering()->getRegClassFor(MVT::i32));
+
+ RegionPolicy.ShouldTrackPressure = NumRegionInstrs > (NIntRegs / 2);
+
+ // For generic targets, we default to bottom-up, because it's simpler and more
+ // compile-time optimizations have been implemented in that direction.
+ RegionPolicy.OnlyBottomUp = true;
+
+ // Allow the subtarget to override default policy.
+ const TargetSubtargetInfo &ST = TM.getSubtarget<TargetSubtargetInfo>();
+ ST.overrideSchedPolicy(RegionPolicy, Begin, End, NumRegionInstrs);
+
+ // After subtarget overrides, apply command line options.
+ if (!EnableRegPressure)
+ RegionPolicy.ShouldTrackPressure = false;
+
+ // Check -misched-topdown/bottomup can force or unforce scheduling direction.
+ // e.g. -misched-bottomup=false allows scheduling in both directions.
+ assert((!ForceTopDown || !ForceBottomUp) &&
+ "-misched-topdown incompatible with -misched-bottomup");
+ if (ForceBottomUp.getNumOccurrences() > 0) {
+ RegionPolicy.OnlyBottomUp = ForceBottomUp;
+ if (RegionPolicy.OnlyBottomUp)
+ RegionPolicy.OnlyTopDown = false;
+ }
+ if (ForceTopDown.getNumOccurrences() > 0) {
+ RegionPolicy.OnlyTopDown = ForceTopDown;
+ if (RegionPolicy.OnlyTopDown)
+ RegionPolicy.OnlyBottomUp = false;
+ }
}
void ConvergingScheduler::initialize(ScheduleDAGMI *dag) {
@@ -1714,21 +1745,6 @@
Bot.HazardRec =
TM.getInstrInfo()->CreateTargetMIHazardRecognizer(Itin, DAG);
}
- assert((!ForceTopDown || !ForceBottomUp) &&
- "-misched-topdown incompatible with -misched-bottomup");
-
- // Check -misched-topdown/bottomup can force or unforce scheduling direction.
- // e.g. -misched-bottomup=false allows scheduling in both directions.
- if (ForceBottomUp.getNumOccurrences() > 0) {
- OnlyBottomUp = ForceBottomUp;
- if (OnlyBottomUp)
- OnlyTopDown = false;
- }
- if (ForceTopDown.getNumOccurrences() > 0) {
- OnlyTopDown = ForceTopDown;
- if (OnlyTopDown)
- OnlyBottomUp = false;
- }
}
void ConvergingScheduler::releaseTopNode(SUnit *SU) {
@@ -2694,7 +2710,7 @@
}
SUnit *SU;
do {
- if (OnlyTopDown) {
+ if (RegionPolicy.OnlyTopDown) {
SU = Top.pickOnlyChoice();
if (!SU) {
CandPolicy NoPolicy;
@@ -2706,7 +2722,7 @@
}
IsTopNode = true;
}
- else if (OnlyBottomUp) {
+ else if (RegionPolicy.OnlyBottomUp) {
SU = Bot.pickOnlyChoice();
if (!SU) {
CandPolicy NoPolicy;