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mi-sched: update PressureDiffs on-the-fly for liveness.

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This removes all expensive pressure tracking logic from the scheduling
critical path of node comparison.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189643 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick
2013-08-30 04:36:57 +00:00
parent 1362dcb589
commit 663bd99227
6 changed files with 97 additions and 31 deletions
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40
lib/CodeGen/RegisterPressure.cpp
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@@ -399,10 +399,9 @@ static void collectPDiff(PressureDiff &PDiff, RegisterOperands &RegOpers,
const MachineRegisterInfo *MRI) {
assert(!PDiff.begin()->isValid() && "stale PDiff");
for (unsigned i = 0, e = RegOpers.Defs.size(); i != e; ++i) {
if (!containsReg(RegOpers.Uses, RegOpers.Defs[i]))
PDiff.addPressureChange(RegOpers.Defs[i], true, MRI);
}
for (unsigned i = 0, e = RegOpers.Defs.size(); i != e; ++i)
PDiff.addPressureChange(RegOpers.Defs[i], true, MRI);
for (unsigned i = 0, e = RegOpers.Uses.size(); i != e; ++i)
PDiff.addPressureChange(RegOpers.Uses[i], false, MRI);
}
@@ -437,9 +436,13 @@ void RegPressureTracker::discoverLiveOut(unsigned Reg) {
increaseSetPressure(P.MaxSetPressure, MRI->getPressureSets(Reg));
}
/// Recede across the previous instruction.
/// Record the pressure difference if it is provided.
bool RegPressureTracker::recede(PressureDiff *PDiff) {
/// Recede across the previous instruction. If LiveUses is provided, record any
/// RegUnits that are made live by the current instruction's uses. This includes
/// registers that are both defined and used by the instruction. If a pressure
/// difference pointer is provided record the changes is pressure caused by this
/// instruction independent of liveness.
bool RegPressureTracker::recede(SmallVectorImpl<unsigned> *LiveUses,
PressureDiff *PDiff) {
// Check for the top of the analyzable region.
if (CurrPos == MBB->begin()) {
closeRegion();
@@ -496,11 +499,16 @@ bool RegPressureTracker::recede(PressureDiff *PDiff) {
// Adjust liveouts if LiveIntervals are available.
if (RequireIntervals) {
const LiveInterval *LI = getInterval(Reg);
if (LI && !LI->isKilledAtInstr(SlotIdx))
discoverLiveOut(Reg);
// Check if this LR is killed and not redefined here.
if (LI && !LI->isKilledAtInstr(SlotIdx)
&& !LI->isDefinedByInstr(SlotIdx)) {
discoverLiveOut(Reg);
}
}
increaseRegPressure(Reg);
LiveRegs.insert(Reg);
if (LiveUses && !containsReg(*LiveUses, Reg))
LiveUses->push_back(Reg);
}
}
if (TrackUntiedDefs) {
@@ -773,22 +781,10 @@ getMaxUpwardPressureDelta(const MachineInstr *MI, PressureDiff *PDiff,
/// @param MaxPressureLimit Is the max pressure within the region, not
/// necessarily at the current position.
void RegPressureTracker::
getUpwardPressureDelta(const MachineInstr *MI, /*const*/ PressureDiff &PDiff1,
getUpwardPressureDelta(const MachineInstr *MI, /*const*/ PressureDiff &PDiff,
RegPressureDelta &Delta,
ArrayRef<PressureChange> CriticalPSets,
ArrayRef<unsigned> MaxPressureLimit) const {
RegisterOperands RegOpers(TRI, MRI, /*IgnoreDead=*/true);
collectOperands(MI, RegOpers);
// Decrease the pressure change for live uses.
PressureDiff PDiff = PDiff1;
for (unsigned i = 0, e = RegOpers.Uses.size(); i != e; ++i) {
if (LiveRegs.contains(RegOpers.Uses[i]))
PDiff.addPressureChange(RegOpers.Uses[i], true, MRI);
}
// Now directly query pressure from PDiff. Everything above this can be
// cached and updated independent of the query.
unsigned CritIdx = 0, CritEnd = CriticalPSets.size();
for (PressureDiff::const_iterator
PDiffI = PDiff.begin(), PDiffE = PDiff.end();