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Remove compareRPDelta.

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A complex, expensive heuristic with little value in the current design.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184132 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick
2013-06-17 21:45:11 +00:00
parent e0f6046241
commit f8e6d31341
1 changed files with 0 additions and 37 deletions
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37
lib/CodeGen/MachineScheduler.cpp
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@@ -2171,37 +2171,6 @@ void ConvergingScheduler::tryCandidate(SchedCandidate &Cand,
}
}
/// pickNodeFromQueue helper that returns true if the LHS reg pressure effect is
/// more desirable than RHS from scheduling standpoint.
static bool compareRPDelta(const RegPressureDelta &LHS,
const RegPressureDelta &RHS) {
// Compare each component of pressure in decreasing order of importance
// without checking if any are valid. Invalid PressureElements are assumed to
// have UnitIncrease==0, so are neutral.
// Avoid increasing the max critical pressure in the scheduled region.
if (LHS.Excess.UnitIncrease != RHS.Excess.UnitIncrease) {
DEBUG(dbgs() << " RP excess top - bot: "
<< (LHS.Excess.UnitIncrease - RHS.Excess.UnitIncrease) << '\n');
return LHS.Excess.UnitIncrease < RHS.Excess.UnitIncrease;
}
// Avoid increasing the max critical pressure in the scheduled region.
if (LHS.CriticalMax.UnitIncrease != RHS.CriticalMax.UnitIncrease) {
DEBUG(dbgs() << " RP critical top - bot: "
<< (LHS.CriticalMax.UnitIncrease - RHS.CriticalMax.UnitIncrease)
<< '\n');
return LHS.CriticalMax.UnitIncrease < RHS.CriticalMax.UnitIncrease;
}
// Avoid increasing the max pressure of the entire region.
if (LHS.CurrentMax.UnitIncrease != RHS.CurrentMax.UnitIncrease) {
DEBUG(dbgs() << " RP current top - bot: "
<< (LHS.CurrentMax.UnitIncrease - RHS.CurrentMax.UnitIncrease)
<< '\n');
return LHS.CurrentMax.UnitIncrease < RHS.CurrentMax.UnitIncrease;
}
return false;
}
#ifndef NDEBUG
const char *ConvergingScheduler::getReasonStr(
ConvergingScheduler::CandReason Reason) {
@@ -2357,12 +2326,6 @@ SUnit *ConvergingScheduler::pickNodeBidirectional(bool &IsTopNode) {
pickNodeFromQueue(Top, DAG->getTopRPTracker(), TopCand);
assert(TopCand.Reason != NoCand && "failed to find the first candidate");
// Check for a salient pressure difference and pick the best from either side.
if (compareRPDelta(TopCand.RPDelta, BotCand.RPDelta)) {
IsTopNode = true;
tracePick(TopCand, IsTopNode);
return TopCand.SU;
}
// Choose the queue with the most important (lowest enum) reason.
if (TopCand.Reason < BotCand.Reason) {
IsTopNode = true;