@@ -2461,43 +2461,47 @@ bool SwingSchedulerDAG::schedulePipeline(SMSchedule &Schedule) {
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// upon the scheduled time for any predecessors/successors.
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int EarlyStart = INT_MIN;
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int LateStart = INT_MAX;
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- Schedule.computeStart (SU, &EarlyStart, &LateStart, II, this );
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+ // These values are set when the size of the schedule window is limited
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+ // due to chain dependences.
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+ int SchedEnd = INT_MAX;
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+ int SchedStart = INT_MIN;
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+ Schedule.computeStart (SU, &EarlyStart, &LateStart, &SchedEnd, &SchedStart,
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+ II, this );
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LLVM_DEBUG ({
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dbgs () << " \n " ;
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dbgs () << " Inst (" << SU->NodeNum << " ) " ;
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SU->getInstr ()->dump ();
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dbgs () << " \n " ;
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});
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- LLVM_DEBUG (
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- dbgs () << format (" \t es: %8x ls: %8x\n " , EarlyStart, LateStart));
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+ LLVM_DEBUG ({
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+ dbgs () << format (" \t es: %8x ls: %8x me: %8x ms: %8x\n " , EarlyStart,
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+ LateStart, SchedEnd, SchedStart);
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+ });
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- if (EarlyStart > LateStart)
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+ if (EarlyStart > LateStart || SchedEnd < EarlyStart ||
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+ SchedStart > LateStart)
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scheduleFound = false ;
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- else if (EarlyStart != INT_MIN && LateStart == INT_MAX)
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- scheduleFound =
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- Schedule.insert (SU, EarlyStart, EarlyStart + (int )II - 1 , II);
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- else if (EarlyStart == INT_MIN && LateStart != INT_MAX)
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- scheduleFound =
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- Schedule.insert (SU, LateStart, LateStart - (int )II + 1 , II);
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- else if (EarlyStart != INT_MIN && LateStart != INT_MAX) {
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- LateStart = std::min (LateStart, EarlyStart + (int )II - 1 );
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- // When scheduling a Phi it is better to start at the late cycle and
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- // go backwards. The default order may insert the Phi too far away
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- // from its first dependence.
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- // Also, do backward search when all scheduled predecessors are
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- // loop-carried output/order dependencies. Empirically, there are also
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- // cases where scheduling becomes possible with backward search.
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- if (SU->getInstr ()->isPHI () ||
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- Schedule.onlyHasLoopCarriedOutputOrOrderPreds (SU, this ))
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- scheduleFound = Schedule.insert (SU, LateStart, EarlyStart, II);
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+ else if (EarlyStart != INT_MIN && LateStart == INT_MAX) {
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+ SchedEnd = std::min (SchedEnd, EarlyStart + (int )II - 1 );
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+ scheduleFound = Schedule.insert (SU, EarlyStart, SchedEnd, II);
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+ } else if (EarlyStart == INT_MIN && LateStart != INT_MAX) {
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+ SchedStart = std::max (SchedStart, LateStart - (int )II + 1 );
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+ scheduleFound = Schedule.insert (SU, LateStart, SchedStart, II);
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+ } else if (EarlyStart != INT_MIN && LateStart != INT_MAX) {
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+ SchedEnd =
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+ std::min (SchedEnd, std::min (LateStart, EarlyStart + (int )II - 1 ));
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+ // When scheduling a Phi it is better to start at the late cycle and go
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+ // backwards. The default order may insert the Phi too far away from
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+ // its first dependence.
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+ if (SU->getInstr ()->isPHI ())
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+ scheduleFound = Schedule.insert (SU, SchedEnd, EarlyStart, II);
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else
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- scheduleFound = Schedule.insert (SU, EarlyStart, LateStart , II);
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+ scheduleFound = Schedule.insert (SU, EarlyStart, SchedEnd , II);
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} else {
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int FirstCycle = Schedule.getFirstCycle ();
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scheduleFound = Schedule.insert (SU, FirstCycle + getASAP (SU),
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FirstCycle + getASAP (SU) + II - 1 , II);
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}
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-
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// Even if we find a schedule, make sure the schedule doesn't exceed the
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// allowable number of stages. We keep trying if this happens.
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if (scheduleFound)
@@ -2905,7 +2909,8 @@ static SUnit *multipleIterations(SUnit *SU, SwingSchedulerDAG *DAG) {
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// / Compute the scheduling start slot for the instruction. The start slot
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// / depends on any predecessor or successor nodes scheduled already.
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void SMSchedule::computeStart (SUnit *SU, int *MaxEarlyStart, int *MinLateStart,
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- int II, SwingSchedulerDAG *DAG) {
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+ int *MinEnd, int *MaxStart, int II,
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+ SwingSchedulerDAG *DAG) {
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// Iterate over each instruction that has been scheduled already. The start
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// slot computation depends on whether the previously scheduled instruction
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// is a predecessor or successor of the specified instruction.
@@ -2924,7 +2929,7 @@ void SMSchedule::computeStart(SUnit *SU, int *MaxEarlyStart, int *MinLateStart,
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*MaxEarlyStart = std::max (*MaxEarlyStart, EarlyStart);
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if (DAG->isLoopCarriedDep (SU, Dep, false )) {
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int End = earliestCycleInChain (Dep) + (II - 1 );
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- *MinLateStart = std::min (*MinLateStart , End);
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+ *MinEnd = std::min (*MinEnd , End);
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}
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} else {
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int LateStart = cycle - Dep.getLatency () +
@@ -2948,7 +2953,7 @@ void SMSchedule::computeStart(SUnit *SU, int *MaxEarlyStart, int *MinLateStart,
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*MinLateStart = std::min (*MinLateStart, LateStart);
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if (DAG->isLoopCarriedDep (SU, Dep)) {
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int Start = latestCycleInChain (Dep) + 1 - II;
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- *MaxEarlyStart = std::max (*MaxEarlyStart , Start);
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+ *MaxStart = std::max (*MaxStart , Start);
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}
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} else {
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int EarlyStart = cycle + Dep.getLatency () -
@@ -3141,19 +3146,6 @@ bool SMSchedule::isLoopCarriedDefOfUse(const SwingSchedulerDAG *SSD,
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return false ;
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}
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- // / Return true if all scheduled predecessors are loop-carried output/order
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- // / dependencies.
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- bool SMSchedule::onlyHasLoopCarriedOutputOrOrderPreds (
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- SUnit *SU, SwingSchedulerDAG *DAG) const {
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- for (const SDep &Pred : SU->Preds )
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- if (InstrToCycle.count (Pred.getSUnit ()) && !DAG->isBackedge (SU, Pred))
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- return false ;
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- for (const SDep &Succ : SU->Succs )
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- if (InstrToCycle.count (Succ.getSUnit ()) && DAG->isBackedge (SU, Succ))
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- return false ;
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- return true ;
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- }
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-
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// / Determine transitive dependences of unpipelineable instructions
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SmallSet<SUnit *, 8 > SMSchedule::computeUnpipelineableNodes (
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SwingSchedulerDAG *SSD, TargetInstrInfo::PipelinerLoopInfo *PLI) {
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