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Speed-up the SumOfUnscheduledPredsOfSuccs by introducing a new function 

called LimitedSumOfUnscheduledPredsOfSuccs. It terminates the computation
after a given treshold is reached. This new function is always faster, but
brings real wins only on bigger test-cases.

The old function SumOfUnscheduledPredsOfSuccs is left in-place for now and therefore a warning about an unused static function is produced.

llvm-svn: 48872
This commit is contained in:
Roman Levenstein 2008-03-27 09:14:57 +00:00
parent a5e13fab86
commit bc674501ba
1 changed files with 25 additions and 2 deletions
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27
llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
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@ -1724,6 +1724,29 @@ static unsigned SumOfUnscheduledPredsOfSuccs(const SUnit *SU) {
return Sum; return Sum;
} }
/// LimitedSumOfUnscheduledPredsOfSuccs - compute the sum of the unscheduled
/// predecessors of the successors of the SUnit SU. Stop when the provided
/// limit is exceeded.
static unsigned LimitedSumOfUnscheduledPredsOfSuccs(const SUnit *SU,
unsigned Limit) {
unsigned Sum = 0;
for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
SUnit *SuccSU = I->Dep;
for (SUnit::const_pred_iterator II = SuccSU->Preds.begin(),
EE = SuccSU->Preds.end(); II != EE; ++II) {
SUnit *PredSU = II->Dep;
if (!PredSU->isScheduled) {
++Sum;
if(Sum > Limit)
return Sum;
}
}
}
return Sum;
}
// Top down // Top down
bool td_ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const { bool td_ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const {
@ -1733,8 +1756,8 @@ bool td_ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const {
bool RIsTarget = right->Node && right->Node->isTargetOpcode(); bool RIsTarget = right->Node && right->Node->isTargetOpcode();
bool LIsFloater = LIsTarget && left->NumPreds == 0; bool LIsFloater = LIsTarget && left->NumPreds == 0;
bool RIsFloater = RIsTarget && right->NumPreds == 0; bool RIsFloater = RIsTarget && right->NumPreds == 0;
unsigned LBonus = (SumOfUnscheduledPredsOfSuccs(left) == 1) ? 2 : 0; unsigned LBonus = (LimitedSumOfUnscheduledPredsOfSuccs(left,1) == 1) ? 2 : 0;
unsigned RBonus = (SumOfUnscheduledPredsOfSuccs(right) == 1) ? 2 : 0; unsigned RBonus = (LimitedSumOfUnscheduledPredsOfSuccs(right,1) == 1) ? 2 : 0;
if (left->NumSuccs == 0 && right->NumSuccs != 0) if (left->NumSuccs == 0 && right->NumSuccs != 0)
return false; return false;