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[AMDGPU/MemOpsCluster] Code clean-up around mem ops clustering logic 

Summary:
Clean-up code around mem ops clustering logic. This patch cleans up code within
the function clusterNeighboringMemOps(). It is WIP, and this patch is a first cut.

Reviewers: foad, rampitec, arsenm, vpykhtin, javedabsar

Reviewed By: foad

Subscribers: MatzeB, kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, hiraditya, javed.absar, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80119
This commit is contained in:
hsmahesha 2020-05-26 15:47:03 +05:30
parent 6f802ec433
commit 09f7dcb64e
1 changed files with 39 additions and 25 deletions
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64
llvm/lib/CodeGen/MachineScheduler.cpp
View File

@ -1580,34 +1580,48 @@ void BaseMemOpClusterMutation::clusterNeighboringMemOps(
return;
llvm::sort(MemOpRecords);
// At this point, `MemOpRecords` array must hold atleast two mem ops. Try to
// cluster mem ops collected within `MemOpRecords` array.
unsigned ClusterLength = 1;
for (unsigned Idx = 0, End = MemOpRecords.size(); Idx < (End - 1); ++Idx) {
SUnit *SUa = MemOpRecords[Idx].SU;
SUnit *SUb = MemOpRecords[Idx+1].SU;
if (TII->shouldClusterMemOps(MemOpRecords[Idx].BaseOps,
MemOpRecords[Idx + 1].BaseOps,
ClusterLength + 1)) {
if (SUa->NodeNum > SUb->NodeNum)
std::swap(SUa, SUb);
if (DAG->addEdge(SUb, SDep(SUa, SDep::Cluster))) {
LLVM_DEBUG(dbgs() << "Cluster ld/st SU(" << SUa->NodeNum << ") - SU("
<< SUb->NodeNum << ")\n");
// Copy successor edges from SUa to SUb. Interleaving computation
// dependent on SUa can prevent load combining due to register reuse.
// Predecessor edges do not need to be copied from SUb to SUa since
// nearby loads should have effectively the same inputs.
for (const SDep &Succ : SUa->Succs) {
if (Succ.getSUnit() == SUb)
continue;
LLVM_DEBUG(dbgs()
<< " Copy Succ SU(" << Succ.getSUnit()->NodeNum << ")\n");
DAG->addEdge(Succ.getSUnit(), SDep(SUb, SDep::Artificial));
}
++ClusterLength;
} else
ClusterLength = 1;
} else
// Decision to cluster mem ops is taken based on target dependent logic
auto MemOpa = MemOpRecords[Idx];
auto MemOpb = MemOpRecords[Idx + 1];
++ClusterLength;
if (!TII->shouldClusterMemOps(MemOpa.BaseOps, MemOpb.BaseOps,
ClusterLength)) {
// Current mem ops pair could not be clustered, reset cluster length, and
// go to next pair
ClusterLength = 1;
continue;
}
SUnit *SUa = MemOpa.SU;
SUnit *SUb = MemOpb.SU;
if (SUa->NodeNum > SUb->NodeNum)
std::swap(SUa, SUb);
// FIXME: Is this check really required?
if (!DAG->addEdge(SUb, SDep(SUa, SDep::Cluster))) {
ClusterLength = 1;
continue;
}
LLVM_DEBUG(dbgs() << "Cluster ld/st SU(" << SUa->NodeNum << ") - SU("
<< SUb->NodeNum << ")\n");
// Copy successor edges from SUa to SUb. Interleaving computation
// dependent on SUa can prevent load combining due to register reuse.
// Predecessor edges do not need to be copied from SUb to SUa since
// nearby loads should have effectively the same inputs.
for (const SDep &Succ : SUa->Succs) {
if (Succ.getSUnit() == SUb)
continue;
LLVM_DEBUG(dbgs() << " Copy Succ SU(" << Succ.getSUnit()->NodeNum
<< ")\n");
DAG->addEdge(Succ.getSUnit(), SDep(SUb, SDep::Artificial));
}
}
}