[CodeGen] Move MacroFusion to the target

This patch moves the class for scheduling adjacent instructions,
MacroFusion, to the target.

In AArch64, it also expands the fusion to all instructions pairs in a
scheduling block, beyond just among the predecessors of the branch at the
end.

Differential revision: https://reviews.llvm.org/D28489

llvm-svn: 293737

1 files changed, 0 insertions, 74 deletions

diff --git a/llvm/lib/CodeGen/MachineScheduler.cpp b/llvm/lib/CodeGen/MachineScheduler.cpp
index ad3603e..168b883 100644
--- a/llvm/lib/CodeGen/MachineScheduler.cpp
+++ b/llvm/lib/CodeGen/MachineScheduler.cpp
@@ -80,10 +80,6 @@ static cl::opt<bool> EnableMemOpCluster("misched-cluster", cl::Hidden,
                                         cl::desc("Enable memop clustering."),
                                         cl::init(true));
 
-// Experimental heuristics
-static cl::opt<bool> EnableMacroFusion("misched-fusion", cl::Hidden,
-  cl::desc("Enable scheduling for macro fusion."), cl::init(true));
-
 static cl::opt<bool> VerifyScheduling("verify-misched", cl::Hidden,
   cl::desc("Verify machine instrs before and after machine scheduling"));
 
@@ -1544,76 +1540,6 @@ void BaseMemOpClusterMutation::apply(ScheduleDAGInstrs *DAGInstrs) {
 }
 
 //===----------------------------------------------------------------------===//
-// MacroFusion - DAG post-processing to encourage fusion of macro ops.
-//===----------------------------------------------------------------------===//
-
-namespace {
-/// \brief Post-process the DAG to create cluster edges between instructions
-/// that may be fused by the processor into a single operation.
-class MacroFusion : public ScheduleDAGMutation {
-  const TargetInstrInfo &TII;
-public:
-  MacroFusion(const TargetInstrInfo &TII)
-    : TII(TII) {}
-
-  void apply(ScheduleDAGInstrs *DAGInstrs) override;
-};
-} // anonymous
-
-namespace llvm {
-
-std::unique_ptr<ScheduleDAGMutation>
-createMacroFusionDAGMutation(const TargetInstrInfo *TII) {
-  return EnableMacroFusion ? make_unique<MacroFusion>(*TII) : nullptr;
-}
-
-} // namespace llvm
-
-/// \brief Callback from DAG postProcessing to create cluster edges to encourage
-/// fused operations.
-void MacroFusion::apply(ScheduleDAGInstrs *DAGInstrs) {
-  ScheduleDAGMI *DAG = static_cast<ScheduleDAGMI*>(DAGInstrs);
-
-  // For now, assume targets can only fuse with the branch.
-  SUnit &ExitSU = DAG->ExitSU;
-  MachineInstr *Branch = ExitSU.getInstr();
-  if (!Branch)
-    return;
-
-  for (SDep &PredDep : ExitSU.Preds) {
-    if (PredDep.isWeak())
-      continue;
-    SUnit &SU = *PredDep.getSUnit();
-    MachineInstr &Pred = *SU.getInstr();
-    if (!TII.shouldScheduleAdjacent(Pred, *Branch))
-      continue;
-
-    // Create a single weak edge from SU to ExitSU. The only effect is to cause
-    // bottom-up scheduling to heavily prioritize the clustered SU.  There is no
-    // need to copy predecessor edges from ExitSU to SU, since top-down
-    // scheduling cannot prioritize ExitSU anyway. To defer top-down scheduling
-    // of SU, we could create an artificial edge from the deepest root, but it
-    // hasn't been needed yet.
-    bool Success = DAG->addEdge(&ExitSU, SDep(&SU, SDep::Cluster));
-    (void)Success;
-    assert(Success && "No DAG nodes should be reachable from ExitSU");
-
-    // Adjust latency of data deps between the nodes.
-    for (SDep &PredDep : ExitSU.Preds) {
-      if (PredDep.getSUnit() == &SU)
-        PredDep.setLatency(0);
-    }
-    for (SDep &SuccDep : SU.Succs) {
-      if (SuccDep.getSUnit() == &ExitSU)
-        SuccDep.setLatency(0);
-    }
-
-    DEBUG(dbgs() << "Macro Fuse SU(" << SU.NodeNum << ")\n");
-    break;
-  }
-}
-
-//===----------------------------------------------------------------------===//
 // CopyConstrain - DAG post-processing to encourage copy elimination.
 //===----------------------------------------------------------------------===//