Introducing a new method of tracking register pressure. We can't
precisely track pressure on a selection DAG, but we can at least keep
it balanced. This design accounts for various interesting aspects of
selection DAGS: register and subregister copies, glued nodes, dead
nodes, unused registers, etc.
Added SUnit::NumRegDefsLeft and ScheduleDAGSDNodes::RegDefIter.
Note: I disabled PrescheduleNodesWithMultipleUses when register
pressure is enabled, based on no evidence other than I don't think it
makes sense to have both enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124853 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ScheduleDAG.cpp b/lib/CodeGen/ScheduleDAG.cpp
index 83f2dd0..3388889 100644
--- a/lib/CodeGen/ScheduleDAG.cpp
+++ b/lib/CodeGen/ScheduleDAG.cpp
@@ -75,12 +75,12 @@
/// addPred - This adds the specified edge as a pred of the current node if
/// not already. It also adds the current node as a successor of the
/// specified node.
-void SUnit::addPred(const SDep &D) {
+bool SUnit::addPred(const SDep &D) {
// If this node already has this depenence, don't add a redundant one.
for (SmallVector<SDep, 4>::const_iterator I = Preds.begin(), E = Preds.end();
I != E; ++I)
if (*I == D)
- return;
+ return false;
// Now add a corresponding succ to N.
SDep P = D;
P.setSUnit(this);
@@ -106,6 +106,7 @@
this->setDepthDirty();
N->setHeightDirty();
}
+ return true;
}
/// removePred - This removes the specified edge as a pred of the current
@@ -285,6 +286,7 @@
dbgs() << " # preds left : " << NumPredsLeft << "\n";
dbgs() << " # succs left : " << NumSuccsLeft << "\n";
+ dbgs() << " # rdefs left : " << NumRegDefsLeft << "\n";
dbgs() << " Latency : " << Latency << "\n";
dbgs() << " Depth : " << Depth << "\n";
dbgs() << " Height : " << Height << "\n";