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Reapply 155668: Fix the SD scheduler to avoid gluing the same node twice.

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This time, also fix the caller of AddGlue to properly handle
incomplete chains. AddGlue had failure modes, but shamefully hid them
from its caller. It's luck ran out.

Fixes rdar://11314175: BuildSchedUnits assert.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155749 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick
2012-04-28 01:03:23 +00:00
parent a9cc08f24f
commit 2674a4acdb
2 changed files with 104 additions and 26 deletions
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84
lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
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@@ -131,28 +131,16 @@ static void CheckForPhysRegDependency(SDNode *Def, SDNode *User, unsigned Op,
}
}
static void AddGlue(SDNode *N, SDValue Glue, bool AddGlue, SelectionDAG *DAG) {
SmallVector<EVT, 4> VTs;
SDNode *GlueDestNode = Glue.getNode();
// Don't add glue from a node to itself.
if (GlueDestNode == N) return;
// Don't add glue to something that already has it, either as a use or value.
if (N->getValueType(N->getNumValues() - 1) == MVT::Glue) return;
for (unsigned I = 0, E = N->getNumValues(); I != E; ++I)
VTs.push_back(N->getValueType(I));
if (AddGlue)
VTs.push_back(MVT::Glue);
// Helper for AddGlue to clone node operands.
static void CloneNodeWithValues(SDNode *N, SelectionDAG *DAG,
SmallVectorImpl<EVT> &VTs,
SDValue ExtraOper = SDValue()) {
SmallVector<SDValue, 4> Ops;
for (unsigned I = 0, E = N->getNumOperands(); I != E; ++I)
Ops.push_back(N->getOperand(I));
if (GlueDestNode)
Ops.push_back(Glue);
if (ExtraOper.getNode())
Ops.push_back(ExtraOper);
SDVTList VTList = DAG->getVTList(&VTs[0], VTs.size());
MachineSDNode::mmo_iterator Begin = 0, End = 0;
@@ -171,6 +159,46 @@ static void AddGlue(SDNode *N, SDValue Glue, bool AddGlue, SelectionDAG *DAG) {
MN->setMemRefs(Begin, End);
}
static bool AddGlue(SDNode *N, SDValue Glue, bool AddGlue, SelectionDAG *DAG) {
SmallVector<EVT, 4> VTs;
SDNode *GlueDestNode = Glue.getNode();
// Don't add glue from a node to itself.
if (GlueDestNode == N) return false;
// Don't add a glue operand to something that already uses glue.
if (GlueDestNode &&
N->getOperand(N->getNumOperands()-1).getValueType() == MVT::Glue) {
return false;
}
// Don't add glue to something that already has a glue value.
if (N->getValueType(N->getNumValues() - 1) == MVT::Glue) return false;
for (unsigned I = 0, E = N->getNumValues(); I != E; ++I)
VTs.push_back(N->getValueType(I));
if (AddGlue)
VTs.push_back(MVT::Glue);
CloneNodeWithValues(N, DAG, VTs, Glue);
return true;
}
// Cleanup after unsuccessful AddGlue. Use the standard method of morphing the
// node even though simply shrinking the value list is sufficient.
static void RemoveUnusedGlue(SDNode *N, SelectionDAG *DAG) {
assert((N->getValueType(N->getNumValues() - 1) == MVT::Glue &&
!N->hasAnyUseOfValue(N->getNumValues() - 1)) &&
"expected an unused glue value");
SmallVector<EVT, 4> VTs;
for (unsigned I = 0, E = N->getNumValues()-1; I != E; ++I)
VTs.push_back(N->getValueType(I));
CloneNodeWithValues(N, DAG, VTs);
}
/// ClusterNeighboringLoads - Force nearby loads together by "gluing" them.
/// This function finds loads of the same base and different offsets. If the
/// offsets are not far apart (target specific), it add MVT::Glue inputs and
@@ -238,19 +266,23 @@ void ScheduleDAGSDNodes::ClusterNeighboringLoads(SDNode *Node) {
// Cluster loads by adding MVT::Glue outputs and inputs. This also
// ensure they are scheduled in order of increasing addresses.
SDNode *Lead = Loads[0];
AddGlue(Lead, SDValue(0, 0), true, DAG);
SDValue InGlue = SDValue(Lead, Lead->getNumValues() - 1);
SDValue InGlue = SDValue(0, 0);
if (AddGlue(Lead, InGlue, true, DAG))
InGlue = SDValue(Lead, Lead->getNumValues() - 1);
for (unsigned I = 1, E = Loads.size(); I != E; ++I) {
bool OutGlue = I < E - 1;
SDNode *Load = Loads[I];
AddGlue(Load, InGlue, OutGlue, DAG);
// If AddGlue fails, we could leave an unsused glue value. This should not
// cause any
if (AddGlue(Load, InGlue, OutGlue, DAG)) {
if (OutGlue)
InGlue = SDValue(Load, Load->getNumValues() - 1);
if (OutGlue)
InGlue = SDValue(Load, Load->getNumValues() - 1);
++LoadsClustered;
++LoadsClustered;
}
else if (!OutGlue && InGlue.getNode())
RemoveUnusedGlue(InGlue.getNode(), DAG);
}
}