It's possible that a flag is added to the SDNode that points back to the
original SDNode. This is badness. Also, this function allows one SDNode to point
multiple flags to another SDNode. Badness as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106793 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index 07277b3..c54f360 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -110,18 +110,25 @@
static void AddFlags(SDNode *N, SDValue Flag, bool AddFlag,
SelectionDAG *DAG) {
SmallVector<EVT, 4> VTs;
+ SDNode *FlagDestNode = Flag.getNode();
- for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
- VTs.push_back(N->getValueType(i));
+ // Don't add a flag from a node to itself.
+ if (FlagDestNode == N) return;
+
+ // Don't add a flag to something which already has a flag.
+ if (N->getValueType(N->getNumValues() - 1) == MVT::Flag) return;
+
+ for (unsigned I = 0, E = N->getNumValues(); I != E; ++I)
+ VTs.push_back(N->getValueType(I));
if (AddFlag)
VTs.push_back(MVT::Flag);
SmallVector<SDValue, 4> Ops;
- for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
- Ops.push_back(N->getOperand(i));
+ for (unsigned I = 0, E = N->getNumOperands(); I != E; ++I)
+ Ops.push_back(N->getOperand(I));
- if (Flag.getNode())
+ if (FlagDestNode)
Ops.push_back(Flag);
SDVTList VTList = DAG->getVTList(&VTs[0], VTs.size());
@@ -213,16 +220,17 @@
// Cluster loads by adding MVT::Flag outputs and inputs. This also
// ensure they are scheduled in order of increasing addresses.
SDNode *Lead = Loads[0];
- AddFlags(Lead, SDValue(0,0), true, DAG);
+ AddFlags(Lead, SDValue(0, 0), true, DAG);
- SDValue InFlag = SDValue(Lead, Lead->getNumValues()-1);
- for (unsigned i = 1, e = Loads.size(); i != e; ++i) {
- bool OutFlag = i < e-1;
- SDNode *Load = Loads[i];
+ SDValue InFlag = SDValue(Lead, Lead->getNumValues() - 1);
+ for (unsigned I = 1, E = Loads.size(); I != E; ++I) {
+ bool OutFlag = I < E - 1;
+ SDNode *Load = Loads[I];
+
AddFlags(Load, InFlag, OutFlag, DAG);
if (OutFlag)
- InFlag = SDValue(Load, Load->getNumValues()-1);
+ InFlag = SDValue(Load, Load->getNumValues() - 1);
++LoadsClustered;
}