Added isPredecessor.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31409 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index c2ee956..fe33ff5 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2563,6 +2563,29 @@
return false;
}
+static void findPredecessor(SDNode *N, const SDNode *P, bool &found,
+ std::set<SDNode *> &Visited) {
+ if (found || !Visited.insert(N).second)
+ return;
+
+ for (unsigned i = 0, e = N->getNumOperands(); !found && i != e; ++i) {
+ SDNode *Op = N->getOperand(i).Val;
+ if (Op == P) {
+ found = true;
+ return;
+ }
+ findPredecessor(Op, P, found, Visited);
+ }
+}
+
+// isPredecessor - Return true if this node is a predecessor of N.
+bool SDNode::isPredecessor(SDNode *N) const {
+ std::set<SDNode *> Visited;
+ bool found = false;
+ findPredecessor(N, this, found, Visited);
+ return found;
+}
+
uint64_t SDNode::getConstantOperandVal(unsigned Num) const {
assert(Num < NumOperands && "Invalid child # of SDNode!");
return cast<ConstantSDNode>(OperandList[Num])->getValue();