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Fix a bug in RemoveDeadNodes where it would crash when its "optional" 

argument is not specified.

Implement ReplaceAllUsesWith.

llvm-svn: 22834
This commit is contained in:
Chris Lattner 2005-08-17 19:00:20 +00:00
parent 1c911aea08
commit ab0de9d7fc
1 changed files with 77 additions and 1 deletions
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78
llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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@ -152,7 +152,8 @@ void SelectionDAG::RemoveDeadNodes(SDNode *N) {
// to the root node, preventing it from being deleted.
SDNode *DummyNode = new SDNode(ISD::EntryToken, getRoot());
DeleteNodeIfDead(N, &AllNodeSet);
// If we have a hint to start from, use it.
if (N) DeleteNodeIfDead(N, &AllNodeSet);
Restart:
unsigned NumNodes = AllNodeSet.size();
@ -292,6 +293,51 @@ void SelectionDAG::RemoveNodeFromCSEMaps(SDNode *N) {
}
}
/// AddNonLeafNodeToCSEMaps - Add the specified node back to the CSE maps. It
/// has been taken out and modified in some way. If the specified node already
/// exists in the CSE maps, do not modify the maps, but return the existing node
/// instead. If it doesn't exist, add it and return null.
///
SDNode *SelectionDAG::AddNonLeafNodeToCSEMaps(SDNode *N) {
assert(N->getNumOperands() && "This is a leaf node!");
if (N->getOpcode() == ISD::LOAD) {
SDNode *&L = Loads[std::make_pair(N->getOperand(1),
std::make_pair(N->getOperand(0),
N->getValueType(0)))];
if (L) return L;
L = N;
} else if (N->getNumOperands() == 1) {
SDNode *&U = UnaryOps[std::make_pair(N->getOpcode(),
std::make_pair(N->getOperand(0),
N->getValueType(0)))];
if (U) return U;
U = N;
} else if (N->getNumOperands() == 2) {
SDNode *&B = BinaryOps[std::make_pair(N->getOpcode(),
std::make_pair(N->getOperand(0),
N->getOperand(1)))];
if (B) return B;
B = N;
} else if (N->getNumValues() == 1) {
std::vector<SDOperand> Ops(N->op_begin(), N->op_end());
SDNode *&ORN = OneResultNodes[std::make_pair(N->getOpcode(),
std::make_pair(N->getValueType(0), Ops))];
if (ORN) return ORN;
ORN = N;
} else {
// Remove the node from the ArbitraryNodes map.
std::vector<MVT::ValueType> RV(N->value_begin(), N->value_end());
std::vector<SDOperand> Ops(N->op_begin(), N->op_end());
SDNode *&AN = ArbitraryNodes[std::make_pair(N->getOpcode(),
std::make_pair(RV, Ops))];
if (AN) return AN;
AN = N;
}
return 0;
}
SelectionDAG::~SelectionDAG() {
for (unsigned i = 0, e = AllNodes.size(); i != e; ++i)
@ -1758,6 +1804,36 @@ void SelectionDAG::SelectNodeTo(SDNode *N, MVT::ValueType VT,
N->setOperands(Op1, Op2, Op3);
}
/// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
/// This can cause recursive merging of nodes in the DAG.
///
void SelectionDAG::ReplaceAllUsesWith(SDNode *From, SDNode *To) {
assert(From != To && "Cannot replace uses of with self");
while (!From->use_empty()) {
// Process users until they are all gone.
SDNode *U = *From->use_begin();
// This node is about to morph, remove its old self from the CSE maps.
RemoveNodeFromCSEMaps(U);
for (unsigned i = 0, e = U->getNumOperands(); i != e; ++i)
if (U->getOperand(i).Val == From) {
assert(From->getValueType(U->getOperand(i).ResNo) ==
To->getValueType(U->getOperand(i).ResNo));
From->removeUser(U);
U->Operands[i].Val = To;
To->addUser(U);
}
// Now that we have modified U, add it back to the CSE maps. If it already
// exists there, recursively merge the results together.
if (SDNode *Existing = AddNonLeafNodeToCSEMaps(U))
ReplaceAllUsesWith(U, Existing);
// U is now dead.
}
}
/// hasNUsesOfValue - Return true if there are exactly NUSES uses of the
/// indicated value. This method ignores uses of other values defined by this