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Eliminate the loop that searches through each of the operands

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of each use in the SelectionDAG ReplaceAllUses* functions. Thanks
to Chris for spotting this opportunity.

Also, factor out code from all 5 of the ReplaceAllUses* functions
into AddNonLeafNodeToCSEMaps, which is now renamed
AddModifiedNodeToCSEMaps to more accurately reflect its purpose.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62964 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-01-25 16:29:12 +00:00
parent 74692c0d65
commit 399461095b
2 changed files with 177 additions and 194 deletions
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2
include/llvm/CodeGen/SelectionDAG.h
View File

@ -800,7 +800,7 @@ public:
private:
bool RemoveNodeFromCSEMaps(SDNode *N);
SDNode *AddNonLeafNodeToCSEMaps(SDNode *N);
void AddModifiedNodeToCSEMaps(SDNode *N, DAGUpdateListener *UpdateListener);
SDNode *FindModifiedNodeSlot(SDNode *N, SDValue Op, void *&InsertPos);
SDNode *FindModifiedNodeSlot(SDNode *N, SDValue Op1, SDValue Op2,
void *&InsertPos);

369
lib/CodeGen/SelectionDAG/SelectionDAG.cpp
View File

@ -651,20 +651,36 @@ bool SelectionDAG::RemoveNodeFromCSEMaps(SDNode *N) {
return Erased;
}
/// 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.
/// AddModifiedNodeToCSEMaps - The specified node has been removed from the CSE
/// maps and modified in place. Add it back to the CSE maps, unless an identical
/// node already exists, in which case transfer all its users to the existing
/// node. This transfer can potentially trigger recursive merging.
///
SDNode *SelectionDAG::AddNonLeafNodeToCSEMaps(SDNode *N) {
assert(N->getNumOperands() && "This is a leaf node!");
void
SelectionDAG::AddModifiedNodeToCSEMaps(SDNode *N,
DAGUpdateListener *UpdateListener) {
// For node types that aren't CSE'd, just act as if no identical node
// already exists.
if (!doNotCSE(N)) {
SDNode *Existing = CSEMap.GetOrInsertNode(N);
if (Existing != N) {
// If there was already an existing matching node, use ReplaceAllUsesWith
// to replace the dead one with the existing one. This can cause
// recursive merging of other unrelated nodes down the line.
ReplaceAllUsesWith(N, Existing, UpdateListener);
if (doNotCSE(N))
return 0;
// N is now dead. Inform the listener if it exists and delete it.
if (UpdateListener)
UpdateListener->NodeDeleted(N, Existing);
DeleteNodeNotInCSEMaps(N);
return;
}
}
SDNode *New = CSEMap.GetOrInsertNode(N);
if (New != N) return New; // Node already existed.
return 0;
// If the node doesn't already exist, we updated it. Inform a listener if
// it exists.
if (UpdateListener)
UpdateListener->NodeUpdated(N);
}
/// FindModifiedNodeSlot - Find a slot for the specified node if its operands
@ -3900,8 +3916,7 @@ SDValue SelectionDAG::UpdateNodeOperands(SDValue InN, SDValue Op) {
// Now we update the operands.
N->OperandList[0].getVal()->removeUser(0, N);
N->OperandList[0] = Op;
N->OperandList[0].setUser(N);
N->OperandList[0].getSDValue() = Op;
Op.getNode()->addUser(0, N);
// If this gets put into a CSE map, add it.
@ -3931,14 +3946,12 @@ UpdateNodeOperands(SDValue InN, SDValue Op1, SDValue Op2) {
// Now we update the operands.
if (N->OperandList[0] != Op1) {
N->OperandList[0].getVal()->removeUser(0, N);
N->OperandList[0] = Op1;
N->OperandList[0].setUser(N);
N->OperandList[0].getSDValue() = Op1;
Op1.getNode()->addUser(0, N);
}
if (N->OperandList[1] != Op2) {
N->OperandList[1].getVal()->removeUser(1, N);
N->OperandList[1] = Op2;
N->OperandList[1].setUser(N);
N->OperandList[1].getSDValue() = Op2;
Op2.getNode()->addUser(1, N);
}
@ -3999,8 +4012,7 @@ UpdateNodeOperands(SDValue InN, const SDValue *Ops, unsigned NumOps) {
for (unsigned i = 0; i != NumOps; ++i) {
if (N->OperandList[i] != Ops[i]) {
N->OperandList[i].getVal()->removeUser(i, N);
N->OperandList[i] = Ops[i];
N->OperandList[i].setUser(N);
N->OperandList[i].getSDValue() = Ops[i];
Ops[i].getNode()->addUser(i, N);
}
}
@ -4272,7 +4284,7 @@ SDNode *SelectionDAG::MorphNodeTo(SDNode *N, unsigned Opc,
// Assign the new operands.
N->NumOperands = NumOps;
for (unsigned i = 0, e = NumOps; i != e; ++i) {
N->OperandList[i] = Ops[i];
N->OperandList[i].getSDValue() = Ops[i];
N->OperandList[i].setUser(N);
SDNode *ToUse = N->OperandList[i].getVal();
ToUse->addUser(i, N);
@ -4410,43 +4422,35 @@ void SelectionDAG::ReplaceAllUsesWith(SDValue FromN, SDValue To,
"Cannot replace with this method!");
assert(From != To.getNode() && "Cannot replace uses of with self");
// Iterate over all the existing uses of From. This specifically avoids
// visiting any new uses of From that arise while the replacement is
// happening, because any such uses would be the result of CSE: If an
// existing node looks like From after one of its operands is replaced
// by To, we don't want to replace of all its users with To too.
// See PR3018 for more info.
// Iterate over all the existing uses of From. New uses will be added
// to the beginning of the use list, which we avoid visiting.
// This specifically avoids visiting uses of From that arise while the
// replacement is happening, because any such uses would be the result
// of CSE: If an existing node looks like From after one of its operands
// is replaced by To, we don't want to replace of all its users with To
// too. See PR3018 for more info.
SDNode::use_iterator UI = From->use_begin(), UE = From->use_end();
while (UI != UE) {
SDNode *U = *UI;
do ++UI; while (UI != UE && *UI == U);
SDNode *User = *UI;
// This node is about to morph, remove its old self from the CSE maps.
RemoveNodeFromCSEMaps(U);
int operandNum = 0;
for (SDNode::op_iterator I = U->op_begin(), E = U->op_end();
I != E; ++I, ++operandNum)
if (I->getVal() == From) {
From->removeUser(operandNum, U);
*I = To;
I->setUser(U);
To.getNode()->addUser(operandNum, U);
}
RemoveNodeFromCSEMaps(User);
// 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, UpdateListener);
// U is now dead. Inform the listener if it exists and delete it.
if (UpdateListener)
UpdateListener->NodeDeleted(U, Existing);
DeleteNodeNotInCSEMaps(U);
} else {
// If the node doesn't already exist, we updated it. Inform a listener if
// it exists.
if (UpdateListener)
UpdateListener->NodeUpdated(U);
}
// A user can appear in a use list multiple times, and when this
// happens the uses are usually next to each other in the list.
// To help reduce the number of CSE recomputations, process all
// the uses of this user that we can find this way.
do {
unsigned operandNum = UI.getOperandNo();
++UI;
From->removeUser(operandNum, User);
User->OperandList[operandNum].getSDValue() = To;
To.getNode()->addUser(operandNum, User);
} while (UI != UE && *UI == User);
// Now that we have modified User, add it back to the CSE maps. If it
// already exists there, recursively merge the results together.
AddModifiedNodeToCSEMaps(User, UpdateListener);
}
}
@ -4470,34 +4474,26 @@ void SelectionDAG::ReplaceAllUsesWith(SDNode *From, SDNode *To,
// the ReplaceAllUsesWith above.
SDNode::use_iterator UI = From->use_begin(), UE = From->use_end();
while (UI != UE) {
SDNode *U = *UI;
do ++UI; while (UI != UE && *UI == U);
SDNode *User = *UI;
// This node is about to morph, remove its old self from the CSE maps.
RemoveNodeFromCSEMaps(U);
int operandNum = 0;
for (SDNode::op_iterator I = U->op_begin(), E = U->op_end();
I != E; ++I, ++operandNum)
if (I->getVal() == From) {
From->removeUser(operandNum, U);
I->getSDValue().setNode(To);
To->addUser(operandNum, U);
}
RemoveNodeFromCSEMaps(User);
// 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, UpdateListener);
// U is now dead. Inform the listener if it exists and delete it.
if (UpdateListener)
UpdateListener->NodeDeleted(U, Existing);
DeleteNodeNotInCSEMaps(U);
} else {
// If the node doesn't already exist, we updated it. Inform a listener if
// it exists.
if (UpdateListener)
UpdateListener->NodeUpdated(U);
}
// A user can appear in a use list multiple times, and when this
// happens the uses are usually next to each other in the list.
// To help reduce the number of CSE recomputations, process all
// the uses of this user that we can find this way.
do {
unsigned operandNum = UI.getOperandNo();
++UI;
From->removeUser(operandNum, User);
User->OperandList[operandNum].getSDValue().setNode(To);
To->addUser(operandNum, User);
} while (UI != UE && *UI == User);
// Now that we have modified User, add it back to the CSE maps. If it
// already exists there, recursively merge the results together.
AddModifiedNodeToCSEMaps(User, UpdateListener);
}
}
@ -4516,36 +4512,28 @@ void SelectionDAG::ReplaceAllUsesWith(SDNode *From,
// the ReplaceAllUsesWith above.
SDNode::use_iterator UI = From->use_begin(), UE = From->use_end();
while (UI != UE) {
SDNode *U = *UI;
do ++UI; while (UI != UE && *UI == U);
SDNode *User = *UI;
// This node is about to morph, remove its old self from the CSE maps.
RemoveNodeFromCSEMaps(U);
int operandNum = 0;
for (SDNode::op_iterator I = U->op_begin(), E = U->op_end();
I != E; ++I, ++operandNum)
if (I->getVal() == From) {
const SDValue &ToOp = To[I->getSDValue().getResNo()];
From->removeUser(operandNum, U);
*I = ToOp;
I->setUser(U);
ToOp.getNode()->addUser(operandNum, U);
}
RemoveNodeFromCSEMaps(User);
// 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, UpdateListener);
// U is now dead. Inform the listener if it exists and delete it.
if (UpdateListener)
UpdateListener->NodeDeleted(U, Existing);
DeleteNodeNotInCSEMaps(U);
} else {
// If the node doesn't already exist, we updated it. Inform a listener if
// it exists.
if (UpdateListener)
UpdateListener->NodeUpdated(U);
}
// A user can appear in a use list multiple times, and when this
// happens the uses are usually next to each other in the list.
// To help reduce the number of CSE recomputations, process all
// the uses of this user that we can find this way.
do {
unsigned operandNum = UI.getOperandNo();
const SDValue &ToOp =
To[User->OperandList[operandNum].getSDValue().getResNo()];
++UI;
From->removeUser(operandNum, User);
User->OperandList[operandNum].getSDValue() = ToOp;
ToOp.getNode()->addUser(operandNum, User);
} while (UI != UE && *UI == User);
// Now that we have modified User, add it back to the CSE maps. If it
// already exists there, recursively merge the results together.
AddModifiedNodeToCSEMaps(User, UpdateListener);
}
}
@ -4563,57 +4551,62 @@ void SelectionDAG::ReplaceAllUsesOfValueWith(SDValue From, SDValue To,
return;
}
// Get all of the users of From.getNode(). We want these in a nice,
// deterministically ordered and uniqued set, so we use a SmallSetVector.
SmallSetVector<SDNode*, 16> Users(From.getNode()->use_begin(), From.getNode()->use_end());
// Iterate over just the existing users of From. See the comments in
// the ReplaceAllUsesWith above.
SDNode::use_iterator UI = From.getNode()->use_begin(),
UE = From.getNode()->use_end();
while (UI != UE) {
SDNode *User = *UI;
bool UserRemovedFromCSEMaps = false;
while (!Users.empty()) {
// We know that this user uses some value of From. If it is the right
// value, update it.
SDNode *User = Users.back();
Users.pop_back();
// Scan for an operand that matches From.
SDNode::op_iterator Op = User->op_begin(), E = User->op_end();
for (; Op != E; ++Op)
if (*Op == From) break;
// If there are no matches, the user must use some other result of From.
if (Op == E) continue;
// Okay, we know this user needs to be updated. Remove its old self
// from the CSE maps.
RemoveNodeFromCSEMaps(User);
// Update all operands that match "From" in case there are multiple uses.
for (; Op != E; ++Op) {
if (*Op == From) {
From.getNode()->removeUser(Op-User->op_begin(), User);
*Op = To;
Op->setUser(User);
To.getNode()->addUser(Op-User->op_begin(), User);
// A user can appear in a use list multiple times, and when this
// happens the uses are usually next to each other in the list.
// To help reduce the number of CSE recomputations, process all
// the uses of this user that we can find this way.
do {
unsigned operandNum = UI.getOperandNo();
// Skip uses of different values from the same node.
if (User->OperandList[operandNum].getSDValue().getResNo() !=
From.getResNo()) {
++UI;
continue;
}
}
// If this node hasn't been modified yet, it's still in the CSE maps,
// so remove its old self from the CSE maps.
if (!UserRemovedFromCSEMaps) {
RemoveNodeFromCSEMaps(User);
UserRemovedFromCSEMaps = true;
}
++UI;
From.getNode()->removeUser(operandNum, User);
User->OperandList[operandNum].getSDValue() = To;
To.getNode()->addUser(operandNum, User);
} while (UI != UE && *UI == User);
// We are iterating over all uses of the From node, so if a use
// doesn't use the specific value, no changes are made.
if (!UserRemovedFromCSEMaps)
continue;
// Now that we have modified User, add it back to the CSE maps. If it
// already exists there, recursively merge the results together.
SDNode *Existing = AddNonLeafNodeToCSEMaps(User);
if (!Existing) {
if (UpdateListener) UpdateListener->NodeUpdated(User);
continue; // Continue on to next user.
}
// If there was already an existing matching node, use ReplaceAllUsesWith
// to replace the dead one with the existing one. This can cause
// recursive merging of other unrelated nodes down the line.
ReplaceAllUsesWith(User, Existing, UpdateListener);
// User is now dead. Notify a listener if present.
if (UpdateListener) UpdateListener->NodeDeleted(User, Existing);
DeleteNodeNotInCSEMaps(User);
AddModifiedNodeToCSEMaps(User, UpdateListener);
}
}
namespace {
/// UseMemo - This class is used by SelectionDAG::ReplaceAllUsesOfValuesWith
/// to record information about a use.
struct UseMemo {
SDNode *User;
unsigned Index;
unsigned operandNum;
};
}
/// ReplaceAllUsesOfValuesWith - Replace any uses of From with To, leaving
/// uses of other values produced by From.getVal() alone. The same value may
/// appear in both the From and To list. The Deleted vector is
@ -4626,57 +4619,47 @@ void SelectionDAG::ReplaceAllUsesOfValuesWith(const SDValue *From,
if (Num == 1)
return ReplaceAllUsesOfValueWith(*From, *To, UpdateListener);
SmallVector<std::pair<SDNode *, unsigned>, 16> Users;
for (unsigned i = 0; i != Num; ++i)
for (SDNode::use_iterator UI = From[i].getNode()->use_begin(),
E = From[i].getNode()->use_end(); UI != E; ++UI)
Users.push_back(std::make_pair(*UI, i));
// Read up all the uses and make records of them. This helps
// processing new uses that are introduced during the
// replacement process.
SmallVector<UseMemo, 4> Uses;
for (unsigned i = 0; i != Num; ++i) {
unsigned FromResNo = From[i].getResNo();
SDNode *FromNode = From[i].getNode();
for (SDNode::use_iterator UI = FromNode->use_begin(),
E = FromNode->use_end(); UI != E; ++UI)
if (UI.getUse().getSDValue().getResNo() == FromResNo) {
UseMemo Memo = { *UI, i, UI.getOperandNo() };
Uses.push_back(Memo);
}
}
while (!Users.empty()) {
for (unsigned UseIndex = 0, UseIndexEnd = Uses.size();
UseIndex != UseIndexEnd; ) {
// We know that this user uses some value of From. If it is the right
// value, update it.
SDNode *User = Users.back().first;
unsigned i = Users.back().second;
Users.pop_back();
// Scan for an operand that matches From.
SDNode::op_iterator Op = User->op_begin(), E = User->op_end();
for (; Op != E; ++Op)
if (*Op == From[i]) break;
// If there are no matches, the user must use some other result of From.
if (Op == E) continue;
// Okay, we know this user needs to be updated. Remove its old self
// from the CSE maps.
SDNode *User = Uses[UseIndex].User;
// This node is about to morph, remove its old self from the CSE maps.
RemoveNodeFromCSEMaps(User);
// Update all operands that match "From" in case there are multiple uses.
for (; Op != E; ++Op) {
if (*Op == From[i]) {
From[i].getNode()->removeUser(Op-User->op_begin(), User);
*Op = To[i];
Op->setUser(User);
To[i].getNode()->addUser(Op-User->op_begin(), User);
}
}
// A user can appear in a use list multiple times, and when this
// happens the uses are usually next to each other in the list.
// To help reduce the number of CSE recomputations, process all
// the uses of this user that we can find this way.
do {
unsigned i = Uses[UseIndex].Index;
unsigned operandNum = Uses[UseIndex].operandNum;
++UseIndex;
From[i].getNode()->removeUser(operandNum, User);
User->OperandList[operandNum].getSDValue() = To[i];
To[i].getNode()->addUser(operandNum, User);
} while (UseIndex != UseIndexEnd && Uses[UseIndex].User == User);
// Now that we have modified User, add it back to the CSE maps. If it
// already exists there, recursively merge the results together.
SDNode *Existing = AddNonLeafNodeToCSEMaps(User);
if (!Existing) {
if (UpdateListener) UpdateListener->NodeUpdated(User);
continue; // Continue on to next user.
}
// If there was already an existing matching node, use ReplaceAllUsesWith
// to replace the dead one with the existing one. This can cause
// recursive merging of other unrelated nodes down the line.
ReplaceAllUsesWith(User, Existing, UpdateListener);
// User is now dead. Notify a listener if present.
if (UpdateListener) UpdateListener->NodeDeleted(User, Existing);
DeleteNodeNotInCSEMaps(User);
AddModifiedNodeToCSEMaps(User, UpdateListener);
}
}