[llvm-commits] [llvm] r56867 - in /llvm/trunk: include/llvm/CodeGen/DAGISelHeader.h include/llvm/CodeGen/SelectionDAG.h include/llvm/CodeGen/SelectionDAGISel.h lib/CodeGen/SelectionDAG/LegalizeDAG.cpp lib/CodeGen/SelectionDAG/SelectionDAG.cpp lib/Target/X86/X86ISelDAGToDAG.cpp
Dan Gohman
gohman at apple.com
Tue Sep 30 11:30:37 PDT 2008
Author: djg
Date: Tue Sep 30 13:30:35 2008
New Revision: 56867
URL: http://llvm.org/viewvc/llvm-project?rev=56867&view=rev
Log:
Optimize SelectionDAG's AssignTopologicalOrder even further.
Completely eliminate the TopOrder std::vector. Instead, sort
the AllNodes list in place. This also eliminates the need to
call AllNodes.size(), a linear-time operation, before
performing the sort.
Also, eliminate the Sources temporary std::vector, since it
essentially duplicates the sorted result as it is being
built.
This also changes the direction of the topological sort
from bottom-up to top-down. The AllNodes list starts out in
roughly top-down order, so this reduces the amount of
reordering needed. Top-down is also more convenient for
Legalize, and ISel needed only minor adjustments.
Modified:
llvm/trunk/include/llvm/CodeGen/DAGISelHeader.h
llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h
llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
Modified: llvm/trunk/include/llvm/CodeGen/DAGISelHeader.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/DAGISelHeader.h?rev=56867&r1=56866&r2=56867&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/DAGISelHeader.h (original)
+++ llvm/trunk/include/llvm/CodeGen/DAGISelHeader.h Tue Sep 30 13:30:35 2008
@@ -18,7 +18,7 @@
#define LLVM_CODEGEN_DAGISEL_HEADER_H
/// ISelQueue - Instruction selector priority queue sorted
-/// in the order of increasing NodeId() values.
+/// in the order of decreasing NodeId() values.
std::vector<SDNode*> ISelQueue;
/// Keep track of nodes which have already been added to queue.
@@ -43,10 +43,10 @@
}
/// isel_sort - Sorting functions for the selection queue in the
-/// increasing NodeId order.
+/// decreasing NodeId order.
struct isel_sort : public std::binary_function<SDNode*, SDNode*, bool> {
bool operator()(const SDNode* left, const SDNode* right) const {
- return (left->getNodeId() > right->getNodeId());
+ return left->getNodeId() < right->getNodeId();
}
};
@@ -108,7 +108,7 @@
};
/// UpdateQueue - update the instruction selction queue to maintain
-/// the increasing NodeId() ordering property.
+/// the decreasing NodeId() ordering property.
inline void UpdateQueue(const ISelQueueUpdater &ISQU) {
if (ISQU.hadDelete())
std::make_heap(ISelQueue.begin(), ISelQueue.end(),isel_sort());
Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAG.h?rev=56867&r1=56866&r2=56867&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAG.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAG.h Tue Sep 30 13:30:35 2008
@@ -663,10 +663,10 @@
unsigned Num,
DAGUpdateListener *UpdateListener = 0);
- /// AssignTopologicalOrder - Assign a unique node id for each node in the DAG
- /// based on their topological order. It returns the maximum id and a vector
- /// of the SDNodes* in assigned order by reference.
- unsigned AssignTopologicalOrder(std::vector<SDNode*> &TopOrder);
+ /// AssignTopologicalOrder - Topological-sort the AllNodes list and a
+ /// assign a unique node id for each node in the DAG based on their
+ /// topological order. Returns the number of nodes.
+ unsigned AssignTopologicalOrder();
/// isCommutativeBinOp - Returns true if the opcode is a commutative binary
/// operation.
Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h?rev=56867&r1=56866&r2=56867&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h Tue Sep 30 13:30:35 2008
@@ -48,7 +48,6 @@
AliasAnalysis *AA;
GCFunctionInfo *GFI;
bool Fast;
- std::vector<SDNode*> TopOrder;
static char ID;
explicit SelectionDAGISel(TargetLowering &tli, bool fast = false);
@@ -67,7 +66,7 @@
virtual void InstructionSelectPostProcessing() {}
void SelectRootInit() {
- DAGSize = CurDAG->AssignTopologicalOrder(TopOrder);
+ DAGSize = CurDAG->AssignTopologicalOrder();
}
/// SelectInlineAsmMemoryOperand - Select the specified address as a target
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp?rev=56867&r1=56866&r2=56867&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp Tue Sep 30 13:30:35 2008
@@ -280,11 +280,10 @@
// practice however, this causes us to run out of stack space on large basic
// blocks. To avoid this problem, compute an ordering of the nodes where each
// node is only legalized after all of its operands are legalized.
- std::vector<SDNode *> TopOrder;
- unsigned N = DAG.AssignTopologicalOrder(TopOrder);
- for (unsigned i = N; i != 0; --i)
- HandleOp(SDValue(TopOrder[i-1], 0));
- TopOrder.clear();
+ DAG.AssignTopologicalOrder();
+ for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
+ E = prior(DAG.allnodes_end()); I != next(E); ++I)
+ HandleOp(SDValue(I, 0));
// Finally, it's possible the root changed. Get the new root.
SDValue OldRoot = DAG.getRoot();
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=56867&r1=56866&r2=56867&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Tue Sep 30 13:30:35 2008
@@ -587,7 +587,7 @@
void SelectionDAG::DeleteNodeNotInCSEMaps(SDNode *N) {
- // Drop all of the operands and decrement used nodes use counts.
+ // Drop all of the operands and decrement used node's use counts.
for (SDNode::op_iterator I = N->op_begin(), E = N->op_end(); I != E; ++I)
I->getVal()->removeUser(std::distance(N->op_begin(), I), N);
if (N->OperandsNeedDelete)
@@ -4569,38 +4569,74 @@
/// AssignTopologicalOrder - Assign a unique node id for each node in the DAG
/// based on their topological order. It returns the maximum id and a vector
/// of the SDNodes* in assigned order by reference.
-unsigned SelectionDAG::AssignTopologicalOrder(std::vector<SDNode*> &TopOrder) {
- unsigned DAGSize = AllNodes.size();
- std::vector<SDNode*> Sources;
+unsigned SelectionDAG::AssignTopologicalOrder() {
- for (allnodes_iterator I = allnodes_begin(),E = allnodes_end(); I != E; ++I){
+ unsigned DAGSize = 0;
+
+ // SortedPos tracks the progress of the algorithm. Nodes before it are
+ // sorted, nodes after it are unsorted. When the algorithm completes
+ // it is at the end of the list.
+ allnodes_iterator SortedPos = allnodes_begin();
+
+ // Visit all the nodes. Add nodes with no operands to the TopOrder result
+ // array immediately. Annotate nodes that do have operands with their
+ // operand count. Before we do this, the Node Id fields of the nodes
+ // may contain arbitrary values. After, the Node Id fields for nodes
+ // before SortedPos will contain the topological sort index, and the
+ // Node Id fields for nodes At SortedPos and after will contain the
+ // count of outstanding operands.
+ for (allnodes_iterator I = allnodes_begin(),E = allnodes_end(); I != E; ) {
+ SDNode *N = I++;
+ unsigned Degree = N->getNumOperands();
+ if (Degree == 0) {
+ // A node with no uses, add it to the result array immediately.
+ N->setNodeId(DAGSize++);
+ allnodes_iterator Q = N;
+ if (Q != SortedPos)
+ SortedPos = AllNodes.insert(SortedPos, AllNodes.remove(Q));
+ ++SortedPos;
+ } else {
+ // Temporarily use the Node Id as scratch space for the degree count.
+ N->setNodeId(Degree);
+ }
+ }
+
+ // Visit all the nodes. As we iterate, moves nodes into sorted order,
+ // such that by the time the end is reached all nodes will be sorted.
+ for (allnodes_iterator I = allnodes_begin(),E = allnodes_end(); I != E; ++I) {
SDNode *N = I;
- unsigned Degree = N->use_size();
- // Temporarily use the Node Id as scratch space for the degree count.
- N->setNodeId(Degree);
- if (Degree == 0)
- Sources.push_back(N);
- }
-
- TopOrder.clear();
- TopOrder.reserve(DAGSize);
- int Id = 0;
- while (!Sources.empty()) {
- SDNode *N = Sources.back();
- Sources.pop_back();
- TopOrder.push_back(N);
- N->setNodeId(Id++);
- for (SDNode::op_iterator I = N->op_begin(), E = N->op_end(); I != E; ++I) {
- SDNode *P = I->getVal();
+ for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
+ UI != UE; ++UI) {
+ SDNode *P = *UI;
unsigned Degree = P->getNodeId();
--Degree;
- P->setNodeId(Degree);
- if (Degree == 0)
- Sources.push_back(P);
+ if (Degree == 0) {
+ // All of P's operands are sorted, so P may sorted now.
+ P->setNodeId(DAGSize++);
+ if (P != SortedPos)
+ SortedPos = AllNodes.insert(SortedPos, AllNodes.remove(P));
+ ++SortedPos;
+ } else {
+ // Update P's outstanding operand count.
+ P->setNodeId(Degree);
+ }
}
}
- return Id;
+ assert(SortedPos == AllNodes.end() &&
+ "Topological sort incomplete!");
+ assert(AllNodes.front().getOpcode() == ISD::EntryToken &&
+ "First node in topological sort is not the entry token!");
+ assert(AllNodes.front().getNodeId() == 0 &&
+ "First node in topological sort has non-zero id!");
+ assert(AllNodes.front().getNumOperands() == 0 &&
+ "First node in topological sort has operands!");
+ assert(AllNodes.back().getNodeId() == (int)DAGSize-1 &&
+ "Last node in topologic sort has unexpected id!");
+ assert(AllNodes.back().use_empty() &&
+ "Last node in topologic sort has users!");
+ assert(DAGSize == allnodes_size() && "TopOrder result count mismatch!");
+ return DAGSize;
}
Modified: llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp?rev=56867&r1=56866&r2=56867&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp Tue Sep 30 13:30:35 2008
@@ -269,7 +269,7 @@
SDNode *Root, bool &found,
SmallPtrSet<SDNode*, 16> &Visited) {
if (found ||
- Use->getNodeId() > Def->getNodeId() ||
+ Use->getNodeId() < Def->getNodeId() ||
!Visited.insert(Use))
return;
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