[llvm] 1d2b6d9 - [Support] Use block numbers for DomTree construction (#101706)
via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 6 09:23:06 PDT 2024
Author: Alexis Engelke
Date: 2024-08-06T18:23:01+02:00
New Revision: 1d2b6d9d4d1074bac4a6ec48dd0ff4253590e34a
URL: https://github.com/llvm/llvm-project/commit/1d2b6d9d4d1074bac4a6ec48dd0ff4253590e34a
DIFF: https://github.com/llvm/llvm-project/commit/1d2b6d9d4d1074bac4a6ec48dd0ff4253590e34a.diff
LOG: [Support] Use block numbers for DomTree construction (#101706)
Similar to #101705, do the same optimization for dominator tree
construction.
Added:
Modified:
llvm/include/llvm/ADT/GraphTraits.h
llvm/include/llvm/Support/GenericDomTreeConstruction.h
Removed:
################################################################################
diff --git a/llvm/include/llvm/ADT/GraphTraits.h b/llvm/include/llvm/ADT/GraphTraits.h
index 69f9facebefe7..0764ecb4bb568 100644
--- a/llvm/include/llvm/ADT/GraphTraits.h
+++ b/llvm/include/llvm/ADT/GraphTraits.h
@@ -19,6 +19,7 @@
#ifndef LLVM_ADT_GRAPHTRAITS_H
#define LLVM_ADT_GRAPHTRAITS_H
+#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/iterator_range.h"
namespace llvm {
@@ -94,6 +95,16 @@ struct GraphTraits {
using NodeRef = typename GraphType::UnknownGraphTypeError;
};
+namespace detail {
+template <typename T>
+using has_number_t = decltype(GraphTraits<T>::getNumber(std::declval<T>()));
+} // namespace detail
+
+/// Indicate whether a GraphTraits<NodeT>::getNumber() is supported.
+template <typename NodeT>
+constexpr bool GraphHasNodeNumbers =
+ is_detected<detail::has_number_t, NodeT>::value;
+
// Inverse - This class is used as a little marker class to tell the graph
// iterator to iterate over the graph in a graph defined "Inverse" ordering.
// Not all graphs define an inverse ordering, and if they do, it depends on
diff --git a/llvm/include/llvm/Support/GenericDomTreeConstruction.h b/llvm/include/llvm/Support/GenericDomTreeConstruction.h
index 21ab042251c25..9aab5ec60f4a2 100644
--- a/llvm/include/llvm/Support/GenericDomTreeConstruction.h
+++ b/llvm/include/llvm/Support/GenericDomTreeConstruction.h
@@ -73,7 +73,11 @@ struct SemiNCAInfo {
// Number to node mapping is 1-based. Initialize the mapping to start with
// a dummy element.
SmallVector<NodePtr, 64> NumToNode = {nullptr};
- DenseMap<NodePtr, InfoRec> NodeToInfo;
+ // If blocks have numbers (e.g., BasicBlock, MachineBasicBlock), store node
+ // infos in a vector. Otherwise, store them in a map.
+ std::conditional_t<GraphHasNodeNumbers<NodePtr>, SmallVector<InfoRec, 64>,
+ DenseMap<NodePtr, InfoRec>>
+ NodeInfos;
using UpdateT = typename DomTreeT::UpdateType;
using UpdateKind = typename DomTreeT::UpdateKind;
@@ -99,7 +103,7 @@ struct SemiNCAInfo {
void clear() {
NumToNode = {nullptr}; // Restore to initial state with a dummy start node.
- NodeToInfo.clear();
+ NodeInfos.clear();
// Don't reset the pointer to BatchUpdateInfo here -- if there's an update
// in progress, we need this information to continue it.
}
@@ -123,13 +127,25 @@ struct SemiNCAInfo {
return Res;
}
- NodePtr getIDom(NodePtr BB) const {
- auto InfoIt = NodeToInfo.find(BB);
- if (InfoIt == NodeToInfo.end()) return nullptr;
-
- return InfoIt->second.IDom;
+ InfoRec &getNodeInfo(NodePtr BB) {
+ if constexpr (GraphHasNodeNumbers<NodePtr>) {
+ unsigned Idx = BB ? GraphTraits<NodePtr>::getNumber(BB) + 1 : 0;
+ if (Idx >= NodeInfos.size()) {
+ unsigned Max = 0;
+ if (BB)
+ Max = GraphTraits<decltype(BB->getParent())>::getMaxNumber(
+ BB->getParent());
+ // Max might be zero, graphs might not support getMaxNumber().
+ NodeInfos.resize(Max ? Max + 1 : Idx + 1);
+ }
+ return NodeInfos[Idx];
+ } else {
+ return NodeInfos[BB];
+ }
}
+ NodePtr getIDom(NodePtr BB) { return getNodeInfo(BB).IDom; }
+
TreeNodePtr getNodeForBlock(NodePtr BB, DomTreeT &DT) {
if (TreeNodePtr Node = DT.getNode(BB)) return Node;
@@ -181,11 +197,11 @@ struct SemiNCAInfo {
const NodeOrderMap *SuccOrder = nullptr) {
assert(V);
SmallVector<std::pair<NodePtr, unsigned>, 64> WorkList = {{V, AttachToNum}};
- NodeToInfo[V].Parent = AttachToNum;
+ getNodeInfo(V).Parent = AttachToNum;
while (!WorkList.empty()) {
const auto [BB, ParentNum] = WorkList.pop_back_val();
- auto &BBInfo = NodeToInfo[BB];
+ auto &BBInfo = getNodeInfo(BB);
BBInfo.ReverseChildren.push_back(ParentNum);
// Visited nodes always have positive DFS numbers.
@@ -264,7 +280,7 @@ struct SemiNCAInfo {
// Initialize IDoms to spanning tree parents.
for (unsigned i = 1; i < NextDFSNum; ++i) {
const NodePtr V = NumToNode[i];
- auto &VInfo = NodeToInfo[V];
+ auto &VInfo = getNodeInfo(V);
VInfo.IDom = NumToNode[VInfo.Parent];
NumToInfo.push_back(&VInfo);
}
@@ -292,7 +308,7 @@ struct SemiNCAInfo {
const unsigned SDomNum = NumToInfo[WInfo.Semi]->DFSNum;
NodePtr WIDomCandidate = WInfo.IDom;
while (true) {
- auto &WIDomCandidateInfo = NodeToInfo.find(WIDomCandidate)->second;
+ auto &WIDomCandidateInfo = getNodeInfo(WIDomCandidate);
if (WIDomCandidateInfo.DFSNum <= SDomNum)
break;
WIDomCandidate = WIDomCandidateInfo.IDom;
@@ -311,7 +327,7 @@ struct SemiNCAInfo {
assert(IsPostDom && "Only postdominators have a virtual root");
assert(NumToNode.size() == 1 && "SNCAInfo must be freshly constructed");
- auto &BBInfo = NodeToInfo[nullptr];
+ auto &BBInfo = getNodeInfo(nullptr);
BBInfo.DFSNum = BBInfo.Semi = BBInfo.Label = 1;
NumToNode.push_back(nullptr); // NumToNode[1] = nullptr;
@@ -393,7 +409,7 @@ struct SemiNCAInfo {
auto InitSuccOrderOnce = [&]() {
SuccOrder = NodeOrderMap();
for (const auto Node : nodes(DT.Parent))
- if (SNCA.NodeToInfo.count(Node) == 0)
+ if (SNCA.getNodeInfo(Node).DFSNum == 0)
for (const auto Succ : getChildren<false>(Node, SNCA.BatchUpdates))
SuccOrder->try_emplace(Succ, 0);
@@ -417,7 +433,7 @@ struct SemiNCAInfo {
// unreachable node once, we may just visit it in two directions,
// depending on how lucky we get.
for (const NodePtr I : nodes(DT.Parent)) {
- if (SNCA.NodeToInfo.count(I) == 0) {
+ if (SNCA.getNodeInfo(I).DFSNum == 0) {
LLVM_DEBUG(dbgs()
<< "\t\t\tVisiting node " << BlockNamePrinter(I) << "\n");
// Find the furthest away we can get by following successors, then
@@ -449,7 +465,7 @@ struct SemiNCAInfo {
const NodePtr N = SNCA.NumToNode[i];
LLVM_DEBUG(dbgs() << "\t\t\t\tRemoving DFS info for "
<< BlockNamePrinter(N) << "\n");
- SNCA.NodeToInfo.erase(N);
+ SNCA.getNodeInfo(N) = {};
SNCA.NumToNode.pop_back();
}
const unsigned PrevNum = Num;
@@ -582,7 +598,7 @@ struct SemiNCAInfo {
void attachNewSubtree(DomTreeT& DT, const TreeNodePtr AttachTo) {
// Attach the first unreachable block to AttachTo.
- NodeToInfo[NumToNode[1]].IDom = AttachTo->getBlock();
+ getNodeInfo(NumToNode[1]).IDom = AttachTo->getBlock();
// Loop over all of the discovered blocks in the function...
for (NodePtr W : llvm::drop_begin(NumToNode)) {
if (DT.getNode(W))
@@ -600,11 +616,11 @@ struct SemiNCAInfo {
}
void reattachExistingSubtree(DomTreeT &DT, const TreeNodePtr AttachTo) {
- NodeToInfo[NumToNode[1]].IDom = AttachTo->getBlock();
+ getNodeInfo(NumToNode[1]).IDom = AttachTo->getBlock();
for (const NodePtr N : llvm::drop_begin(NumToNode)) {
const TreeNodePtr TN = DT.getNode(N);
assert(TN);
- const TreeNodePtr NewIDom = DT.getNode(NodeToInfo[N].IDom);
+ const TreeNodePtr NewIDom = DT.getNode(getNodeInfo(N).IDom);
TN->setIDom(NewIDom);
}
}
@@ -1239,7 +1255,7 @@ struct SemiNCAInfo {
// Virtual root has a corresponding virtual CFG node.
if (DT.isVirtualRoot(TN)) continue;
- if (NodeToInfo.count(BB) == 0) {
+ if (getNodeInfo(BB).DFSNum == 0) {
errs() << "DomTree node " << BlockNamePrinter(BB)
<< " not found by DFS walk!\n";
errs().flush();
@@ -1453,7 +1469,7 @@ struct SemiNCAInfo {
});
for (TreeNodePtr Child : TN->children())
- if (NodeToInfo.count(Child->getBlock()) != 0) {
+ if (getNodeInfo(Child->getBlock()).DFSNum != 0) {
errs() << "Child " << BlockNamePrinter(Child)
<< " reachable after its parent " << BlockNamePrinter(BB)
<< " is removed!\n";
@@ -1491,7 +1507,7 @@ struct SemiNCAInfo {
for (const TreeNodePtr S : TN->children()) {
if (S == N) continue;
- if (NodeToInfo.count(S->getBlock()) == 0) {
+ if (getNodeInfo(S->getBlock()).DFSNum == 0) {
errs() << "Node " << BlockNamePrinter(S)
<< " not reachable when its sibling " << BlockNamePrinter(N)
<< " is removed!\n";
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