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Prevent redundant node revisit in ControlEquivalence.

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R=jarin@chromium.org

Review URL: https://codereview.chromium.org/773133003

Cr-Commit-Position: refs/heads/master@{#25638}
This commit is contained in:
mstarzinger 2014-12-03 05:24:49 -08:00 committed by Commit bot
parent 74321d5558
commit 740d0a987a
1 changed files with 7 additions and 4 deletions
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11
src/compiler/control-equivalence.h
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@ -87,6 +87,7 @@ class ControlEquivalence : public ZoneObject {
struct NodeData {
size_t class_number; // Equivalence class number assigned to node.
size_t dfs_number; // Pre-order DFS number assigned to node.
bool visited; // Indicates node has already been visited.
bool on_stack; // Indicates node is on DFS stack during walk.
bool participates; // Indicates node participates in DFS walk.
BracketList blist; // List of brackets per node.
@ -114,9 +115,8 @@ class ControlEquivalence : public ZoneObject {
// Potentially introduce artificial dependency from start to end.
if (blist.empty()) {
DCHECK_EQ(graph_->start(), node);
DCHECK_EQ(kInputDirection, direction);
VisitBackedge(graph_->start(), graph_->end(), kInputDirection);
VisitBackedge(node, graph_->end(), kInputDirection);
}
// Potentially start a new equivalence class [line:37].
@ -189,6 +189,7 @@ class ControlEquivalence : public ZoneObject {
NodeProperties::IsControl(input)) {
// Visit next control input.
if (!GetData(input)->participates) continue;
if (GetData(input)->visited) continue;
if (GetData(input)->on_stack) {
// Found backedge if input is on stack.
if (input != entry.parent_node) {
@ -219,6 +220,7 @@ class ControlEquivalence : public ZoneObject {
NodeProperties::IsControl(use)) {
// Visit next control use.
if (!GetData(use)->participates) continue;
if (GetData(use)->visited) continue;
if (GetData(use)->on_stack) {
// Found backedge if use is on stack.
if (use != entry.parent_node) {
@ -275,7 +277,7 @@ class ControlEquivalence : public ZoneObject {
// Template used to initialize per-node data.
NodeData EmptyData() {
return {kInvalidClass, 0, false, false, BracketList(zone_)};
return {kInvalidClass, 0, false, false, false, BracketList(zone_)};
}
// Accessors for the DFS number stored within the per-node data.
@ -299,6 +301,7 @@ class ControlEquivalence : public ZoneObject {
// Mutates the DFS stack by pushing an entry.
void DFSPush(DFSStack& stack, Node* node, Node* from, DFSDirection dir) {
DCHECK(GetData(node)->participates);
DCHECK(!GetData(node)->visited);
GetData(node)->on_stack = true;
Node::InputEdges::iterator input = node->input_edges().begin();
Node::UseEdges::iterator use = node->use_edges().begin();
@ -309,7 +312,7 @@ class ControlEquivalence : public ZoneObject {
void DFSPop(DFSStack& stack, Node* node) {
DCHECK_EQ(stack.top().node, node);
GetData(node)->on_stack = false;
GetData(node)->participates = false;
GetData(node)->visited = true;
stack.pop();
}