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[turbofan] GraphReducer is more "fixpointish" now.

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R=jarin@chromium.org

Review URL: https://codereview.chromium.org/605933002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24236 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
bmeurer@chromium.org 2014-09-26 06:40:07 +00:00
parent 31c39284ef
commit 2f21ddfbfa
2 changed files with 5 additions and 8 deletions
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5
src/compiler/graph-reducer-unittest.cc
View File

@ -97,15 +97,16 @@ TEST_F(GraphReducerTest, ReduceOnceForEveryReducer) {
TEST_F(GraphReducerTest, ReduceAgainAfterChanged) {
Sequence s1, s2;
Sequence s1, s2, s3;
StrictMock<MockReducer> r1, r2, r3;
Node* node0 = graph()->NewNode(&OP0);
EXPECT_CALL(r1, Reduce(node0));
EXPECT_CALL(r2, Reduce(node0));
EXPECT_CALL(r3, Reduce(node0)).InSequence(s1, s2).WillOnce(
EXPECT_CALL(r3, Reduce(node0)).InSequence(s1, s2, s3).WillOnce(
Return(Reducer::Changed(node0)));
EXPECT_CALL(r1, Reduce(node0)).InSequence(s1);
EXPECT_CALL(r2, Reduce(node0)).InSequence(s2);
EXPECT_CALL(r3, Reduce(node0)).InSequence(s3);
ReduceNode(node0, &r1, &r2, &r3);
}

8
src/compiler/graph-reducer.cc
View File

@ -22,7 +22,6 @@ static bool NodeIdIsLessThan(const Node* node, NodeId id) {
void GraphReducer::ReduceNode(Node* node) {
ZoneVector<Reducer*>::iterator skip = reducers_.end();
static const unsigned kMaxAttempts = 16;
bool reduce = true;
for (unsigned attempts = 0; attempts <= kMaxAttempts; ++attempts) {
@ -31,17 +30,15 @@ void GraphReducer::ReduceNode(Node* node) {
int before = graph_->NodeCount();
for (ZoneVector<Reducer*>::iterator i = reducers_.begin();
i != reducers_.end(); ++i) {
if (i == skip) continue; // Skip this reducer.
Reduction reduction = (*i)->Reduce(node);
Node* replacement = reduction.replacement();
if (replacement == NULL) {
// No change from this reducer.
} else if (replacement == node) {
// {replacement == node} represents an in-place reduction.
// Rerun all the reducers except the current one for this node,
// as now there may be more opportunities for reduction.
// Rerun all the reducers for this node, as now there may be more
// opportunities for reduction.
reduce = true;
skip = i;
break;
} else {
if (node == graph_->start()) graph_->SetStart(replacement);
@ -63,7 +60,6 @@ void GraphReducer::ReduceNode(Node* node) {
node->Kill();
}
// Rerun all the reductions on the {replacement}.
skip = reducers_.end();
node = replacement;
reduce = true;
break;