Reviewers: jarin,
Description:
Revert "[turbofan] Fix select lowering."
This reverts commit cf08e8d70ff0fa35dd315ddc430b743bb04c89cf for
breaking Embenchen bullet.
[email protected]
Please review this at https://codereview.chromium.org/684413003/
Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+15, -61 lines):
M src/compiler/node.h
M src/compiler/select-lowering.h
M src/compiler/select-lowering.cc
M test/unittests/compiler/select-lowering-unittest.cc
Index: src/compiler/node.h
diff --git a/src/compiler/node.h b/src/compiler/node.h
index
8a442cedbc7aed407eda1e7f88d6388df58cdba3..3a5afd25dad800d070a901eecce8ca2591b0c7e8
100644
--- a/src/compiler/node.h
+++ b/src/compiler/node.h
@@ -68,8 +68,6 @@ typedef std::set<Node*, std::less<Node*>,
zone_allocator<Node*> > NodeSet;
typedef NodeSet::iterator NodeSetIter;
typedef NodeSet::reverse_iterator NodeSetRIter;
-typedef ZoneDeque<Node*> NodeDeque;
-
typedef ZoneVector<Node*> NodeVector;
typedef NodeVector::iterator NodeVectorIter;
typedef NodeVector::const_iterator NodeVectorConstIter;
Index: src/compiler/select-lowering.cc
diff --git a/src/compiler/select-lowering.cc
b/src/compiler/select-lowering.cc
index
44d040df046dbaf504706fa7cfa7b6490fa1d945..2e51d72024bb8f96e3f82850352b132c682209bd
100644
--- a/src/compiler/select-lowering.cc
+++ b/src/compiler/select-lowering.cc
@@ -26,58 +26,26 @@ Reduction SelectLowering::Reduce(Node* node) {
if (node->opcode() != IrOpcode::kSelect) return NoChange();
SelectParameters const p = SelectParametersOf(node->op());
- Node* cond = node->InputAt(0);
- Node* vthen = node->InputAt(1);
- Node* velse = node->InputAt(2);
- Node* merge = nullptr;
+ Node* const cond = node->InputAt(0);
// Check if we already have a diamond for this condition.
- auto range = merges_.equal_range(cond);
- for (auto i = range.first;; ++i) {
- if (i == range.second) {
- // Create a new diamond for this condition and remember its merge
node.
- Diamond d(graph(), common(), cond, p.hint());
- merges_.insert(std::make_pair(cond, d.merge));
- merge = d.merge;
- break;
- }
-
- // If the diamond is reachable from the Select, merging them would
result in
- // an unschedulable graph, so we cannot reuse the diamond in that case.
- merge = i->second;
- if (!ReachableFrom(merge, node)) {
- break;
- }
+ auto i = merges_.find(cond);
+ if (i == merges_.end()) {
+ // Create a new diamond for this condition and remember its merge node.
+ Diamond d(graph(), common(), cond, p.hint());
+ i = merges_.insert(std::make_pair(cond, d.merge)).first;
}
+ DCHECK_EQ(cond, i->first);
+
// Create a Phi hanging off the previously determined merge.
node->set_op(common()->Phi(p.type(), 2));
- node->ReplaceInput(0, vthen);
- node->ReplaceInput(1, velse);
- node->ReplaceInput(2, merge);
+ node->ReplaceInput(0, node->InputAt(1));
+ node->ReplaceInput(1, node->InputAt(2));
+ node->ReplaceInput(2, i->second);
return Changed(node);
}
-
-bool SelectLowering::ReachableFrom(Node* const sink, Node* const source) {
- // TODO(turbofan): This is probably horribly expensive, and it should be
moved
- // into node.h or somewhere else?!
- Zone zone(graph()->zone()->isolate());
- std::queue<Node*, NodeDeque> pending((NodeDeque(&zone)));
- BoolVector visited(graph()->NodeCount(), false, &zone);
- pending.push(source);
- while (!pending.empty()) {
- Node* current = pending.front();
- if (current == sink) return true;
- pending.pop();
- visited[current->id()] = true;
- for (auto input : current->inputs()) {
- if (!visited[input->id()]) pending.push(input);
- }
- }
- return false;
-}
-
} // namespace compiler
} // namespace internal
} // namespace v8
Index: src/compiler/select-lowering.h
diff --git a/src/compiler/select-lowering.h b/src/compiler/select-lowering.h
index
05ea0e0c75869c8063362cef35276fbb70491daf..ae22cade84420584cd21bb41140b343c51213c33
100644
--- a/src/compiler/select-lowering.h
+++ b/src/compiler/select-lowering.h
@@ -28,10 +28,8 @@ class SelectLowering FINAL : public Reducer {
Reduction Reduce(Node* node) OVERRIDE;
private:
- typedef std::multimap<Node*, Node*, std::less<Node*>,
- zone_allocator<std::pair<Node* const, Node*>>>
Merges;
-
- bool ReachableFrom(Node* const sink, Node* const source);
+ typedef std::map<Node*, Node*, std::less<Node*>,
+ zone_allocator<std::pair<Node* const, Node*>>> Merges;
CommonOperatorBuilder* common() const { return common_; }
Graph* graph() const { return graph_; }
Index: test/unittests/compiler/select-lowering-unittest.cc
diff --git a/test/unittests/compiler/select-lowering-unittest.cc
b/test/unittests/compiler/select-lowering-unittest.cc
index
51efc83f87c2eb15d4d8f6edfe3ac3a7ef77a34b..6dbd7ad73d99608931c8a6d06c1781b656b38bd3
100644
--- a/test/unittests/compiler/select-lowering-unittest.cc
+++ b/test/unittests/compiler/select-lowering-unittest.cc
@@ -10,7 +10,6 @@
using testing::AllOf;
using testing::Capture;
using testing::CaptureEq;
-using testing::Not;
namespace v8 {
namespace internal {
@@ -34,12 +33,12 @@ TEST_F(SelectLoweringTest, SelectWithSameConditions) {
Node* const p2 = Parameter(2);
Node* const p3 = Parameter(3);
Node* const p4 = Parameter(4);
- Node* const s0 = graph()->NewNode(common()->Select(kMachInt32), p0, p1,
p2);
Capture<Node*> branch;
Capture<Node*> merge;
{
- Reduction const r = Reduce(s0);
+ Reduction const r =
+ Reduce(graph()->NewNode(common()->Select(kMachInt32), p0, p1, p2));
ASSERT_TRUE(r.Changed());
EXPECT_THAT(
r.replacement(),
@@ -56,15 +55,6 @@ TEST_F(SelectLoweringTest, SelectWithSameConditions) {
ASSERT_TRUE(r.Changed());
EXPECT_THAT(r.replacement(), IsPhi(kMachInt32, p3, p4,
CaptureEq(&merge)));
}
- {
- // We must not reuse the diamond if it is reachable from either
else/then
- // values of the Select, because the resulting graph can not be
scheduled.
- Reduction const r =
- Reduce(graph()->NewNode(common()->Select(kMachInt32), p0, s0, p0));
- ASSERT_TRUE(r.Changed());
- EXPECT_THAT(r.replacement(),
- IsPhi(kMachInt32, s0, p0, Not(CaptureEq(&merge))));
- }
}
} // namespace compiler
--
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