Reviewers: jarin,
Description:
[turbofan] Skip write barriers when storing smi.
On 64-bit targets, we can skip the write barrier for Store nodes if the
input is ChangeInt32ToTagged, because the value being stored is
definitely represented as a smi then.
[email protected]
Please review this at https://codereview.chromium.org/968113002/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+33, -3 lines):
M src/compiler/machine-operator-reducer.cc
M test/unittests/compiler/machine-operator-reducer-unittest.cc
Index: src/compiler/machine-operator-reducer.cc
diff --git a/src/compiler/machine-operator-reducer.cc
b/src/compiler/machine-operator-reducer.cc
index
a609a8095eb715d52fc7ceaa0a4624c492f5fb2d..8040f767f33ccd993b5199695af5ff7844c52456
100644
--- a/src/compiler/machine-operator-reducer.cc
+++ b/src/compiler/machine-operator-reducer.cc
@@ -665,10 +665,20 @@ Reduction
MachineOperatorReducer::ReduceTruncateFloat64ToInt32(Node* node) {
Reduction MachineOperatorReducer::ReduceStore(Node* node) {
- MachineType const rep =
- RepresentationOf(StoreRepresentationOf(node->op()).machine_type());
+ StoreRepresentation const store_rep = StoreRepresentationOf(node->op());
+ MachineType const rep = RepresentationOf(store_rep.machine_type());
Node* const value = node->InputAt(2);
switch (value->opcode()) {
+ case IrOpcode::kChangeInt32ToTagged: {
+ // We don't need a write barrier if we know that we're storing a smi.
+ if (machine()->Is64() &&
+ store_rep.write_barrier_kind() != kNoWriteBarrier) {
+ node->set_op(machine()->Store(
+ StoreRepresentation(store_rep.machine_type(),
kNoWriteBarrier)));
+ return Changed(node);
+ }
+ break;
+ }
case IrOpcode::kWord32And: {
Uint32BinopMatcher m(value);
if (m.right().HasValue() &&
Index: test/unittests/compiler/machine-operator-reducer-unittest.cc
diff --git a/test/unittests/compiler/machine-operator-reducer-unittest.cc
b/test/unittests/compiler/machine-operator-reducer-unittest.cc
index
9656f57090524ad8bf3600ba57046bc3c6fce1c5..85461800dfd6baca3d722b29421d41c4d537b186
100644
--- a/test/unittests/compiler/machine-operator-reducer-unittest.cc
+++ b/test/unittests/compiler/machine-operator-reducer-unittest.cc
@@ -6,6 +6,7 @@
#include "src/base/division-by-constant.h"
#include "src/compiler/js-graph.h"
#include "src/compiler/machine-operator-reducer.h"
+#include "src/compiler/simplified-operator.h"
#include "src/compiler/typer.h"
#include "test/unittests/compiler/graph-unittest.h"
#include "test/unittests/compiler/node-test-utils.h"
@@ -23,7 +24,7 @@ namespace compiler {
class MachineOperatorReducerTest : public TypedGraphTest {
public:
explicit MachineOperatorReducerTest(int num_parameters = 2)
- : TypedGraphTest(num_parameters), machine_(zone()) {}
+ : TypedGraphTest(num_parameters), machine_(zone()),
simplified_(zone()) {}
protected:
Reduction Reduce(Node* node) {
@@ -54,9 +55,11 @@ class MachineOperatorReducerTest : public TypedGraphTest
{
}
MachineOperatorBuilder* machine() { return &machine_; }
+ SimplifiedOperatorBuilder* simplified() { return &simplified_; }
private:
MachineOperatorBuilder machine_;
+ SimplifiedOperatorBuilder simplified_;
};
@@ -1503,6 +1506,23 @@ TEST_F(MachineOperatorReducerTest,
StoreRepWord16WithWord32SarAndWord32Shl) {
}
}
+
+TEST_F(MachineOperatorReducerTest, StoreWithChangeInt32ToTagged) {
+ Node* const base = Parameter(0);
+ Node* const index = Parameter(1);
+ Node* const value =
+ graph()->NewNode(simplified()->ChangeInt32ToTagged(), Parameter(2));
+ Node* const effect = graph()->start();
+ Node* const control = graph()->start();
+ Reduction const r = Reduce(graph()->NewNode(
+ machine()->Store(StoreRepresentation(kRepTagged, kFullWriteBarrier)),
+ base, index, value, effect, control));
+ ASSERT_TRUE(r.Changed());
+ EXPECT_THAT(r.replacement(),
+ IsStore(StoreRepresentation(kRepTagged, kNoWriteBarrier),
base,
+ index, value, effect, control));
+}
+
} // namespace compiler
} // namespace internal
} // namespace v8
--
--
v8-dev mailing list
[email protected]
http://groups.google.com/group/v8-dev
---
You received this message because you are subscribed to the Google Groups "v8-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/d/optout.
