[turbofan] Try harder to avoid write barriers when writing Smis.
This avoids write barrier when writing smis to tagged fields.
This includes writing to contexts, see example below:
var f = (function() {
var i = 0;
return function f() {
return i++; // Write barrier when writing to context.
}
})();
f(); f(); %OptimizeFunctionOnNextCall(f);
f();
Review-Url: https://codereview.chromium.org/2925793002
Cr-Commit-Position: refs/heads/master@{#45723}
diff --git a/src/compiler/simplified-lowering.cc b/src/compiler/simplified-lowering.cc
index 367a1cc..2aec9ba 100644
--- a/src/compiler/simplified-lowering.cc
+++ b/src/compiler/simplified-lowering.cc
@@ -2471,14 +2471,24 @@
}
case IrOpcode::kStoreField: {
FieldAccess access = FieldAccessOf(node->op());
- NodeInfo* input_info = GetInfo(node->InputAt(1));
+ Node* value_node = node->InputAt(1);
+ NodeInfo* input_info = GetInfo(value_node);
+ MachineRepresentation field_representation =
+ access.machine_type.representation();
+
+ // Make sure we convert to Smi if possible. This should help write
+ // barrier elimination.
+ if (field_representation == MachineRepresentation::kTagged &&
+ TypeOf(value_node)->Is(Type::SignedSmall())) {
+ field_representation = MachineRepresentation::kTaggedSigned;
+ }
WriteBarrierKind write_barrier_kind = WriteBarrierKindFor(
- access.base_is_tagged, access.machine_type.representation(),
- access.offset, access.type, input_info->representation(),
- node->InputAt(1));
+ access.base_is_tagged, field_representation, access.offset,
+ access.type, input_info->representation(), value_node);
+
ProcessInput(node, 0, UseInfoForBasePointer(access));
- ProcessInput(node, 1, TruncatingUseInfoFromRepresentation(
- access.machine_type.representation()));
+ ProcessInput(node, 1,
+ TruncatingUseInfoFromRepresentation(field_representation));
ProcessRemainingInputs(node, 2);
SetOutput(node, MachineRepresentation::kNone);
if (lower()) {
@@ -2547,15 +2557,25 @@
}
case IrOpcode::kStoreElement: {
ElementAccess access = ElementAccessOf(node->op());
- NodeInfo* input_info = GetInfo(node->InputAt(2));
+ Node* value_node = node->InputAt(2);
+ NodeInfo* input_info = GetInfo(value_node);
+ MachineRepresentation element_representation =
+ access.machine_type.representation();
+
+ // Make sure we convert to Smi if possible. This should help write
+ // barrier elimination.
+ if (element_representation == MachineRepresentation::kTagged &&
+ TypeOf(value_node)->Is(Type::SignedSmall())) {
+ element_representation = MachineRepresentation::kTaggedSigned;
+ }
WriteBarrierKind write_barrier_kind = WriteBarrierKindFor(
- access.base_is_tagged, access.machine_type.representation(),
- access.type, input_info->representation(), node->InputAt(2));
+ access.base_is_tagged, element_representation, access.type,
+ input_info->representation(), value_node);
ProcessInput(node, 0, UseInfoForBasePointer(access)); // base
ProcessInput(node, 1, UseInfo::TruncatingWord32()); // index
ProcessInput(node, 2,
TruncatingUseInfoFromRepresentation(
- access.machine_type.representation())); // value
+ element_representation)); // value
ProcessRemainingInputs(node, 3);
SetOutput(node, MachineRepresentation::kNone);
if (lower()) {