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[Explicit State Access] Guard state_read reference from Next in nodes.cc #4559

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Merged
copybara-service merged 1 commit into from
Jul 16, 2026
+45 −3
Merged

[Explicit State Access] Guard state_read reference from Next in nodes.cc #4559

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13 changes: 10 additions & 3 deletions xls/ir/nodes.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -985,9 +985,16 @@ bool StateRead::IsDefinitelyEqualTo(const Node* other) const {

std::vector<Next*> StateRead::GetNextValues() const {
std::vector<Next*> next_values;
for (Node* user : users()) {
if (user->Is<Next>() && user->As<Next>()->state_read() == this) {
next_values.push_back(user->As<Next>());
if (function_base()->AsProcOrDie()->uses_decoupled_next()) {
const auto& next_values_se =
function_base()->AsProcOrDie()->next_values(state_element_);
next_values.insert(next_values.end(), next_values_se.begin(),
next_values_se.end());
} else {
for (Node* user : users()) {
if (user->Is<Next>() && user->As<Next>()->state_read() == this) {
next_values.push_back(user->As<Next>());
}
}
}
return next_values;
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35 changes: 35 additions & 0 deletions xls/ir/proc_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -288,6 +288,41 @@ TEST_F(ProcTest, RemoveStateThatStillHasUse) {
HasSubstr("state read st has uses")));
}

TEST_F(ProcTest, GetNextStateReadDecoupled) {
auto p = CreatePackage();
TokenlessProcBuilder pb(TestName(), "tkn", p.get());
XLS_ASSERT_OK_AND_ASSIGN(StateElement * state_elem,
pb.UnreadStateElement("x", Value(UBits(42, 32)),
/*non_synthesizable=*/false));
BValue read = pb.StateRead(state_elem);
BValue next_val = pb.Add(read, pb.Literal(Value(UBits(1, 32))));
XLS_ASSERT_OK_AND_ASSIGN(Proc * proc, pb.Build({}));

StateRead* state_read = proc->GetStateReadByStateElement(state_elem);
EXPECT_EQ(state_read->GetNextValues().size(), 0);

XLS_ASSERT_OK(proc->MakeNodeWithName<Next>(SourceInfo(), state_elem,
next_val.node(),
/*predicate=*/std::nullopt,
/*label=*/std::nullopt, "x_next")
.status());
EXPECT_EQ(state_read->GetNextValues().size(), 1);

XLS_ASSERT_OK_AND_ASSIGN(
Literal * next_value,
proc->MakeNode<Literal>(SourceInfo(), Value(UBits(43, 32))));
XLS_ASSERT_OK(
proc->MakeNodeWithName<Next>(SourceInfo(), state_elem, next_value,
/*predicate=*/std::nullopt,
/*label=*/std::nullopt, "second_next")
.status());
EXPECT_EQ(state_read->GetNextValues().size(), 2);
EXPECT_THAT(state_read->GetNextValues(),
UnorderedElementsAre(
m::NextWithStateElement(state_elem, m::Add()),
m::NextWithStateElement(state_elem, m::Literal(43))));
}

TEST_F(ProcTest, InsertStateElementDecoupled) {
auto p = CreatePackage();
ProcBuilder pb("p", p.get());
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