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[Explicit State Access] Guard state_read reference from Next in run_pipeline_schedule.cc #4560

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Merged
copybara-service merged 1 commit into from
Jul 16, 2026
+42 −1
Merged

[Explicit State Access] Guard state_read reference from Next in run_pipeline_schedule.cc #4560

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38 changes: 38 additions & 0 deletions xls/scheduling/pipeline_schedule_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -2372,6 +2372,44 @@ TEST_P(PipelineScheduleTest, ProcWithMultipleStateReads) {
EXPECT_EQ(schedule.length(), 1);
}

TEST_P(PipelineScheduleTest, ProcDecoupledFindMinimumCaseThroughput) {
Package p(TestName());
Type* u32 = p.GetBitsType(32);
XLS_ASSERT_OK_AND_ASSIGN(
Channel * out_ch,
p.CreateStreamingChannel("out_ch", ChannelOps::kSendOnly, u32));

TokenlessProcBuilder pb("the_proc", "tkn", &p);
XLS_ASSERT_OK_AND_ASSIGN(StateElement * se,
pb.UnreadStateElement("state", Value(UBits(0, 32)),
/*non_synthesizable=*/false));
BValue current = pb.StateRead(se);
BValue first_add = pb.Add(current, pb.Literal(UBits(1, 32)));
BValue second_add = pb.Add(first_add, pb.Literal(UBits(2, 32)));
BValue third_add = pb.Add(second_add, pb.Literal(UBits(3, 32)));

pb.Send(out_ch, third_add);
BValue next = pb.Next(se, third_add);

XLS_ASSERT_OK_AND_ASSIGN(Proc * proc, pb.Build());

SchedulingOptions options = this->options();
options.clock_period_ps(1);
options.minimize_worst_case_throughput(true);

XLS_ASSERT_OK_AND_ASSIGN(
PipelineSchedule schedule,
RunPipelineSchedule(proc, TestDelayEstimator(), options));
EXPECT_EQ(schedule.cycle(current.node()), 0);
EXPECT_EQ(schedule.cycle(next.node()), 2);

ASSERT_TRUE(proc->GetInitiationInterval().has_value());
EXPECT_EQ(proc->GetInitiationInterval().value(), 3);

EXPECT_LE(schedule.cycle(next.node()) - schedule.cycle(current.node()),
*proc->GetInitiationInterval() - 1);
}

TEST_P(PipelineScheduleErrorTest, ProcWithZeroReadsErrors) {
Package p(TestName());
TokenlessProcBuilder pb("the_proc", "tkn", &p);
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5 changes: 4 additions & 1 deletion xls/scheduling/run_pipeline_schedule.cc
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Expand Up @@ -232,7 +232,10 @@ absl::StatusOr<int64_t> FindMinimumWorstCaseThroughput(
// Extract the worst-case throughput from this schedule as an upper bound.
int64_t pessimistic_worst_case_throughput = 1;
for (Next* next : proc->next_values()) {
Node* state_read = next->state_read();
Node* state_read =
next->has_state_read()
? next->state_read()
: proc->GetStateReadByStateElement(next->state_element());
const int64_t backedge_length =
schedule_cycle_map[next] - schedule_cycle_map[state_read];
pessimistic_worst_case_throughput =
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