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copybara-service merged 2 commits into from
Feb 4, 2026
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Merged

Properly handle const if expression when using proc-scoped channels #3745

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50bcf91
const if: fix unnecessary IR code with proc scoped channels
magancarz Feb 3, 2026
0a4d965
ir conversion: fix using incorrect type infos for parametric procs
magancarz Feb 3, 2026
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71 changes: 57 additions & 14 deletions xls/dslx/ir_convert/get_conversion_records.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -75,6 +75,29 @@ class ConversionRecordVisitor : public AstNodeVisitorWithDefault {
records_(records),
processed_invocations_(processed_invocations) {}

absl::Status VisitProcFunctionsWithSeparateTypeInfos(
Module* owner, const Function* config_function,
TypeInfo* config_type_info, const Function* next_function,
TypeInfo* next_type_info) {
// Get conversion records from invocations in this proc's "config"
// "next" functions and add to our list of records. Don't use Accept
// because that will run HandleFunction, which ignores "config" and
// "next" functions.
ConversionRecordVisitor config_visitor(
owner, config_type_info,
include_tests_, proc_id_factory_, top_,
resolved_proc_alias_, records_,
processed_invocations_);
XLS_RETURN_IF_ERROR(config_visitor.DefaultHandler(config_function));

ConversionRecordVisitor next_visitor(
owner, next_type_info,
include_tests_, proc_id_factory_, top_,
resolved_proc_alias_, records_,
processed_invocations_);
return next_visitor.DefaultHandler(next_function);
}

absl::StatusOr<ConversionRecord> SpawnDataToConversionRecord(
const SpawnData& spawn, ProcId proc_id) {
VLOG(5) << "Making conversion record for SpawnData with proc: "
Expand All @@ -83,14 +106,10 @@ class ConversionRecordVisitor : public AstNodeVisitorWithDefault {
<< "; config TI: " << std::hex << spawn.config_type_info
<< "; next TI: " << spawn.next_type_info;

ConversionRecordVisitor visitor(spawn.proc->owner(), spawn.next_type_info,
include_tests_, proc_id_factory_, top_,
resolved_proc_alias_, records_,
processed_invocations_);
// Get additional conversion records from invocations in this proc's "next"
// function and add to our list of records. Don't use Accept because that
// will run HandleFunction, which ignores "next" functions.
XLS_RETURN_IF_ERROR(visitor.DefaultHandler(&spawn.proc->next()));
XLS_RETURN_IF_ERROR(VisitProcFunctionsWithSeparateTypeInfos(
spawn.proc->owner(), &spawn.proc->config(),
spawn.config_type_info, &spawn.proc->next(),
spawn.next_type_info));

XLS_ASSIGN_OR_RETURN(
ConversionRecord config_record,
Expand All @@ -114,6 +133,21 @@ class ConversionRecordVisitor : public AstNodeVisitorWithDefault {
: *type_info_->GetImportedTypeInfo(node->owner());
}

absl::Status HandleConditional(const Conditional* expr) override {
if (expr->IsConst()) {
XLS_ASSIGN_OR_RETURN(InterpValue test_value,
GetTypeInfo(expr)->GetConstExpr(expr->test()));
if (test_value.IsTrue()) {
XLS_RETURN_IF_ERROR(DefaultHandler(expr->consequent()));
} else {
XLS_RETURN_IF_ERROR(DefaultHandler(ToExprNode(expr->alternate())));
}
return absl::OkStatus();
}

return DefaultHandler(expr);
}

// Generates a conversion record for the given function if it is a real
// function (not parametric or compiler-derived) that has no incoming calls
// known to `type_info_`. Also traverses such functions to ensure that
Expand Down Expand Up @@ -270,17 +304,26 @@ class ConversionRecordVisitor : public AstNodeVisitorWithDefault {
absl::Status HandleProc(const Proc* p) override {
VLOG(5) << "HandleProc " << p->ToString();
const Function* next_fn = &p->next();
// Handle any calls inside function bodies.
XLS_RETURN_IF_ERROR(DefaultHandler(next_fn));
// This is required in order to process cross-module spawns; otherwise it
// will never add procs from imported modules to the list of functions to
// convert.
XLS_RETURN_IF_ERROR(DefaultHandler(&p->config()));
// Traversing parametric procs is done later with proper
// type infos for proc's "config" and "next" functions separately.
if (!p->IsParametric()) {
// Handle any calls inside function bodies.
XLS_RETURN_IF_ERROR(DefaultHandler(next_fn));
// This is required in order to process cross-module spawns; otherwise it
// will never add procs from imported modules to the list of functions to
// convert.
XLS_RETURN_IF_ERROR(DefaultHandler(&p->config()));
}

ProcId proc_id = proc_id_factory_.CreateProcId(
/*parent=*/std::nullopt, const_cast<Proc*>(p),
/*count_as_new_instance=*/false);
if (top_ == next_fn && resolved_proc_alias_.has_value()) {
XLS_RETURN_IF_ERROR(VisitProcFunctionsWithSeparateTypeInfos(
top_->owner(), &p->config(),
resolved_proc_alias_->config_type_info, &p->next(),
resolved_proc_alias_->next_type_info));

proc_id.alias_name = resolved_proc_alias_->name;
XLS_ASSIGN_OR_RETURN(
ConversionRecord config_record,
Expand Down
115 changes: 115 additions & 0 deletions xls/dslx/ir_convert/ir_converter_test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -927,6 +927,121 @@ fn main() -> u32 {
ExpectIr(converted);
}

TEST_F(IrConverterTest, ConstConditionalProcScoped) {
constexpr std::string_view program = R"(
proc Multiply {
input: chan<u32> in;
output: chan<u32> out;

init {}

config(input: chan<u32> in, output: chan<u32> out) {
(input, output)
}

next(state: ()) {
let (tok, req) = recv(join(), input);
let data = req * u32:2;
let tok = send(tok, output, data);
}
}

proc Passthrough {
input: chan<u32> in;
output: chan<u32> out;

init {}

config(input: chan<u32> in, output: chan<u32> out) {
(input, output)
}

next(state: ()) {
let (tok, req) = recv(join(), input);
let tok = send(tok, output, req);
}
}

const CONFIG = u32:31;

proc Top {
init {}

config(req_r: chan<u32> in, resp_s: chan<u32> out) {
const if CONFIG <= u32:27 {
spawn Passthrough(req_r, resp_s);
} else {
spawn Multiply(req_r, resp_s);
};
()
}

next(state: ()) { state }
}
)";

ConvertOptions options;
options.lower_to_proc_scoped_channels = true;
XLS_ASSERT_OK_AND_ASSIGN(std::string converted,
ConvertOneFunctionForTest(program, "Top", options));
ExpectIr(converted);
}

TEST_F(IrConverterTest, ConstConditionalProcScopedWithParams) {
constexpr std::string_view program = R"(
proc Falsy {
req_r: chan<()> in;
resp_s: chan<bool> out;

config(req_r: chan<()> in, resp_s: chan<bool> out) { (req_r, resp_s) }

init { }

next(_: ()) {
let (tok, _d) = recv(join(), req_r);
let tok = send(tok, resp_s, false);
}
}

proc Truthy {
req_r: chan<()> in;
resp_s: chan<bool> out;

config(req_r: chan<()> in, resp_s: chan<bool> out) { (req_r, resp_s) }

init { }

next(_: ()) {
let (tok, _d) = recv(join(), req_r);
let tok = send(tok, resp_s, true);
}
}

proc Foo<CONFIG: bool> {
config(req_r: chan<()> in, resp_s: chan<bool> out) {
const if CONFIG {
spawn Truthy(req_r, resp_s);
} else {
spawn Falsy(req_r, resp_s);
};
()
}

init { }

next(_: ()) { }
}

pub proc Top = Foo<true>;
)";

ConvertOptions options;
options.lower_to_proc_scoped_channels = true;
XLS_ASSERT_OK_AND_ASSIGN(std::string converted,
ConvertOneFunctionForTest(program, "Top", options));
ExpectIr(converted);
}

TEST_F(IrConverterTest, ConstantsWithConditionalsPlusStuff) {
constexpr std::string_view program =
R"(
Expand Down
34 changes: 34 additions & 0 deletions xls/dslx/ir_convert/testdata/ir_converter_test_ConstConditionalProcScoped.ir
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Original file line number Diff line number Diff line change
@@ -0,0 +1,34 @@
package test_module

file_number 0 "test_module.x"

proc __test_module__Multiply_0_next<_input: bits[32] in, _output: bits[32] out>(__state: (), init={()}) {
chan_interface _input(direction=receive, kind=streaming, strictness=proven_mutually_exclusive, flow_control=ready_valid, flop_kind=none)
chan_interface _output(direction=send, kind=streaming, strictness=proven_mutually_exclusive, flow_control=ready_valid, flop_kind=none)
after_all.5: token = after_all(id=5)
literal.3: bits[1] = literal(value=1, id=3)
receive.6: (token, bits[32]) = receive(after_all.5, predicate=literal.3, channel=_input, id=6)
req: bits[32] = tuple_index(receive.6, index=1, id=9, pos=[(0,12,16)])
literal.10: bits[32] = literal(value=2, id=10, pos=[(0,13,23)])
tok: token = tuple_index(receive.6, index=0, id=8, pos=[(0,12,11)])
data: bits[32] = umul(req, literal.10, id=11, pos=[(0,13,17)])
__state: () = state_read(state_element=__state, id=2)
tuple.13: () = tuple(id=13, pos=[(0,11,19)])
__token: token = literal(value=token, id=1)
tuple.4: () = tuple(id=4, pos=[(0,8,6)])
tuple_index.7: token = tuple_index(receive.6, index=0, id=7)
tok__1: token = send(tok, data, predicate=literal.3, channel=_output, id=12)
next_value.14: () = next_value(param=__state, value=tuple.13, id=14)
}

top proc __test_module__Top_0_next<_req_r: bits[32] in, _resp_s: bits[32] out>(__state: (), init={()}) {
chan_interface _req_r(direction=receive, kind=streaming, strictness=proven_mutually_exclusive, flow_control=ready_valid, flop_kind=none)
chan_interface _resp_s(direction=send, kind=streaming, strictness=proven_mutually_exclusive, flow_control=ready_valid, flop_kind=none)
proc_instantiation __test_module__Multiply_0_next_inst(_req_r, _resp_s, proc=__test_module__Multiply_0_next)
__state: () = state_read(state_element=__state, id=16)
__token: token = literal(value=token, id=15)
literal.17: bits[1] = literal(value=1, id=17)
tuple.18: () = tuple(id=18, pos=[(0,42,13)])
tuple.19: () = tuple(id=19, pos=[(0,45,6)])
next_value.20: () = next_value(param=__state, value=__state, id=20)
}
35 changes: 35 additions & 0 deletions xls/dslx/ir_convert/testdata/ir_converter_test_ConstConditionalProcScopedWithParams.ir
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Original file line number Diff line number Diff line change
@@ -0,0 +1,35 @@
package test_module

file_number 0 "test_module.x"

proc __test_module__Truthy_0_next<_req_r: () in, _resp_s: bits[1] out>(__state: (), init={()}) {
chan_interface _req_r(direction=receive, kind=streaming, strictness=proven_mutually_exclusive, flow_control=ready_valid, flop_kind=none)
chan_interface _resp_s(direction=send, kind=streaming, strictness=proven_mutually_exclusive, flow_control=ready_valid, flop_kind=none)
after_all.5: token = after_all(id=5)
literal.3: bits[1] = literal(value=1, id=3)
receive.6: (token, ()) = receive(after_all.5, predicate=literal.3, channel=_req_r, id=6)
tok: token = tuple_index(receive.6, index=0, id=8, pos=[(0,24,13)])
literal.10: bits[1] = literal(value=1, id=10, pos=[(0,25,36)])
__state: () = state_read(state_element=__state, id=2)
tuple.12: () = tuple(id=12, pos=[(0,23,15)])
__token: token = literal(value=token, id=1)
tuple.4: () = tuple(id=4, pos=[(0,19,57)])
tuple_index.7: token = tuple_index(receive.6, index=0, id=7)
_d: () = tuple_index(receive.6, index=1, id=9, pos=[(0,24,18)])
tok__1: token = send(tok, literal.10, predicate=literal.3, channel=_resp_s, id=11)
next_value.13: () = next_value(param=__state, value=tuple.12, id=13)
}

top proc __test_module__Top_next<_req_r: () in, _resp_s: bits[1] out>(__state: (), init={()}) {
chan_interface _req_r(direction=receive, kind=streaming, strictness=proven_mutually_exclusive, flow_control=ready_valid, flop_kind=none)
chan_interface _resp_s(direction=send, kind=streaming, strictness=proven_mutually_exclusive, flow_control=ready_valid, flop_kind=none)
proc_instantiation __test_module__Truthy_0_next_inst(_req_r, _resp_s, proc=__test_module__Truthy_0_next)
__state: () = state_read(state_element=__state, id=15)
tuple.20: () = tuple(id=20, pos=[(0,41,17)])
__token: token = literal(value=token, id=14)
literal.16: bits[1] = literal(value=1, id=16)
CONFIG: bits[1] = literal(value=1, id=17, pos=[(0,29,11)])
tuple.18: () = tuple(id=18, pos=[(0,31,26)])
tuple.19: () = tuple(id=19, pos=[(0,36,10)])
next_value.21: () = next_value(param=__state, value=tuple.20, id=21)
}