optimization process makes the top proc empty #2500

top proc __matmul_4x4__matmul_4x4_0_next() {
}

E0626 21:34:41.678815     277 block_stitching_pass.cc:487] INTERNAL: XLS_RET_CHECK failure (xls/codegen/block_stitching_pass.cc:487) channel->channel_config().fifo_config().has_value() Channel matmul_4x4__east_west__0_0 has no fifo config.
0x564b1b769fdd: xabsl::StatusBuilder::CreateStatusAndConditionallyLog()
0x564b19bdaee9: xabsl::StatusBuilder::operator absl::lts_20250127::Status()
0x564b19c6793f: xls::verilog::(anonymous namespace)::StitchStreamingChannel()
0x564b19c5bddd: xls::verilog::(anonymous namespace)::StitchBlocks()
0x564b19c594d2: xls::verilog::BlockStitchingPass::RunInternal()
0x564b19c40bbf: xls::PassBase<>::Run()
0x564b19c41b36: xls::CompoundPassBase<>::RunNested()
0x564b19c435ac: xls::CompoundPassBase<>::RunInternal()
0x564b19c40bbf: xls::PassBase<>::Run()
0x564b19c3703a: xls::verilog::ToPipelineModuleText()
0x564b19c292d6: xls::(anonymous namespace)::CodegenFromMetadata()
0x564b19c2a119: xls::ScheduleAndCodegen()
0x564b19bd87a0: xls::(anonymous namespace)::RealMain()
0x564b19bd82c7: main
0x7feca95881ca: [unknown]
0x7feca958828b: __libc_start_main
0x564b19bd81a5: _start

Error: INTERNAL: XLS_RET_CHECK failure (xls/codegen/block_stitching_pass.cc:487) channel->channel_config().fifo_config().has_value() Channel matmul_4x4__east_west__0_0 has no fifo config.; Running pass #0: Create container block that instantiates and stitches blocks together. [short: block_stitching]; Running pass #0: Top level codegen pass pipeline [short: codegen]