From a5d2358a60084361902583f4fa024d2d53ce6c2c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marcin=20Ko=C5=9Bcielnicki?= Date: Tue, 14 Jan 2020 22:48:40 +0100 Subject: fsm_detect: Add a cache to avoid excessive CPU usage for big mux networks. Fixes #1634. --- passes/fsm/fsm_detect.cc | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) (limited to 'passes/fsm') diff --git a/passes/fsm/fsm_detect.cc b/passes/fsm/fsm_detect.cc index fb3896669..a1c8067b4 100644 --- a/passes/fsm/fsm_detect.cc +++ b/passes/fsm/fsm_detect.cc @@ -34,13 +34,20 @@ static SigSet sig2driver, sig2user; static std::set muxtree_cells; static SigPool sig_at_port; -static bool check_state_mux_tree(RTLIL::SigSpec old_sig, RTLIL::SigSpec sig, pool &recursion_monitor) +static bool check_state_mux_tree(RTLIL::SigSpec old_sig, RTLIL::SigSpec sig, pool &recursion_monitor, dict &mux_tree_cache) { + if (mux_tree_cache.find(sig) != mux_tree_cache.end()) + return mux_tree_cache.at(sig); + if (sig.is_fully_const() || old_sig == sig) { +ret_true: + mux_tree_cache[sig] = true; return true; } if (sig_at_port.check_any(assign_map(sig))) { +ret_false: + mux_tree_cache[sig] = false; return false; } @@ -49,13 +56,13 @@ static bool check_state_mux_tree(RTLIL::SigSpec old_sig, RTLIL::SigSpec sig, poo for (auto &cellport : cellport_list) { if ((cellport.first->type != "$mux" && cellport.first->type != "$pmux") || cellport.second != "\\Y") { - return false; + goto ret_false; } if (recursion_monitor.count(cellport.first)) { log_warning("logic loop in mux tree at signal %s in module %s.\n", log_signal(sig), RTLIL::id2cstr(module->name)); - return false; + goto ret_false; } recursion_monitor.insert(cellport.first); @@ -63,22 +70,22 @@ static bool check_state_mux_tree(RTLIL::SigSpec old_sig, RTLIL::SigSpec sig, poo RTLIL::SigSpec sig_a = assign_map(cellport.first->getPort("\\A")); RTLIL::SigSpec sig_b = assign_map(cellport.first->getPort("\\B")); - if (!check_state_mux_tree(old_sig, sig_a, recursion_monitor)) { + if (!check_state_mux_tree(old_sig, sig_a, recursion_monitor, mux_tree_cache)) { recursion_monitor.erase(cellport.first); - return false; + goto ret_false; } for (int i = 0; i < sig_b.size(); i += sig_a.size()) - if (!check_state_mux_tree(old_sig, sig_b.extract(i, sig_a.size()), recursion_monitor)) { + if (!check_state_mux_tree(old_sig, sig_b.extract(i, sig_a.size()), recursion_monitor, mux_tree_cache)) { recursion_monitor.erase(cellport.first); - return false; + goto ret_false; } recursion_monitor.erase(cellport.first); muxtree_cells.insert(cellport.first); } - return true; + goto ret_true; } static bool check_state_users(RTLIL::SigSpec sig) @@ -143,11 +150,12 @@ static void detect_fsm(RTLIL::Wire *wire) pool recursion_monitor; RTLIL::SigSpec sig_q = assign_map(cellport.first->getPort("\\Q")); RTLIL::SigSpec sig_d = assign_map(cellport.first->getPort("\\D")); + dict mux_tree_cache; if (sig_q != assign_map(wire)) continue; - looks_like_state_reg = check_state_mux_tree(sig_q, sig_d, recursion_monitor); + looks_like_state_reg = check_state_mux_tree(sig_q, sig_d, recursion_monitor, mux_tree_cache); looks_like_good_state_reg = check_state_users(sig_q); if (!looks_like_state_reg) -- cgit v1.2.3