diff --git a/search/Latches.cc b/search/Latches.cc index 3c113c51..9dcd688a 100644 --- a/search/Latches.cc +++ b/search/Latches.cc @@ -323,6 +323,10 @@ Latches::latchOutArrival(const Path *data_path, ArcDelay &arc_delay, Arrival &q_arrival) { + q_tag = nullptr; + arc_delay = 0.0; + q_arrival = 0.0; + Scene *scene = data_path->scene(this); Sdc *sdc = scene->sdc(); const Mode *mode = scene->mode(); @@ -337,83 +341,110 @@ Latches::latchOutArrival(const Path *data_path, // Latch enable may be missing if library is malformed. switch (state) { case LatchEnableState::closed: - // Latch is disabled by constant enable. + // Latch is always closed because enable is constant. break; case LatchEnableState::open: { + // Latch is always open because enable is constant. ExceptionPath *excpt = exceptionTo(data_path, nullptr); if (!(excpt && excpt->isFalse())) { arc_delay = search_->deratedDelay(data_vertex, d_q_arc, d_q_edge, false, min_max, dcalc_ap, sdc); q_arrival = data_path->arrival() + arc_delay; - q_tag = data_path->tag(this); + // Copy the data tag but remove the drprClkPath. + // Levelization does not traverse latch D->Q edges, so in some cases + // level(Q) < level(D) + // Note that + // level(crprClkPath(data)) < level(D) + // The danger is that + // level(crprClkPath(data)) == level(Q) + // or some other downstream vertex. + // This can lead to data races when finding arrivals at the same level + // use multiple threads. + // Kill the crprClklPath to be safe. + const ClkInfo *data_clk_info = data_path->clkInfo(this); + const ClkInfo *q_clk_info = + search_->findClkInfo(scene, + data_clk_info->clkEdge(), + data_clk_info->clkSrc(), + data_clk_info->isPropagated(), + data_clk_info->genClkSrc(), + data_clk_info->isGenClkSrcPath(), + data_clk_info->pulseClkSense(), + data_clk_info->insertion(), + data_clk_info->latency(), + data_clk_info->uncertainties(), + min_max, nullptr); + q_tag = search_->findTag(scene, d_q_arc->toEdge()->asRiseFall(), + min_max, q_clk_info, false, + nullptr, false, data_path->tag(this)->states(), + false, nullptr); } - } break; + } case LatchEnableState::enabled: { const MinMax *tgt_min_max = data_path->tgtClkMinMax(this); VertexPathIterator enable_iter(enable_vertex, scene, tgt_min_max, enable_rf, this); while (enable_iter.hasNext()) { Path *enable_path = enable_iter.next(); - const ClkInfo *en_clk_info = enable_path->clkInfo(this); - const ClockEdge *en_clk_edge = en_clk_info->clkEdge(); - if (enable_path->isClock(this)) { - ExceptionPath *excpt = exceptionTo(data_path, en_clk_edge); - // D->Q is disabled when if there is a path delay -to D or EN clk. - if (!(excpt && (excpt->isFalse() - || excpt->isPathDelay()))) { - Path *disable_path = latchEnableOtherPath(enable_path); - Delay borrow, time_given_to_startpoint; - Arrival adjusted_data_arrival; - Required required; - latchRequired(data_path, enable_path, disable_path, - required, borrow, adjusted_data_arrival, - time_given_to_startpoint); - if (delayGreater(borrow, 0.0, this)) { - // Latch is transparent when data arrives. - arc_delay = search_->deratedDelay(data_vertex, d_q_arc, d_q_edge, - false, min_max, dcalc_ap, sdc); - q_arrival = adjusted_data_arrival + arc_delay; - // Tag switcheroo - data passing thru gets latch enable tag. - // States and path ap come from Q, everything else from enable. - Path *crpr_clk_path = crprActive(mode) ? enable_path : nullptr; - const ClkInfo *q_clk_info = - search_->findClkInfo(en_clk_info->scene(), - en_clk_edge, - en_clk_info->clkSrc(), - en_clk_info->isPropagated(), - en_clk_info->genClkSrc(), - en_clk_info->isGenClkSrcPath(), - en_clk_info->pulseClkSense(), - en_clk_info->insertion(), - en_clk_info->latency(), - en_clk_info->uncertainties(), - min_max, crpr_clk_path); - const RiseFall *q_rf = d_q_arc->toEdge()->asRiseFall(); - ExceptionStateSet *states = nullptr; - // Latch data pin is a valid exception -from pin. - if (sdc->exceptionFromStates(data_path->pin(this), - data_path->transition(this), - nullptr, nullptr, // clk below - MinMax::max(), states) - // -from enable non-filter exceptions apply. - && sdc->exceptionFromStates(enable_vertex->pin(), - enable_rf, - en_clk_edge->clock(), - en_clk_edge->transition(), - MinMax::max(), false, states)) - q_tag = search_->findTag(enable_path->tag(this)->scene(), - q_rf, MinMax::max(), q_clk_info, false, - nullptr, false, states, true, nullptr); - } - return; - } - } + const ClkInfo *en_clk_info = enable_path->clkInfo(this); + const ClockEdge *en_clk_edge = en_clk_info->clkEdge(); + if (enable_path->isClock(this)) { + ExceptionPath *excpt = exceptionTo(data_path, en_clk_edge); + // D->Q is disabled when if there is a path delay -to D or EN clk. + if (!(excpt && (excpt->isFalse() + || excpt->isPathDelay()))) { + Path *disable_path = latchEnableOtherPath(enable_path); + Delay borrow, time_given_to_startpoint; + Arrival adjusted_data_arrival; + Required required; + latchRequired(data_path, enable_path, disable_path, + required, borrow, adjusted_data_arrival, + time_given_to_startpoint); + if (delayGreater(borrow, 0.0, this)) { + // Latch is transparent when data arrives. + arc_delay = search_->deratedDelay(data_vertex, d_q_arc, d_q_edge, + false, min_max, dcalc_ap, sdc); + q_arrival = adjusted_data_arrival + arc_delay; + // Tag switcheroo - data passing thru gets latch enable tag. + // States and path ap come from Q, everything else from enable. + Path *crpr_clk_path = crprActive(mode) ? enable_path : nullptr; + const ClkInfo *q_clk_info = + search_->findClkInfo(scene, + en_clk_edge, + en_clk_info->clkSrc(), + en_clk_info->isPropagated(), + en_clk_info->genClkSrc(), + en_clk_info->isGenClkSrcPath(), + en_clk_info->pulseClkSense(), + en_clk_info->insertion(), + en_clk_info->latency(), + en_clk_info->uncertainties(), + min_max, crpr_clk_path); + ExceptionStateSet *states = nullptr; + // Latch data pin is a valid exception -from pin. + if (sdc->exceptionFromStates(data_path->pin(this), + data_path->transition(this), + nullptr, nullptr, // clk below + MinMax::max(), states) + // -from enable non-filter exceptions apply. + && sdc->exceptionFromStates(enable_vertex->pin(), + enable_rf, + en_clk_edge->clock(), + en_clk_edge->transition(), + MinMax::max(), false, states)) + q_tag = search_->findTag(scene, d_q_arc->toEdge()->asRiseFall(), + MinMax::max(), q_clk_info, false, + nullptr, false, states, true, nullptr); + } + return; + } + } } // No enable path found. - } break; } + } } ExceptionPath * diff --git a/search/Search.cc b/search/Search.cc index 32956145..aca08dfb 100644 --- a/search/Search.cc +++ b/search/Search.cc @@ -3654,7 +3654,7 @@ RequiredVisitor::visitFromToPath(const Pin *, const MinMax *min_max) { // Don't propagate required times through latch D->Q edges. - if (edge->role() != TimingRole::latchDtoQ()) { + if (!edge->role()->isLatchDtoQ()) { debugPrint(debug_, "search", 3, " %s -> %s %s", from_rf->shortName(), to_rf->shortName(),