From 3ed2041cbaddd4c29a019b5476471a114b5192d2 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 24 Apr 2026 15:36:26 +0000
Subject: [PATCH] drt: add -disable_auto_taper_ndr_nets flag to detailed_route

Exposes AUTO_TAPER_NDR_NETS as a user-controllable option in the
detailed_route Tcl command via a new -disable_auto_taper_ndr_nets flag.

Fixes The-OpenROAD-Project/OpenROAD#9995

Signed-off-by: GitHub Copilot <copilot@github.com>

Agent-Logs-Url: https://github.com/hpretl/OpenROAD/sessions/bfe7f851-ca02-4d23-ae14-e570fbc76522

Co-authored-by: hpretl <57392031+hpretl@users.noreply.github.com>
---
 src/drt/README.md                 | 2 ++
 src/drt/include/drt/TritonRoute.h | 1 +
 src/drt/src/TritonRoute.cpp       | 1 +
 src/drt/src/TritonRoute.i         | 6 ++++--
 src/drt/src/TritonRoute.tcl       | 6 ++++--
 5 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/drt/README.md b/src/drt/README.md
index 2fdeef94f6c..0d717b10abc 100644
--- a/src/drt/README.md
+++ b/src/drt/README.md
@@ -64,6 +64,7 @@ detailed_route
     [-save_guide_updates]
     [-repair_pdn_vias layer]
     [-single_step_dr]
+    [-disable_auto_taper_ndr_nets]
 ```
 
 #### Options
@@ -95,6 +96,7 @@ detailed_route
 | `-no_pin_access` | Disables pin access for routing. |
 | `-save_guide_updates` | Flag to save guides updates. |
 | `-repair_pdn_vias` | This option is used for PDKs where M1 and M2 power rails run in parallel. |
+| `-disable_auto_taper_ndr_nets` | Disables automatic tapering of NDR nets at pin connections. By default, tapering is enabled. |
 
 #### Developer arguments
 
diff --git a/src/drt/include/drt/TritonRoute.h b/src/drt/include/drt/TritonRoute.h
index 574ffe08346..3327dd1d9c7 100644
--- a/src/drt/include/drt/TritonRoute.h
+++ b/src/drt/include/drt/TritonRoute.h
@@ -78,6 +78,7 @@ struct ParamStruct
   bool saveGuideUpdates = false;
   std::string repairPDNLayerName;
   int num_threads = 1;
+  bool autoTaperNdrNets = true;
 };
 
 class TritonRoute : public PinAccessService
diff --git a/src/drt/src/TritonRoute.cpp b/src/drt/src/TritonRoute.cpp
index 84312a3ddc8..bdb4ba3cfb6 100644
--- a/src/drt/src/TritonRoute.cpp
+++ b/src/drt/src/TritonRoute.cpp
@@ -1324,6 +1324,7 @@ void TritonRoute::setParams(const ParamStruct& params)
   router_cfg_->SAVE_GUIDE_UPDATES = params.saveGuideUpdates;
   router_cfg_->REPAIR_PDN_LAYER_NAME = params.repairPDNLayerName;
   router_cfg_->MAX_THREADS = params.num_threads;
+  router_cfg_->AUTO_TAPER_NDR_NETS = params.autoTaperNdrNets;
 }
 
 void TritonRoute::addWorkerResults(
diff --git a/src/drt/src/TritonRoute.i b/src/drt/src/TritonRoute.i
index 5833c25cb6c..1fc56805a7b 100644
--- a/src/drt/src/TritonRoute.i
+++ b/src/drt/src/TritonRoute.i
@@ -66,7 +66,8 @@ void detailed_route_cmd(const char* outputMazeFile,
                         int minAccessPoints,
                         bool saveGuideUpdates,
                         const char* repairPDNLayerName,
-                        int drcReportIterStep)
+                        int drcReportIterStep,
+                        bool autoTaperNdrNets)
 {
   auto* router = ord::OpenRoad::openRoad()->getTritonRoute();
   const int num_threads = ord::OpenRoad::openRoad()->getThreadCount();
@@ -89,7 +90,8 @@ void detailed_route_cmd(const char* outputMazeFile,
                     minAccessPoints,
                     saveGuideUpdates,
                     repairPDNLayerName,
-                    num_threads});
+                    num_threads,
+                    autoTaperNdrNets});
   router->main();
   router->setDistributed(false);
 }
diff --git a/src/drt/src/TritonRoute.tcl b/src/drt/src/TritonRoute.tcl
index 75c0777e70f..41b2e886d57 100644
--- a/src/drt/src/TritonRoute.tcl
+++ b/src/drt/src/TritonRoute.tcl
@@ -28,6 +28,7 @@ sta::define_cmd_args "detailed_route" {
     [-save_guide_updates]
     [-repair_pdn_vias layer]
     [-single_step_dr]
+    [-disable_auto_taper_ndr_nets]
 }
 
 proc detailed_route { args } {
@@ -38,7 +39,7 @@ proc detailed_route { args } {
       -top_routing_layer -verbose -remote_host -remote_port -shared_volume \
       -cloud_size -min_access_points -repair_pdn_vias -drc_report_iter_step} \
     flags {-disable_via_gen -distributed -clean_patches -no_pin_access \
-           -single_step_dr -save_guide_updates}
+           -single_step_dr -save_guide_updates -disable_auto_taper_ndr_nets}
   sta::check_argc_eq0 "detailed_route" $args
 
   set enable_via_gen [expr ![info exists flags(-disable_via_gen)]]
@@ -48,6 +49,7 @@ proc detailed_route { args } {
   # development.  It is not listed in the help string intentionally.
   set single_step_dr [expr [info exists flags(-single_step_dr)]]
   set save_guide_updates [expr [info exists flags(-save_guide_updates)]]
+  set auto_taper_ndr_nets [expr ![info exists flags(-disable_auto_taper_ndr_nets)]]
 
   if { [info exists keys(-repair_pdn_vias)] } {
     set repair_pdn_vias $keys(-repair_pdn_vias)
@@ -166,7 +168,7 @@ proc detailed_route { args } {
     $via_in_pin_bottom_layer $via_in_pin_top_layer \
     $via_access_layer $or_seed $or_k $verbose \
     $clean_patches $no_pin_access $single_step_dr $min_access_points \
-    $save_guide_updates $repair_pdn_vias $drc_report_iter_step
+    $save_guide_updates $repair_pdn_vias $drc_report_iter_step $auto_taper_ndr_nets
 }
 
 proc detailed_route_num_drvs { args } {