The-OpenROAD-Project · openroad-ci · Apr 22, 2026 · Apr 22, 2026 · Apr 23, 2026 · Apr 23, 2026
diff --git a/docs/user/FlowVariables.md b/docs/user/FlowVariables.md
@@ -140,6 +140,7 @@ configuration file.
 | <a name="DISABLE_VIA_GEN"></a>DISABLE_VIA_GEN| Passed as -disable_via_gen to detailed_route.| |
 | <a name="DONT_BUFFER_PORTS"></a>DONT_BUFFER_PORTS| Do not buffer input/output ports during floorplanning.| 0|
 | <a name="DONT_USE_CELLS"></a>DONT_USE_CELLS| Dont use cells eases pin access in detailed routing.| |
+| <a name="DPL_USE_OLD_DIAMOND"></a>DPL_USE_OLD_DIAMOND| Use the former diamond search legalizer for detailed placement instead of the default negotiation legalizer.| 0|
 | <a name="DPO_MAX_DISPLACEMENT"></a>DPO_MAX_DISPLACEMENT| Specifies how far an instance can be moved when optimizing.| 5 1|
 | <a name="EARLY_SIZING_CAP_RATIO"></a>EARLY_SIZING_CAP_RATIO| Ratio between the input pin capacitance and the output pin load during initial gate sizing.| |
 | <a name="ENABLE_DPO"></a>ENABLE_DPO| Enable detail placement with improve_placement feature.| 1|
@@ -321,7 +322,6 @@ configuration file.
 | <a name="TNS_END_PERCENT"></a>TNS_END_PERCENT| Default TNS_END_PERCENT value for post CTS timing repair. Try fixing all violating endpoints by default (reduce to 5% for runtime). Specifies how many percent of violating paths to fix [0-100]. Worst path will always be fixed.| 100|
 | <a name="UNSET_ABC9_BOX_CELLS"></a>UNSET_ABC9_BOX_CELLS| List of cells to unset the abc9_box attribute on| |
 | <a name="USE_FILL"></a>USE_FILL| Whether to perform metal density filling.| 0|
-| <a name="USE_NEGOTIATION"></a>USE_NEGOTIATION| Enable using negotiation legalizer for detailed placement.| 0|
 | <a name="VERILOG_DEFINES"></a>VERILOG_DEFINES| Preprocessor defines passed to the language frontend. Example: `-D HPDCACHE_ASSERT_OFF`| |
 | <a name="VERILOG_FILES"></a>VERILOG_FILES| The path to the design Verilog/SystemVerilog files providing a description of modules.| |
 | <a name="VERILOG_INCLUDE_DIRS"></a>VERILOG_INCLUDE_DIRS| Specifies the include directories for the Verilog input files.| |
@@ -462,6 +462,7 @@ configuration file.
 - [CLUSTER_FLOPS_ARGS](#CLUSTER_FLOPS_ARGS)
 - [DETAIL_PLACEMENT_ARGS](#DETAIL_PLACEMENT_ARGS)
 - [DONT_BUFFER_PORTS](#DONT_BUFFER_PORTS)
+- [DPL_USE_OLD_DIAMOND](#DPL_USE_OLD_DIAMOND)
 - [EARLY_SIZING_CAP_RATIO](#EARLY_SIZING_CAP_RATIO)
 - [FLOORPLAN_DEF](#FLOORPLAN_DEF)
 - [GLOBAL_PLACEMENT_ARGS](#GLOBAL_PLACEMENT_ARGS)
@@ -507,6 +508,7 @@ configuration file.
 - [CTS_SNAPSHOT](#CTS_SNAPSHOT)
 - [CTS_SNAPSHOTS](#CTS_SNAPSHOTS)
 - [DETAILED_METRICS](#DETAILED_METRICS)
+- [DPL_USE_OLD_DIAMOND](#DPL_USE_OLD_DIAMOND)
 - [HOLD_SLACK_MARGIN](#HOLD_SLACK_MARGIN)
 - [LEC_AUX_VERILOG_FILES](#LEC_AUX_VERILOG_FILES)
 - [LEC_CHECK](#LEC_CHECK)
@@ -531,6 +533,7 @@ configuration file.
 
 - [CELL_PAD_IN_SITES_DETAIL_PLACEMENT](#CELL_PAD_IN_SITES_DETAIL_PLACEMENT)
 - [DETAILED_METRICS](#DETAILED_METRICS)
+- [DPL_USE_OLD_DIAMOND](#DPL_USE_OLD_DIAMOND)
 - [ENABLE_RESISTANCE_AWARE](#ENABLE_RESISTANCE_AWARE)
 - [GLOBAL_ROUTE_ARGS](#GLOBAL_ROUTE_ARGS)
 - [HOLD_SLACK_MARGIN](#HOLD_SLACK_MARGIN)
@@ -660,5 +663,4 @@ configuration file.
 - [TAP_CELL_NAME](#TAP_CELL_NAME)
 - [TECH_LEF](#TECH_LEF)
 - [USE_FILL](#USE_FILL)
-- [USE_NEGOTIATION](#USE_NEGOTIATION)
 
diff --git a/flow/designs/nangate45/swerv/config.mk b/flow/designs/nangate45/swerv/config.mk
@@ -4,7 +4,7 @@ export PLATFORM    = nangate45
 export VERILOG_FILES = $(DESIGN_HOME)/src/$(DESIGN_NAME)/swerv_wrapper.sv2v.v
 export SDC_FILE      = $(DESIGN_HOME)/$(PLATFORM)/$(DESIGN_NAME)/constraint.sdc
 
-export CORE_UTILIZATION = 65
+export CORE_UTILIZATION = 64
 export CORE_ASPECT_RATIO = 1
 export CORE_MARGIN = 5
 

diff --git a/flow/designs/sky130hd/aes/config.mk b/flow/designs/sky130hd/aes/config.mk
@@ -7,7 +7,7 @@ export SDC_FILE      = $(DESIGN_HOME)/$(PLATFORM)/$(DESIGN_NICKNAME)/constraint.
 
 export PLACE_PINS_ARGS = -min_distance 4 -min_distance_in_tracks
 
-export CORE_UTILIZATION = 35
+export CORE_UTILIZATION = 34
 export CORE_ASPECT_RATIO = 1
 export CORE_MARGIN = 2
 

diff --git a/flow/designs/sky130hd/gcd/config.mk b/flow/designs/sky130hd/gcd/config.mk
@@ -7,7 +7,7 @@ export SDC_FILE      = $(DESIGN_HOME)/$(PLATFORM)/$(DESIGN_NICKNAME)/constraint.
 # Adders degrade GCD
 export ADDER_MAP_FILE :=
 
-export CORE_UTILIZATION = 40
+export CORE_UTILIZATION = 39
 export TNS_END_PERCENT = 100
 export SWAP_ARITH_OPERATORS = 1
 export OPENROAD_HIERARCHICAL = 1
diff --git a/flow/scripts/cts.tcl b/flow/scripts/cts.tcl
@@ -47,7 +47,7 @@ set_placement_padding -global \
   -right $::env(CELL_PAD_IN_SITES_DETAIL_PLACEMENT)
 
 set dpl_args {}
-append_env_var dpl_args USE_NEGOTIATION -use_negotiation 0
+append_env_var dpl_args DPL_USE_OLD_DIAMOND -use_old_diamond 0
 set result [catch { log_cmd detailed_placement {*}$dpl_args } msg]
 if { $result != 0 } {
   save_progress 4_1_error

diff --git a/flow/scripts/detail_place.tcl b/flow/scripts/detail_place.tcl
@@ -16,7 +16,7 @@ proc do_dpl { } {
     -left $::env(CELL_PAD_IN_SITES_DETAIL_PLACEMENT) \
     -right $::env(CELL_PAD_IN_SITES_DETAIL_PLACEMENT)
   set dpl_args [env_var_or_empty DETAIL_PLACEMENT_ARGS]
-  append_env_var dpl_args USE_NEGOTIATION -use_negotiation 0
+  append_env_var dpl_args DPL_USE_OLD_DIAMOND -use_old_diamond 0
   log_cmd detailed_placement {*}$dpl_args
 
   if { $::env(ENABLE_DPO) } {

diff --git a/flow/scripts/global_route.tcl b/flow/scripts/global_route.tcl
@@ -62,7 +62,7 @@ proc global_route_helper { } {
     # Running DPL to fix overlapped instances
     # Run to get modified net by DPL
     set dpl_args {}
-    append_env_var dpl_args USE_NEGOTIATION -use_negotiation 0
+    append_env_var dpl_args DPL_USE_OLD_DIAMOND -use_old_diamond 0
     log_cmd global_route -start_incremental
     log_cmd detailed_placement {*}$dpl_args
     # Route only the modified net by DPL

diff --git a/flow/scripts/variables.json b/flow/scripts/variables.json
diff --git a/flow/scripts/variables.yaml b/flow/scripts/variables.yaml
@@ -622,10 +622,14 @@ DPO_MAX_DISPLACEMENT:
   description: |
     Specifies how far an instance can be moved when optimizing.
   default: 5 1
-USE_NEGOTIATION:
+DPL_USE_OLD_DIAMOND:
   description: |
-    Enable using negotiation legalizer for detailed placement.
+    Use the former diamond search legalizer for detailed placement instead of the default negotiation legalizer.
   default: 0
+  stages:
+    - place
+    - cts
+    - grt
 GPL_TIMING_DRIVEN:
   description: |
     Specifies whether the placer should use timing driven placement.

diff --git a/tools/OpenROAD b/tools/OpenROAD