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feat: tune default delay synthesis strategy #241

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Merged
Emin017 merged 1 commit into from
Aug 25, 2026
Merged

feat: tune default delay synthesis strategy #241

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8 changes: 4 additions & 4 deletions chipcompiler/tools/yosys/scripts/yosys_synthesis.tcl
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Original file line number Diff line number Diff line change
Expand Up @@ -42,7 +42,7 @@ yosys -import
# DELAY N — maximize frequency
# AREA N — minimize area
# BALANCE N — balanced PPA
set synth_strategy "BALANCE 3"
set synth_strategy "DELAY 4"
if {[info exists env(YOSYS_SYNTH_STRATEGY)]} {
# TODO: Move this to global_var.tcl
set synth_strategy $::env(YOSYS_SYNTH_STRATEGY)
Expand Down Expand Up @@ -70,11 +70,11 @@ set valid_types {DELAY AREA BALANCE}

# --- DELAY family ---
# Slack margin: tighten target to push frequency (<1 = tighter)
set delay_slack_margin 0.92
set delay_slack_margin 0.95
# Redelay depth
set delay_retime_M 8
# Max fanout for buffer insertion
set delay_max_FO 24
set delay_max_FO 20
# Multi-pass: 0=off, 1=on (second ABC pass to reinforce critical paths)
set delay_multipass 1
# Pass-2 relaxation factor
Expand Down Expand Up @@ -195,7 +195,7 @@ close $abc_constr_file

#=======================================================================
# DELAY scripts — maximize frequency
# 12 scripts (index 0..11)
# 14 scripts (index 0..13)
# Common prefix: fx;mfs;strash;refactor;resyn2;retime_dly;scleanup
# Mapper: abc_map_tight (map,-p,-B,0.2,-A,0.9,-M,0)
# Fine-tune: abc_finetune_delay / delay2 / delay3 (upsize+buffer)
Expand Down
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