ABC_AREA seemingly worsens synthesis results for sky130hd/gcd design

[CooperDeng]

Hi all,

I am following the tutorial(Sky130hd + GCD example) for getting to work with area optimization, and I have found the result coming from sky130hd/gcd to be somewhat weird, specifically, resources allocated with ABC_AREA enabled seems to be worse than when it is not, which is a bit counter-intuitive for me - what could the reason behind this be?

Furthermore, without ABC_AREA enabled, it seems that it will automatically run ABC_SPEED, I am confused about where this could be originating from, I have attached my config.mk and 1_1yosys_canonicalize.log for both ABC_AREA with and without.

1_1_yosys_canonicalize_with_abc.log
1_1_yosys_canonicalize_without_abc.log
synth_stat_with_abc.txt
synth_stat_without_abc.txt

config.mk with ABC_AREA = 1:

export DESIGN_NAME = gcd
export PLATFORM    = sky130hd

export VERILOG_FILES = $(DESIGN_HOME)/src/$(DESIGN_NICKNAME)/gcd.v
export SDC_FILE      = $(DESIGN_HOME)/$(PLATFORM)/$(DESIGN_NICKNAME)/constraint.sdc

export ABC_AREA = 1

# Adders degrade GCD
export ADDER_MAP_FILE :=

export CORE_UTILIZATION = 40
export TNS_END_PERCENT = 100
export EQUIVALENCE_CHECK   ?=   1
export REMOVE_CELLS_FOR_EQY = sky130_fd_sc_hd__tapvpwrvgnd*`

config.mk without ABC_AREA = 1 (default):

export DESIGN_NAME = gcd
export PLATFORM    = sky130hd

export VERILOG_FILES = $(DESIGN_HOME)/src/$(DESIGN_NICKNAME)/gcd.v
export SDC_FILE      = $(DESIGN_HOME)/$(PLATFORM)/$(DESIGN_NICKNAME)/constraint.sdc

# Adders degrade GCD
export ADDER_MAP_FILE :=

export CORE_UTILIZATION = 40
export TNS_END_PERCENT = 100
export EQUIVALENCE_CHECK   ?=   1
export REMOVE_CELLS_FOR_EQY = sky130_fd_sc_hd__tapvpwrvgnd*

Any help is much appreciated!