The EPFL Combinational Benchmark Suite

The EPFL Combinational Benchmark Suite was introduced in 2015 with the aim of defining a new comparative standard for the logic optimization and synthesis community. It originally consisted of 23 combinational circuits designed to challenge modern logic optimization tools. The benchmark suite is divided into arithmetic, random/control and MtM circuits, and each circuit is distributed in Verilog, VHDL, BLIF and AIGER formats.

Arithmetic Benchmarks
The EPFL benchmark suite has 10 arithmetic benchmarks. They are obtained by an automated mapping of arithmetic computational algorithms into basic logic gates. Examples are square-root, divisor, multipliers, adder, etc; they come in different bit-widths to provide diversity in the implementation complexity. The initial implementations are intendedly sub-optimal to test the ability of optimization tools. LUT-6 mapping experiments for the arithmetic EPFL combinational benchmarks are listed in the following Table. They are performed using ABC academic tool, with the mapping command if -K 6.

Benchmark name	Inputs	Outputs	LUT-6 count	Levels
Adder	256	129	254	51
Barrel shifter	135	128	512	4
Divisor	128	128	9311	867
Hypotenuse	256	128	44635	4194
Log2	32	32	8008	77
Max	512	130	842	56
Multiplier	128	128	5913	53
Sine	24	25	1458	42
Square-root	128	64	5720	1033
Square	64	128	3985	50
Total	1663	1020	80638	6427

Random/Control Benchmarks
The EPFL benchmark suite has 10 random/control benchmarks. They include various types of controllers, arbiters, routers, converters, decoders, voters and random functions, mapped into simple gates from their behavioral descriptions. Also here, the initial implementations are intendedly unoptimized. LUT-6 mapping experiments for the random/control EPFL combinational benchmarks are listed in the following Table. They are performed using ABC academic tool, with the mapping command if -K 6.

Benchmark name	Inputs	Outputs	LUT-6 count	Levels
Round-robin arbiter	256	129	2722	18
Alu control unit	7	26	29	2
Coding-cavlc	10	11	122	4
Decoder	8	256	287	2
i2c controller	147	142	365	4
int to float converter	11	7	49	3
Memory controller	1204	1231	12096	25
Priority encoder	128	8	210	31
Lookahead XY router	60	30	89	7
Voter	1001	1	2691	16
Total	2832	1841	18660	112

More than ten Miliong gates (MtM) Benchmarks
The EPFL benchmark suite has 3 MtM benchmarks. These benchmarks are designed to challenge the size capacity of modern optimization tools; they are extracted from a set of random Boolean functions, generated with a custom computer program, using as selection metric the implementation complexity. LUT-6 mapping experiments for the MtM EPFL combinational benchmarks are listed in the following Table. They are performed using ABC academic tool, with the mapping command if -K 6.

Benchmark name	Inputs	Outputs	LUT-6 count	Levels
sixteen	117	50	5648909	29
twenty	137	60	7189658	33
twentythree	153	68	8246898	36
Total	407	178	21085465	98

The MtM benchmarks can be downloaded at https://zenodo.org/record/2572934#.XGxRiS3MzuM

Best LUT-6 implementation

We keep track of the best optimization results, mapped into LUT-6, for size and depth metrics.

Submit your best LUT-6 implementation!

We encourage researchers to submit their best LUT-6 implementations in BLIF format for one or more of the benchmarks:

• at benchmarks@groupes.epfl.ch (in case the files exceed 3 MB please provide a download link in the email)
• or with a pull request to this repository.

Also the methodology used to optimize/map the circuits needs to be specified. We will run combinational equivalence checking and verify the claimed improvements over the current best implementation. If passing all tests, we will publish online the circuit together with the author’s name and affiliation as symbolic recognition.

The results presented above are NOT the best results, but they are the ORIGINAL benchmarks. All best known results can be found at the tags on this repository.

Submission deadline 2025

The latest best results for the 2024 competition have been published. Results for the 2025 competition will be collected a few weeks before IWLS 2025, with more details to be announced later.

References

The EPFL combinational benchmarks are explained in the paper The EPFL Combinational Benchmark Suite, presented at the International Workshop on Logic Synthesis 2015

Other benchmark sets

Multi-output PLA benchmarks are a set of 9 multiple-output PLA tables taken from an instruction decoder. These PLA files were used in the paper B. Schmitt, A. Mishchenko, V. Kravets, R. Brayton, and A. Reis, "Fast-extract with cube hashing", Proc. ASP-DAC'17 and can be downloaded at https://people.eecs.berkeley.edu/~alanmi/benchmarks/table_ex/