Swift versus C++ g++ fastest performance

How the programs are written matters! Always look at the source code.

If the fastest programs are hand-written vector instructions, does the host language matter? You might be more interested in the less optimised programs — more seconds, less gz source code.

fannkuch-redux
source	secs	mem	gz	cpu secs
* C++ g++ #6	3.31	19,760	1535	13.11
* C++ g++ #7	14.03	19,760	1156	14.03
C++ g++ #5	7.85	19,760	987	30.68
* Swift #3	8.32	19,440	1103	32.99
C++ g++ #4	8.92	19,760	1445	35.00
Swift #8	35.13	19,444	470	35.12
C++ g++ #2	9.13	19,760	1446	35.73
C++ g++ #3	37.88	19,760	600	37.87
C++ g++	10.49	19,760	1065	41.21
n-body
source	secs	mem	gz	cpu secs
* C++ g++ #0	2.15	19,760	1933	2.15
* C++ g++ #7	4.11	19,760	1815	4.11
C++ g++ #9	5.14	19,760	1536	5.14
C++ g++ #3	5.32	19,760	1402	5.32
* Swift #3	5.43	19,440	1688	5.43
* C++ g++ #4	5.45	19,760	1434	5.45
* Swift #4	5.46	19,440	1361	5.46
* Swift #5	5.49	19,440	1372	5.49
* Swift #7	5.50	19,440	1333	5.50
Swift #6	5.78	19,440	1213	5.78
* C++ g++ #2	6.02	19,352	1524	6.01
C++ g++ #5	6.32	19,760	1544	6.32
C++ g++	6.61	19,760	1666	6.61
Swift #8	6.65	19,440	1285	6.65
C++ g++ #6	6.93	19,760	1674	6.93
Swift	7.85	19,440	1210	7.85
Swift #9	288.23	19,440	1532	288.20
spectral-norm
source	secs	mem	gz	cpu secs
* C++ g++ #6	0.73	19,760	1050	2.86
* C++ g++ #5	1.33	19,760	1050	5.28
Swift #8	5.33	19,568	411	5.33
C++ g++	5.33	19,760	459	5.33
Swift #3	1.43	19,440	607	5.69
C++ g++ #7	1.52	19,512	1284	6.04
mandelbrot
source	secs	mem	gz	cpu secs
* C++ g++ #4	0.89	35,344	3554	3.45
* C++ g++	0.89	34,952	1797	3.47
* C++ g++ #6	0.98	35,080	1014	3.87
* Swift #7	1.38	49,024	1147	5.49
* Swift #6	1.46	51,840	1147	5.78
C++ g++ #0	2.35	35,476	2752	9.30
* C++ g++ #7	4.86	35,176	749	13.28
C++ g++ #5	13.44	34,636	596	13.43
C++ g++ #9	3.52	35,120	732	13.55
C++ g++ #2	16.95	34,636	700	16.94
Swift #8	25.59	19,492	426	25.59
Swift	26.45	19,440	400	26.45
Swift #5	7.25	43,648	665	27.03
C++ g++ #3	27.37	19,760	421	27.36
* Swift #3		Bad Output
fasta
source	secs	mem	gz	cpu secs
C++ g++ #9	0.78	19,352	2758	1.54
C++ g++ #2	1.84	19,760	1129	1.84
C++ g++	1.92	19,760	1064	1.92
C++ g++ #3	2.63	19,760	1311	2.63
C++ g++ #7	0.87	19,760	2711	3.05
C++ g++ #4	3.32	19,760	1291	3.32
C++ g++ #5	1.06	19,760	2345	3.66
* Swift #2	2.11	19,440	1952	3.76
C++ g++ #6	1.07	19,760	2326	4.01
* Swift	5.15	19,440	1533	5.14
* Swift #3	2.18	31,248	2097	5.40
Swift #8	106.65	19,440	833	106.65
k-nucleotide
source	secs	mem	gz	cpu secs
C++ g++ #2	2.01	156,592	1634	5.98
C++ g++ #3	4.19	165,580	1280	13.94
C++ g++	6.96	757,156	1452	14.75
* Swift #2	14.54	260,820	1373	55.20
Swift #8	181.50	627,328	658	180.87
Swift #7	233.16	627,092	607	232.52
Swift		Make Error
reverse-complement
source	secs	mem	gz	cpu secs
* C++ g++ #2	0.74	499,916	2099	0.74
* Swift	1.95	798,228	1293	2.39
C++ g++ #6	3.30	1,517,824	1827	4.38
C++ g++	6.52	980,156	599	6.51
C++ g++ #5	37.59	771,632	704	37.58
C++ g++ #3		Bad Output
binary-trees
source	secs	mem	gz	cpu secs
C++ g++ #7	0.97	201,512	896	3.40
C++ g++ #5	1.16	200,724	891	4.10
C++ g++ #9	1.74	136,120	815	4.63
C++ g++ #3	1.91	265,636	951	4.74
C++ g++ #6	1.91	266,120	851	4.77
C++ g++ #4	2.22	266,136	826	5.20
C++ g++	2.65	2,153,044	760	9.23
C++ g++ #2	22.83	265,840	514	22.82
Swift	18.28	737,152	720	54.20
Swift #8	54.90	402,048	567	54.89
Swift #4	17.49	707,456	772	55.84
Swift #5	18.89	738,048	813	56.25
Swift #2	18.29	707,456	822	58.16
Swift #3	18.18	707,584	868	58.24
* Swift #9		Make Error
pidigits
source	secs	mem	gz	cpu secs
C++ g++ #4	0.71	19,760	521	0.71
* C++ g++ #5	0.73	19,760	804	0.73
* Swift #2	0.75	19,440	606	0.75
regex-redux
source	secs	mem	gz	cpu secs
C++ g++ #6	1.15	276,336	2856	2.24
C++ g++ #3	12.38	215,640	859	17.95
Swift #2	38.80	686,136	678	38.80
Swift	23.40	891,792	721	39.65
Swift #4	18.30	1,064,768	751	41.36
C++ g++		Make Error
C++ g++ #2		Make Error
C++ g++ #5		Make Error
C++ g++ #4		Make Error
Swift	Swift version 6.0 (swift-6.0-RELEASE) Target: x86_64-unknown-linux-gnu
C++ g++	g++ (Ubuntu 14.2.0-4ubuntu2) 14.2.0