'too simple' benchmark

[gptsarthak]

Here is the "too simple" benchmark from benchmarksgame :
https://benchmarksgame-team.pages.debian.net/benchmarksgame/performance/toosimple.html
In Python:

from lpython import i32, f64

def main():
    n : i32 = 100000000
    sum : f64 = 0.0
    flip : f64 = -1.0
    i : i32 = 0
    for i in range(1,n):    
        flip *= -1.0        
        sum += flip / (2*i - 1)                                      
    print((sum*4.0))
main() 

In C :

#include <stdio.h>
#include <stdlib.h>

int main()
{
    long n = 100000000;
    double sum = 0.0;
    double flip = -1.0;
    for (long i = 1; i <= n; i++) {    
        flip *= -1.0;        
        sum += flip / (2*i - 1);               
    }                        
    printf("%.9f\n", sum*4.0);
    return 0;      
}

Results on PopOS 22.04 on AMD 5800u CPU

% gcc -O3 -march=native  simple.c       
% time ./a.out
3.141592644
./a.out  0.18s user 0.00s system 99% cpu 0.179 total
% lpython simple.py            
3.14159266358932587e+00
% time ./simple.out
3.14159266358932587e+00
./simple.out  0.48s user 0.00s system 99% cpu 0.479 total
% lpython --fast simple.py
3.14159266358932587e+00
% time ./simple.out       
3.14159266358932587e+00
./simple.out  0.18s user 0.00s system 99% cpu 0.179 total
% time PYTHONPATH=.. python simple.py
3.141592663589326
PYTHONPATH=.. python simple.py  10.78s user 0.00s system 99% cpu 10.787 total

Compiler	Time	Relative
gcc	0.179	1.00
Lpython	0.479	2.67
Lpython --fast	0.179	1.00
Python	10.78	60.22

Versions:

$ gcc --version
gcc (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ lpython --version
LPython version: 0.12.0-185-g609279265
Platform: Linux
Default target: x86_64-unknown-linux-gnu
$ python --version
Python 3.10.8

Result: Lpython is 60x faster than Cpython 🚀 and has the same performance as gcc

[certik]

Thanks @gptsarthak for testing it! Yes, LPython must have the same or better performance than C or C++, otherwise it's a bug that we need to fix.