Atmega328P constantly restarting when defining a function

Question

I wanted to make a simple led on/off program using USART interface. When the code doesn't have any functions other than main it runs fine, however Arduino keeps resetting when one is included. At this point I have no clue what could I be doing wrong. Here's the code:

#include <avr/io.h>
#include <util/delay.h>
#define BAUD 19200
#define BAUDRATE ((F_CPU / 16 / BAUD) - 1)
// void init()
// {
// // Keeps resetting when uncommented, runs fine when commented
// }
int main() {
 // Initialize USART
 UBRR0H = (BAUDRATE >> 8);
 UBRR0L = BAUDRATE;
 UCSR0B = (1 << RXEN0);
 UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);
 // Set bit 3 to output and pull it high
 DDRD |= 0b00001000;
 PORTD = 0b00001000;
 char char_arr[128];
 while(1)
 {
 int i;
 // Read USART
 for(i = 0; i < 128; i++){
 loop_until_bit_is_set(UCSR0A, RXC0);
 char c = UDR0;
 if(c == '\r')
 break;
 char_arr[i] = c;
 }
 // Handle received characters
 for(int j = 0; j < i; j++){
 switch(char_arr[j]){
 case '1': 
 PORTD = 0b00001000; 
 break;
 case '0': 
 PORTD = 0b00000000; 
 break;
 }
 _delay_ms(100);
 }
 }
}

• Edgar Bonet: Does this happen if the function has a name other than init()?
• L1RG0: @EdgarBonet yes, function name doesn't matter
• jsotola: the compiler should remove that function during optimization, because the function is not used .... maybe the problem is in the compiler command line