| Issue |
133579
|
| Summary |
[AVR] `-mrelax` does not work for a simple LED blink program
|
| Labels |
backend:AVR
|
| Assignees |
benshi001
|
| Reporter |
benshi001
|
the following a.cc
```
// clang --target=avr -gdwarf-4 --sysroot /data/home/bennshi/.arduino15/packages/arduino/tools/avr-gcc/ a.c -mrelax -Os -Wall -mmcu=atmega328
volatile unsigned int bas[200] = {0x20, 0x00, 60000};
void delay(unsigned int a) {
for (volatile int i = 0; i < a; i++) {}
}
int main() {
volatile char *p0 = (char *) 0x24;
volatile char *p1 = (char *) 0x25;
*p0 = 0x20;
for (;;) {
delay(bas[2]);
*p1 = bas[0];
delay(bas[2]);
*p1 = bas[1];
}
return 0;
}
```
if it is built with `-mrelax`, we can not see the LED blinking, with `-mno-relax` it works.
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