avr-gcc: Optimierung von Addition uint8_t + int8_t

volatile signed char s;

volatile unsigned char i;

int main() {

  s += i;

}

volatile signed char s;

volatile unsigned char i;

int main() {

  s += i;

  7c:  80 91 60 00   lds  r24, 0x0060  ; 0x800060 <_edata>

  80:  20 91 61 00   lds  r18, 0x0061  ; 0x800061 <s>

  84:  90 e0         ldi  r25, 0x00  ; 0

  86:  82 0f         add  r24, r18

  88:  91 1d         adc  r25, r1

  8a:  27 fd         sbrc  r18, 7

  8c:  9a 95         dec  r25

  8e:  80 93 61 00   sts  0x0061, r24  ; 0x800061 <s>

  for (;;) {

  }

volatile signed char s;

volatile unsigned char i;

int main() {

  s += i;

  7c:  80 91 60 00   lds  r24, 0x0060  ; 0x800060 <_edata>

  80:  90 91 61 00   lds  r25, 0x0061  ; 0x800061 <s>

  84:  89 0f         add  r24, r25

  86:  80 93 61 00   sts  0x0061, r24  ; 0x800061 <s>

}