[Bug middle-end/31528] Inlining with -Os increases code size

["abnikant dot singh at atmel dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #9 from abnikant dot singh at atmel dot com  2010-09-07 11:36 -------
gcc version 4.6.0 20100907 (experimental) is not performing the inline in -Os
for the test case:

#define UCSRA (*(volatile unsigned char *)0x2B)
#define UDRE 5
#define UDR   (*(volatile unsigned char *)0x2C)

static void putch(char ch);

void putch(char ch)
{
  while (!(UCSRA & (1<<UDRE)));
  UDR = ch;
}

int main(void)
{
  putch(0); 
  putch(1); 
  return 0;
}
The generated assembly with avr-gcc -S -Os test.c is:

putch:
/* prologue: function */
/* frame size = 0 */
/* stack size = 0 */
.L__stack_usage = 0
.L2:
        sbis 43-0x20,5
        rjmp .L2
        out 44-0x20,r24
/* epilogue start */
        ret
        .size   putch, .-putch
.global main
        .type   main, @function
main:
/* prologue: function */
/* frame size = 0 */
/* stack size = 0 */
.L__stack_usage = 0
        ldi r24,lo8(0)
        rcall putch
        ldi r24,lo8(1)
        rcall putch
        ldi r24,lo8(0)
        ldi r25,hi8(0)
/* epilogue start */
        ret


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31528