Paul Stoffregen <p...@pjrc.com> wrote:
> Indeed it works great with -O2. But with -Os, __builtin_constant_p
> never returns 1.
It appears to me GCC simply thinks inlining the function would not be
feasible with -Os -- well, partially at least. If you declare your
function as
static inline void __attribute__((always_inline))
digitalWrite(uint8_t pin, uint8_t val)
(thus overriding GCC's heuristics about inlining), it yields your
desired result:
main:
/* prologue: function */
/* frame size = 0 */
sbi 43-32,2
lds r24,num
ldi r22,lo8(1)
call _digitalWrite
sbi 43-32,2
..L2:
rjmp .L2
--
cheers, J"org .-.-. --... ...-- -.. . DL8DTL
http://www.sax.de/~joerg/ NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)
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