[Bug target/56219] avr-gcc-4.7.2 missing __uint24 loop optimisation

[demiurg_spb at freemail dot ru]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56219



--- Comment #1 from demiurg_spb at freemail dot ru 2013-02-06 12:34:53 UTC ---

It would be optimal move outside loop all extra instructions, and use temp

register r0 more active.



    ldi r24,0

    ldi r25,lo8(4)                     // outside loop

.L2:

    mov r30,r24

    andi r30,lo8(7)

    mul r30,r25

    movw r30,r0

    subi r30,lo8(-(br.1322))

    sbci r31,hi8(-(br.1322))

    lpm r0,Z                           // use r0 as temp

    sts 100,r0

    subi r24,lo8(-(1))

    rjmp .L2

    clr __zero_reg__                   // outside loop