[Bug rtl-optimization/44025] Multiple load 0 to register

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44025

--- Comment #7 from Steven Bosscher <steven at gcc dot gnu.org> 2012-07-24 18:16:17 UTC ---
Prototype patch attached to this email:
http://gcc.gnu.org/ml/gcc/2012-07/msg00189.html

It's not a finished patch, but it should be a good starting point for anyone
who really wants to fix this problem:

bar4:   
        @ args = 0, pretend = 0, frame = 0
        @ frame_needed = 0, uses_anonymous_args = 0
        mov     r3, r0
        ldr     r0, [r0, #520]
        push    {r4, r5, r6, lr}
        mov     r2, r3
        mov     r1, r3
        adds    r0, r3, r0
        movs    r6, #0
        b       .L9
.L4:
        ldrb    r5, [r2], #1    @ zero_extendqisi2
        cmp     r5, #10
        bne     .L9
        mov     r1, r2
        movs    r4, #0
        strb    r6, [r2, #-1]
.L9:
        subs    r5, r0, r2
        cmp     r5, #0
        bgt     .L4
        cmp     r1, r3
        bne     .L5
        strb    r4, [r1, #512]
        pop     {r4, r5, r6, pc}
.L10:   
        subs    r4, r1, r3
        mov     r0, r3
        mov     r2, r4
        bl      memmove
        mov     r3, r0
.L11:   
        str     r4, [r3, #520]
        pop     {r4, r5, r6, pc}
.L5:
        ldr     r2, [r3, #520]
        adds    r2, r3, r2
        cmp     r1, r2
        bcs     .L11
        b       .L10