[Bug target/40730] redundant memory load

[carrot at google dot com]

------- Comment #12 from carrot at google dot com  2010-01-11 08:55 -------
(In reply to comment #11)
> Yes, I would have expected the block starting with .L4 to be *after*
> the block starting with .L5, something like so:
> 
> iterate:
>         push    {lr}
>         ldr     r3, [r1]
> .L6:
>         str     r3, [r0]
>         sub     r2, r3, #0
>         beq     .L3
> .L5:
>         ldr     r1, [r3, #4]
>         cmp     r1, #0
>         bne     .L3
>         ldr     r3, [r3, #8]
>         b       .L6
> .L3:
>         str     r2, [r0, #12]
>         @ sp needed for prologue
>         pop     {pc}
> 
> Does that look correct?  And if so, could you see if there is an open
> bug report about this; or otherwise file a new PR and add me to the
> CC-list?
> 

It is correct. The basic block ordering issue (-Os) has been observed several
times. Following are related PRs:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41004
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41396


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40730