[Bug target/50106] [ARM] Wrong code with -march=armv5t -mthumb -Os

["sebastian dot huber at embedded-brains dot de" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50106

--- Comment #4 from Sebastian Huber <sebastian.huber@embedded-brains.de> 2011-08-22 09:43:39 UTC ---
Yes, this patch fixes the problem.

It is still not clear to me why we save the volatile registers r0, r1, and r2
at all.  Also we restore r1, r2, and r3.  Does this make sense?  I think also
the the usage of memcpy() is not justified in this case.

_Z7_GetIDSj:
        .fnstart
.LFB0:
        .save   {r0, r1, r2, lr}
        push    {r0, r1, r2, lr}
        ldr     r1, .L4
        cmp     r0, #3
        bhi     .L2
        lsl     r0, r0, #1
        add     r1, r1, r0
.L2:
        mov     r2, #2
        add     r0, sp, #4
        bl      memcpy
        add     r3, sp, #4
        ldrb    r0, [r3, #1]
        ldrb    r2, [r3]
        lsl     r0, r0, #8
        orr     r0, r2
        @ sp needed for prologue
        pop     {r1, r2, r3, pc}