A question about thumb2 cbnz/cbz implementation in thumb2.md

[Revital1 Eres]

Hello,

I have a question about cbnz/cbz thumb-2 instruction implementation in
thumb2.md file:

I have an example where we jump to a label which appears before the branch;
for example:

        L4
        ...
        cmp     r3, 0
        bne     .L4

It seems that cbnz instruction should be applied in this loop; replacing
cmp+bne; however, cbnz fails to be applied as diff = ADDRESS (L4) - ADDRESS
(bne .L4) is negative and according to thumb2_cbz in thumb2.md it should
be 2<=diff<=128 (please see snippet below taken from thumb2_cbz).

So I want to double check if the current implementation of thumb2_cbnz
in thumb2.md needs to be changed to enable it.

The following is from thumb2_cbnz in thumb2.md:

  [(set (attr "length")
        (if_then_else
            (and (ge (minus (match_dup 1) (pc)) (const_int 2))
                 (le (minus (match_dup 1) (pc)) (const_int 128))
                 (eq (symbol_ref ("which_alternative")) (const_int 0)))
            (const_int 2)
            (const_int 8)))]

Thanks,
Revital