Testing and branching with different modes

[Paulo Matos]

Hello,

My port seems to be slightly awkward in testing and branching compared to the 
existing one in mainline.
All the comparisons in my port set a QImode (8bits) register (predicate 
register), however branches branch on a single bit value of the predicate 
register.

So while I have:
tsteqb p0, r0, r1

which sets p0 to 0xff is r0 == r1, then the branch looks like
bl p0.<bit>, <label>, 
where
bl p0.0, L1

branches to L1 is bit 0 of p0 is set.

So I have cmp_qimode, etc but then only cbranchbi4.

My cbranchbi4 should look like this:
(define_insn "cbranchbi4"
  [(set (pc)
        (if_then_else
         (match_operator 0 " easy_comparison"
                         [(subreg:BI (match_operand:QI 1 "register" "c") 0)
                          (match_operand:BI 2 "const0"   "")])
         (label_ref (match_operand 3 "" ""))
         (pc)))]
  ""...

or
(define_insn "cbranchbi4"
  [(set (pc)
        (if_then_else
         (match_operator 0 " easy_comparison"
                         [(and:BI (match_operand:QI 1 " register" "c")
                                  (const_int 1))
                          (match_operand:BI 2 "const0"   "")])
         (label_ref (match_operand 3 "" ""))
         (pc)))]
  ""...


but both of these alternatives don't seem to be supported as it causes an ICE 
in patch_jump_insn.
What's the best way to deal with this situation? Is there any port out there 
with similar issues?

Cheers,

Paulo Matos