Question about conds attribute for *thumb2_alusi3_short

[Tom de Vries]

Richard,

I've noticed that f.i. *thumb2_alusi3_short has no explicit setting of the conds
attribute, which means the value of the conds attribute for this insn is nocond:
...
(define_insn "*thumb2_alusi3_short"
  [(set (match_operand:SI          0 "s_register_operand" "=l")
        (match_operator:SI 3 "thumb_16bit_operator"
         [(match_operand:SI 1 "s_register_operand" "0")
          (match_operand:SI 2 "s_register_operand" "l")]))
   (clobber (reg:CC CC_REGNUM))]
  "TARGET_THUMB2 && reload_completed
   && GET_CODE(operands[3]) != PLUS
   && GET_CODE(operands[3]) != MINUS"
  "%I3%!\\t%0, %1, %2"
  [(set_attr "predicable" "yes")
   (set_attr "length" "2")]
)
...

AFAIU, this insn is either:
- conditional, and does not modify cc, or
- unconditional, and sets cc.
So the clobber of CC in the RTL conservatively describes both cases.

It seems to me the logical conds setting for the conditional case is nocond, set
(or perhaps clob) for the unconditional case. So, is this a more accurate value
of conds for this insn:
...
   (set (attr "conds")
        (if_then_else
          (match_test "GET_CODE (PATTERN (insn)) == COND_EXEC")
          (const_string "nocond")
          (const_string "set")))]
...
?

Is there a generic need to have this attribute accurate for all insns?

Thanks,
- Tom