On 11/18/2014 11:48 AM, Yangfei (Felix) wrote:
> +(define_expand "doloop_end"
> + [(use (match_operand 0 "" "")) ; loop pseudo
> + (use (match_operand 1 "" ""))] ; label
> + ""
> +{
> + /* Currently SMS relies on the do-loop pattern to recognize loops
> + where (1) the control part consists of all insns defining and/or
> + using a certain 'count' register and (2) the loop count can be
> + adjusted by modifying this register prior to the loop.
> + ??? The possible introduction of a new block to initialize the
> + new IV can potentially affect branch optimizations. */
> + if (optimize > 0 && flag_modulo_sched)
You'd be better off moving this condition into the expansion predicate (which
is currently "").
This short-circuits a lot of unnecessary work. See pass_rtl_doloop::gate.
r~
