On Thu, Mar 19, 2015 at 8:44 AM, Jakub Jelinek <ja...@redhat.com> wrote:
> On Wed, Mar 18, 2015 at 08:00:33PM +0100, Uros Bizjak wrote:
>> 2015-03-18 Uros Bizjak <ubiz...@gmail.com>
>>
>> PR rtl-optimization/60851
>> * recog.c (constrain_operands): Accept a pseudo register before reload
>> for LRA enabled targets.
> As the two adjacent conditions are mostly the same, perhaps it might be
> better written as
> || ((/* Before reload, accept a pseudo, since
> LRA can turn it into a mem.
> (targetm.lra_p () && strict < 0)
> /* During reload, accept a pseudo. */
> || reload_in_progress)
> && REG_P (op)
> && REGNO (op) >= FIRST_PSEUDO_REGISTER)))
>
> or put REG_P && REGNO checks first and only then test when.
Yeah, I thought about this particular CSE a bit. But since these are
two conceptually different conditions, and the formatting (and
comments) just didn't fit into available space, I wrote it this way.
IMO, it is more readable, better follows the intended logic, and
avoids even more indents.
Also, I am pretty sure that any decent compiler can CSE this part on its own.
However, the condition can be slightly improved by rewriting it to:
/* Before reload, accept a pseudo,
since LRA can turn it into a mem. */
|| (strict < 0 && targetm.lra_p () && REG_P (op)
&& REGNO (op) >= FIRST_PSEUDO_REGISTER)
so, we have cheaper tests in the front to shortcut more expensive tests later.
> For 4.9 backport, please wait a few days after it goes into the trunk.
Thanks!
Uros.
