[PATCH] RISC-V: Define LOGICAL_OP_NON_SHORT_CIRCUIT to 1 [PR116615]

[Andrew Waterman]

On Wed, Oct 2, 2024 at 4:41 PM Jeff Law <jeffreyalaw@gmail.com> wrote:
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>
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> On 10/2/24 4:39 PM, Andrew Waterman wrote:
> > On Wed, Oct 2, 2024 at 5:56 AM Jeff Law <jeffreyalaw@gmail.com> wrote:
> >>
> >>
> >>
> >> On 9/5/24 12:52 PM, Palmer Dabbelt wrote:
> >>> We have cheap logical ops, so let's just move this back to the default
> >>> to take advantage of the standard branch/op hueristics.
> >>>
> >>> gcc/ChangeLog:
> >>>
> >>>        PR target/116615
> >>>        * config/riscv/riscv.h (LOGICAL_OP_NON_SHORT_CIRCUIT): Remove.
> >> So on the BPI  this is a pretty clear win.  Not surprisingly perlbench
> >> and gcc are the big winners.  It somewhat surprisingly regresses x264,
> >> deepsjeng & leela, but the magnitudes are smaller.  The net from a cycle
> >> perspective is 2.4%.  Every benchmark looks better from a branch count
> >> perspective.
> >>
> >> So in my mind it's just a matter of fixing any testsuite fallout (I
> >> would expect some) and this is OK.
> >
> > Jeff, were you able to measure the change in static code size, too?
> > These results are very encouraging, but I'd like to make sure we don't
> > need to retain the current behavior when optimizing for size.
> Codesize is ever so slightly worse.  As in less than .1%.  Not worth it
> in my mind to do something different in that range.

Thanks.  Agreed.

>
> Jeff