On 10/4/24 12:42 AM, Richard Biener wrote:
On Thu, Oct 3, 2024 at 3:15 AM Andrew Waterman <and...@sifive.com> wrote:
On Wed, Oct 2, 2024 at 4:41 PM Jeff Law <jeffreya...@gmail.com> wrote:
On 10/2/24 4:39 PM, Andrew Waterman wrote:
On Wed, Oct 2, 2024 at 5:56 AM Jeff Law <jeffreya...@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.
It probably helps code-size when not optimizing for size depending on
how you align jumps.
By default we aren't aligning jumps at all. The infrastructure is in
place to allow uarchs to select their preferences though (we're using
that infrastructure internally).
jeff
