On Thu, Mar 09, 2017 at 10:01:57AM +0000, Kyrill Tkachov wrote: > > On 08/03/17 17:39, James Greenhalgh wrote: > >On Mon, Mar 06, 2017 at 05:09:58AM +0000, Hurugalawadi, Naveen wrote: > >>Hi, > >> > >>Please find attached the patch that adds aes and sha reservations for > >>Thunderx2t99. > >> > >>Bootstrapped and Regression tested on aarch64-thunder-linux. > >>Please review the patch and let us know if its okay for Stage-1? > >> > >>Thanks, > >>Naveen > >> > >>2017-03-06 Julian Brown <jul...@codesourcery.com> > >> Naveen H.S <naveen.hurugalaw...@cavium.com> > >> > >> * config/aarch64/thunderx2t99.md (thunderx2t99_crc): New Reservation. > >>diff --git a/gcc/config/aarch64/thunderx2t99.md > >>b/gcc/config/aarch64/thunderx2t99.md > >>index f807547..2eb136b 100644 > >>--- a/gcc/config/aarch64/thunderx2t99.md > >>+++ b/gcc/config/aarch64/thunderx2t99.md > >>@@ -443,7 +443,22 @@ > >> (eq_attr "type" "neon_store2_one_lane,neon_store2_one_lane_q")) > >> "thunderx2t99_ls01,thunderx2t99_f01") > >>+;; Crypto extensions. > >>+ > >>+; FIXME: Forwarding path for aese/aesmc or aesd/aesimc pairs? > >Do you need these if you've enabled instruction fusion? > > I'd recommend it if one wants to bring the pairs together. > > >I'm not sure on the exact mechanics of how instruction fusion works, and > >whether you'd get further scheduling benefits from modeling a forwarding > >path if one exists. > > The (macro) fusion mechanism in the scheduler makes sure to keep > the pairs together if they appear together before scheduling, but doesn't > do anything to actually bring them together if they are far apart. > So having bypasses would encourage the scheduler to form pairs more > aggressively.
Thanks for the explanation, that is useful to know. James
