Summary:
Most CPUs implementing AES fusion require instruction pairs of the form
AESE Vn, _
AESMC Vn, Vn
and
AESD Vn, _
AESIMC Vn, Vn
The constraint is added to AES(I)MC instructions which use the result of
an AES(E|D) instruction by using AES(I)MCTrr pseudo instructions, which
constraint source and destination registers to be the same.
A nice side effect of this change is that now all possible pairs are
scheduled back-to-back on the exynos-m1 for the misched-fusion-aes.ll
test case.
I had to update aes_load_store. The version I added initially was very
reduced and with the new constraint, AESE/AESMC could not be scheduled
back-to-back. I updated the test to be more realistic and still expose
the same scheduling problem as the initial test case.
Reviewers: t.p.northover, rengolin, evandro, kristof.beyls, silviu.baranga
Reviewed By: t.p.northover, evandro
Subscribers: aemerson, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D35299
llvm-svn: 309495
Summary:
Scheduling AESE/AESMC and AESD/AESIMC instruction pairs back-to-back
gives a double digit speedup on benchmarks using those instructions on
Cortex-A processors. In GCC, this optimization is part of the generic
processor model as well.
This change should not have a major performance impact on processors
that do not optimize AES instruction pairs, although I only had access
to Cortex-A processors for benchmarking.
Reviewers: rengolin, kristof.beyls, javed.absar, evandro, silviu.baranga, MatzeB, mcrosier, joelkevinjones, joel_k_jones, bmakam, t.p.northover
Reviewed By: evandro
Subscribers: sbaranga, aemerson, llvm-commits
Differential Revision: https://reviews.llvm.org/D33836
llvm-svn: 305457
Summary:
This patch makes instruction fusion more aggressive by
* adding artificial edges between the successors of FirstSU and
SecondSU, similar to BaseMemOpClusterMutation::clusterNeighboringMemOps.
* updating PostGenericScheduler::tryCandidate to keep clusters together,
similar to GenericScheduler::tryCandidate.
This change increases the number of AES instruction pairs generated on
Cortex-A57 and Cortex-A72. This doesn't change code at all in
most benchmarks or general code, but we've seen improvement on kernels
using AESE/AESMC and AESD/AESIMC.
Reviewers: evandro, kristof.beyls, t.p.northover, silviu.baranga, atrick, rengolin, MatzeB
Reviewed By: evandro
Subscribers: aemerson, rengolin, MatzeB, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D33230
llvm-svn: 303618
This patch enables fusing dependent AESE/AESMC and AESD/AESIMC
instruction pairs on Cortex-A72, as recommended in the Software
Optimization Guide, section 4.10.
llvm-svn: 303073
Evandro Menezes