[PATCH] D128941: [ModuloSchedule] Add interface call to accept/reject SMS schedules

Mon Jul 18 15:26:50 PDT 2022

dpenry marked 5 inline comments as done.
dpenry added a comment.

In D128941#3627725 <https://reviews.llvm.org/D128941#3627725>, @dmgreen wrote:

> At a high level shouldUseSchedule sounds like a useful addition, but much of the logic in the current Arm implementation doesn't seem very Arm specific (correct me if I'm wrong). Would it be beneficial to incorporate the register pressure calculations into SwingSchedulerDAG, which the target could opt into checking.

The current logic isn't Arm-specific.  This might be useful more generally, but I'd like to see more feedback before adding the calculations in.

================
Comment at: llvm/test/CodeGen/Thumb2/swp-regpressure.mir:6
+# schedule to be rejected and that a test with the same resource usage
+# but without register pressure is not rejected.
+
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dmgreen wrote:
> This test uses phi nodes to increase the register pressure? Maybe remove the dead phis from dot2.
> 
> And maybe rename the tests to make it clear that dot1 has too high pressure, but dot2 is OK and expected to pipeilne.
- Renamed the tests, but the point of using the phi nodes in this way -- including the dead phis -- was to have the same set of instructions in each case with the only difference being the register pressure induced by them.  Phi nodes are particularly nice because they don't affect RecMII.

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https://reviews.llvm.org/D128941