[RISCV][RFC/WIP] Enable load clustering in SelectionDAG scheduler #74600
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
asb
changed the title
…ustering Reordering based on the sort order of the MemOpInfo array was disabled in <https://reviews.llvm.org/D72706>. However, it's not clear this is desirable for al targets. It also makes it more difficult to compare the incremental benefit of enabling load clustering in the selectiondag scheduler as well was the machinescheduler, as the sdag scheduler does seem to allow this reordering. This patch adds a parameter that can control the behaviour on a per-target basis.
Split out from llvm#73789. Clusters if the operations are within a cache line of each other (as AMDGPU does in shouldScheduleLoadsNear). X86 does something similar, but does `((Offset2 - Offset1) / 8 > 64)`. I'm not sure if that's intentionally set to 512 bytes or if the division is in error. Adopts the suggestion from @wangpc-pp to query the cache line size and use it if available.
asb
force-pushed
the
2023q4-riscv-cluster-memops-3-with-sdag-clustering
branch
from
d3850e7
to
044d1d8
Compare
asb
force-pushed
the
2023q4-riscv-cluster-memops-3-with-sdag-clustering
branch
from
044d1d8
to
91299d4
Compare
|
Rebased on top of #73789 to make this easier to analyse. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Builds on top of #73789.
Many changes are just noise (slightly different register choice), but there do seem to be some cases where additional clustering is taking place that I want to investigate further.
If we can get by with clustering in just the MachineScheduler, that would be preferable.
Posting at this point primarily for others to reference, not ready for direct review.