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[SDAG] Update generic code to conservatively check for isAtomic in addition to isVolatile

Authored by reames on Aug 15 2019, 4:07 PM.



See D66309 for context.

This is the first sweep of generic code to add isAtomic bailouts where appropriate. The intention here is to have the switch from AtomicSDNode to LoadSDNode/StoreSDNode be close to NFC; that is, I'm not looking to allow additional optimizations at this time. That will come later.

(Note: This is currently based on ToT without D66309. That's why there are no test diffs with the experimental flag visible. It could be added either before or after that change.)

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reames created this revision.Aug 15 2019, 4:07 PM
Herald added a project: Restricted Project. · View Herald TranscriptAug 15 2019, 4:07 PM
reames updated this revision to Diff 215493.Aug 15 2019, 4:13 PM

update all todos with an easily grepable tag for ease of future work

reames planned changes to this revision.Sep 9 2019, 1:29 PM

Waiting behind D66322 since that's where discussion has happened. Once that's in, will rebase with the same changes here.

Porting a comment from craig.topper over on D66322:
"Will you also be updating nonvolatile_load/nonvolatile_store in include/llvm/Target/ We use those in several places where we change the size of a load."

Needs addressed in rebase.

reames updated this revision to Diff 219583.Sep 10 2019, 12:22 PM

Rebase to include isSimple usage, and test updates.

Still need to include the nonvolatile_load/nonvolatile_store cases. Need access to a larger build machine for that one. :)

reames updated this revision to Diff 219585.Sep 10 2019, 12:35 PM

Add the nonvolatile_load/store cases. I'll rename them in a separate commit so as not to clutter the diff on this one.

With that, we're catching *most* of the atomic vs non-atomic differences. Skimming the remaining test diffs, I clearly need to adjust my test lines to hide O3 vs experimental O3 differences. There do appear to be a few remaining cases that are being miscompiled, mostly around widenable store idioms. Need to track that down in a future patch.

arsenm accepted this revision.Sep 12 2019, 3:12 PM
arsenm added a subscriber: arsenm.

LGTM with nits

14036 ↗(On Diff #219585)

Capitalize comment

16320 ↗(On Diff #219585)


16332 ↗(On Diff #219585)


16464 ↗(On Diff #219585)


This revision is now accepted and ready to land.Sep 12 2019, 3:12 PM
This revision was automatically updated to reflect the committed changes.