1049691 - IonMonkey: Fold loads with their stores.

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, defect)

Description

[Nicolas B. Pierron [:nbp]]

If we want to remove stores, which is what is intended in Bug 1044202, we first need to remove the loads which are dependent on these stores.

Our alias analysis is not yet precise but it should be enough to handle dominated cases.

Comment 1

[Nicolas B. Pierron [:nbp]]

Attachment: Fold Loads to their store value when possible.

Comment 2

[Dan Gohman [:sunfish]]

Comment on attachment 8468594 [details] [diff] [review]
Fold Loads to their store value when possible.

Review of attachment 8468594 [details] [diff] [review]:
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Fun!

Comment 3

[Nicolas B. Pierron [:nbp]]

Attachment: Fold Loads to their store value when possible.

Comment 4

[Nicolas B. Pierron [:nbp]]

https://treeherder.mozilla.org/ui/#/jobs?repo=try&revision=e74d30e420b8

The above patch fix a sanity issue reported by evilpie, which is that MLoadFixedSlot::flodsTo was not checking the slot index, as other instructions are doing.  Fortunately, this does not break anything as the alias analysis will only set as a dependency either an instruction which has the same slot (mightAlias) or an instruction which alias everything.

Comment 5

[Nicolas B. Pierron [:nbp]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/c5132b91b9ba

Comment 6

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/c5132b91b9ba