This is a reland of 863bc2b88a
Diff to original:
- Don't eliminate GC observable stores that were temporarily
unobservable during traversal.
- Skip the previously added test for single-generation
- Add new test
Original change's description:
> [turbofan] Improve StoreStoreElimination
>
> Previously, StoreStoreElimination handled allocations as
> "can observe anything". This is pretty conservative and prohibits
> elimination of repeated double stores to the same field.
> With this CL allocations are changed to "observes initializing or
> transitioning stores".
> This way it is guaranteed that initializing stores to a freshly created
> object or stores that are part of a map transition are not eliminated
> before allocations (that can trigger GC), but allows elimination of
> non-initializing, non-transitioning, unobservable stores in the
> presence of allocations.
>
> Bug: v8:12200
> Change-Id: Ie1419696b9c8cb7c39aecf38d9f08102177b2c0f
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3295449
> Commit-Queue: Patrick Thier <pthier@chromium.org>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Reviewed-by: Maya Lekova <mslekova@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#78230}
Bug: v8:12200, chromium:1276923, v8:12477
Change-Id: Ied45ee28ac12b370f7b232d2d338f93e10fea6b4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3320460
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Patrick Thier <pthier@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78349}
This reverts commit 863bc2b88a.
Reason for revert: https://crbug.com/1276923
Original change's description:
> [turbofan] Improve StoreStoreElimination
>
> Previously, StoreStoreElimination handled allocations as
> "can observe anything". This is pretty conservative and prohibits
> elimination of repeated double stores to the same field.
> With this CL allocations are changed to "observes initializing or
> transitioning stores".
> This way it is guaranteed that initializing stores to a freshly created
> object or stores that are part of a map transition are not eliminated
> before allocations (that can trigger GC), but allows elimination of
> non-initializing, non-transitioning, unobservable stores in the
> presence of allocations.
>
> Bug: v8:12200
> Change-Id: Ie1419696b9c8cb7c39aecf38d9f08102177b2c0f
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3295449
> Commit-Queue: Patrick Thier <pthier@chromium.org>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Reviewed-by: Maya Lekova <mslekova@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#78230}
Bug: chromium:1276923
Change-Id: I43dc3572ce1ef1fda42b7551ce8210d9f03e36ca
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3318666
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Patrick Thier <pthier@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78277}
Previously, StoreStoreElimination handled allocations as
"can observe anything". This is pretty conservative and prohibits
elimination of repeated double stores to the same field.
With this CL allocations are changed to "observes initializing or
transitioning stores".
This way it is guaranteed that initializing stores to a freshly created
object or stores that are part of a map transition are not eliminated
before allocations (that can trigger GC), but allows elimination of
non-initializing, non-transitioning, unobservable stores in the
presence of allocations.
Bug: v8:12200
Change-Id: Ie1419696b9c8cb7c39aecf38d9f08102177b2c0f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3295449
Commit-Queue: Patrick Thier <pthier@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78230}
