Eliminate unnecessary LoadUnboxedExpando

RESOLVED FIXED in Firefox 52

Status

()

defect
P2
normal
RESOLVED FIXED
3 years ago
3 years ago

People

(Reporter: jandem, Assigned: jandem)

Tracking

(Blocks 1 bug)

unspecified
mozilla52
Points:
---
Dependency tree / graph

Firefox Tracking Flags

(firefox52 fixed)

Details

Attachments

(1 attachment)

Assignee

Description

3 years ago
Posted patch PatchSplinter Review
LoadUnboxedExpando is redundant with the GuardAndLoadUnboxedExpando we emit first. I was aware of this when I added LoadUnboxedExpando but decided to match what the Ion ICs do (they have a similar issue). It's easy to fix for CacheIR though: we can simply return the expandoId from TestMatchingReceiver and reuse that.

I confirmed this eliminates a load on x86 and x64.
Attachment #8804623 - Flags: review?(hv1989)
Comment on attachment 8804623 [details] [diff] [review]
Patch

Review of attachment 8804623 [details] [diff] [review]:
-----------------------------------------------------------------

Glad it works out! Nice removal with perf benefits :D

::: js/src/jit/BaselineInspector.cpp
@@ +112,5 @@
>      // We match either:
>      //
>      //   GuardIsObject 0
>      //   GuardShape 0
> +    //   LoadFixedSlotResult 0 or LoadDynamicSlotResult 0

Nice
Attachment #8804623 - Flags: review?(hv1989) → review+
I assume this depends on the other CacheIR bug. Therefore marking it as P2. I'll review the other bug today again.
Priority: -- → P2

Comment 3

3 years ago
Pushed by jandemooij@gmail.com:
https://hg.mozilla.org/integration/mozilla-inbound/rev/f3b662e19b24
Remove unnecessary LoadUnboxedExpando. r=h4writer

Comment 4

3 years ago
bugherder
https://hg.mozilla.org/mozilla-central/rev/f3b662e19b24
Status: ASSIGNED → RESOLVED
Last Resolved: 3 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla52
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