[Webkit-unassigned] [Bug 162124] Unite op_get_by_id_with_this with op_get_by_id

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=162124

--- Comment #20 from Caio Lima <ticaiolima at gmail.com> ---
(In reply to comment #19)
> Why would we do this?

If I didn't miss any context *_with_this were created to solve the bug on (https://bugs.webkit.org/show_bug.cgi?id=147064). The current implementationis just a call to slow paths "operation*WithThis", meaning that we don't use IC or PIC on "super.foo" for example.
Merging get_by_id_with_this with op_get_by_id we enable its optimization including IC and PIC. In terms of performance, now it means 20% faster over op_get_by_id_with_this version.

> It's definitely good for lower tiers that get_by_id does not take an extra
> this operand.  It's also easier to parse.  I don't understand why we would
> remove this optimization.

I didn't understand why it is easier to parse.
Also, About good parts of get_by_id does not take an extra this operand, do you mind explain me why? I can think that we use extra memory to store the this operand, which has a big impact because get_by_id is one of the most used op_codes.

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