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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - JavaScriptCore deeply nested "call" performance issue"
href="https://bugs.webkit.org/show_bug.cgi?id=139847#c7">Comment # 7</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - JavaScriptCore deeply nested "call" performance issue"
href="https://bugs.webkit.org/show_bug.cgi?id=139847">bug 139847</a>
from <span class="vcard"><a class="email" href="mailto:fpizlo@apple.com" title="Filip Pizlo <fpizlo@apple.com>"> <span class="fn">Filip Pizlo</span></a>
</span></b>
<pre>(In reply to <a href="show_bug.cgi?id=139847#c6">comment #6</a>)
<span class="quote">> My guess is we're recursively emitting bytecode in a way that has
> exponential blowup.</span >
Yeah that's totally what's happening. That's hilarious.
We should just have a back-off on that optimization. Like, maintain a count of how deep in the "doubling" due to .call, .apply, or other jneq_ptr-based opts. If more than K deep then don't do the optimization.
Probably the most optimal way to do it would be upside down: don't do the optimization if there are more than K people below you in the tree who want to do it, so that the optimization kicks in for the leaves of that gross call tree.</pre>
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