fourthTier: GC's put_by_id transition fixpoint should converge more quickly
https://bugs.webkit.org/show_bug.cgi?id=117912
Reviewed by Mark Hahnenberg.
This was a rookie mistake. The GC does a classic forward data flow fixpoint. These work well so long as you
iterate the program in program order, or at least something close to program order. Because I enjoy reverse
loops ("while (n--) blah"), I ended up iterating in *reverse* of program order which ensured worst-case
pathologies every single time. And unsurprisingly, this slowed down a program, namely pdfjs.
Flipping the loops to iterate forward fixes a 90% regression in Octane/pdfjs and is otherwise neutral.
* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::propagateTransitions):
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153243 268f45cc-cd09-0410-ab3c-d52691b4dbfc
2 files changed
