It's not needed anymore now that the compiler is concurrent - we're just not sensitive to such compile-time hacks anymore.
This blocks https://bugs.webkit.org/show_bug.cgi?id=124138 because I'm pretty sure the fix to that requires making ConstantFoldingPhase do some special things for folded GetLocal's. Currently it's already doing *really insane* special things for folded GetLocal's, and I don't want to put special things on top of special things.
Created attachment 216615 [details] the patch
Comment on attachment 216615 [details] the patch r=me assuming benchmarks look good.
Landed in http://trac.webkit.org/changeset/159074