When the scratch registers are disabled, any instruction that uses them should CRASH. This should be used by Air::generate().
Created attachment 266255 [details]
Created attachment 266256 [details]
r=me as well.
Landed in http://trac.webkit.org/changeset/192812
Re-opened since this is blocked by bug 151669
This definitely relanded, don't remember when, but it was a long time ago.