LICM should gracefully handle unprofiled code

[Filip Pizlo]

Consider:

loop {
    if (never happens)
        o.f++; // this thing
}

This thing will look like a clobber-the-world side-effect.  But, it's also an exit site.  I don't think that the IR makes clear that that basic block doesn't belong in the loop.  We should investigate this more.

[Filip Pizlo]

Created attachment 223818 [details]
the patch

[Mark Hahnenberg]

Comment on attachment 223818 [details]
the patch

r=me

[Filip Pizlo]

Landed in http://trac.webkit.org/changeset/163879