Comment # 9 on bug 90056 from Grigori Goronzy

Created attachment 115409 [details] [review]
Full shader

That does not help either. Seems to break the SSA somehow. Full shader that
triggers the bug attached.

The patch I posted earlier help with the the reduced testcase, but not with the
full shader. Both undef incoming values in phi nodes and undef branch
conditions cause problems in different ways.