[Bug tree-optimization/50204] [4.5/4.6/4.7 Regression] Missed fully redundant load found in crafty (SPEC 2k)

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50204

--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-08-29 07:57:29 UTC ---
On a 2nd thought the work should be still linear, even for N PHI args the
way the merging is constructed (one arg has to dominate the other - the
only exception is the diamond case which has a constant cost of two).

So with some cleanup (essentially peel the first iteration of the loop)
the patch should be ok as-is.