[Bug rtl-optimization/47028] [4.6 Regression] gcc.dg/tree-ssa/tailrecursion-[57].c FAIL with -foptimize-sibling-calls -fno-forward-propagate -fno-tree-copy-prop -fno-tree-dominator-opts

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47028

--- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2010-12-30 
18:57:10 UTC ---
(In reply to comment #4)
> Created attachment 22869 [details]
> gcc46-pr47028.patch
> 
> Untested fix.

While the patch looks reasonable I wonder why we can't get rid of degenerate
PHI nodes in cfgcleanup (I wondered so multiple times) - of course we
have to avoid destroying loop-closed SSA form.