[Bug middle-end/46555] [4.9/5/6 Regression] PHI RTL expansion leads to CSiBE regression

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46555

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
The idea is to add forwarder blocks here.  Of course doing this too
aggressively may be bad, not sure (extra jumps instead of extra copies). 
Eventually the
targets want some control on this.