[Bug rtl-optimization/70261] [6 Regression] r234265 causes fails on rs6000

[rth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70261

Richard Henderson <rth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2016-03-17
                 CC|                            |rth at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #2 from Richard Henderson <rth at gcc dot gnu.org> ---
This also fails on aarch64 stage1 libstdc++, also during combine.

#1  0x000000000100dc90 in replace_rtx (x=0x3ffad2b58f8, from=0x3ffad2b1cb0, 
    to=0x3ffad2b5910) at ../../git-rh/gcc/rtlanal.c:2969
2969              gcc_assert (GET_MODE (x) == GET_MODE (from));
(gdb) call debug_rtx(x)
(reg:CC_NZ 66 cc)
(gdb) call debug_rtx(from)
(reg:CC 66 cc)

I'll attach the preprocessed for reference.