[Bug target/82016] [8 regression] test case gcc.target/powerpc/float128-type-1.c fails after r251260

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82016

Segher Boessenkool <segher at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-08-28
     Ever confirmed|0                           |1

--- Comment #5 from Segher Boessenkool <segher at gcc dot gnu.org> ---
The ccp1 pass makes it return 0 instead of a+b:

===
Simulating block 2

Visiting statement:
_3 = a_1(D) + b_2(D);
which is likely CONSTANT
Match-and-simplified a_1(D) + b_2(D) to 0.0
Lattice value changed to CONSTANT 0.0.  Adding SSA edges to worklist.
marking stmt to be not simulated again
===

Confirmed.  (float128-type-2.c fails in the same way).