[Bug rtl-optimization/81288] [5/6/7/8 Regression] ICE on 32-bit BE powerpc targets -w -misel -O2 (-O3, -Ofast, -Os)

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81288

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-07-10
     Ever confirmed|0                           |1

--- Comment #1 from Segher Boessenkool <segher at gcc dot gnu.org> ---
It doesn't fail for me, -misel, either -m32 or -m64, either -O2, -Os, -O3,
not with trunk and also not with four weeks ago.

Ah.  With -mcpu=8548 it segfaults.

It is some unbounded recursion:

#62 0x000000001118bd14 in fold_rtx (x=0x3fffb6bf2130, insn=insn@entry=0x0)
    at /home/segher/src/gcc/gcc/cse.c:3411

Joy, corrupted stack.  "x" seems to be some isel (no surprise really),
probably this one (because it's the only isel in the whole program):

(insn 22 21 23 5 (set (reg:SI 137)
        (if_then_else:SI (eq (reg:CC 138)
                (const_int 0 [0]))
            (const_int 0 [0])
            (reg:SI 139))) "81288.c":8 330 {isel_signed_si}
     (nil))

Anyway, confirmed.