[Bug rtl-optimization/106707] [13 Regression] ICE: in cselib_record_set, at cselib.cc:2687 with -Oz -g -fno-cprop-registers -fno-dce

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106707

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-08-22
   Target Milestone|---                         |13.0
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
The insn we choke on is

(insn 196 160 155 5 (parallel [
            (set (reg:DI 0 ax [orig:91 _10 ] [91])
                (reg:DI 0 ax))
            (set (reg:DI 0 ax)
                (reg:DI 0 ax [orig:91 _10 ] [91]))
        ]) "t.c":13:12 95 {swapdi}
     (expr_list:REG_UNUSED (reg:DI 0 ax)
        (expr_list:REG_UNUSED (reg:DI 0 ax [orig:91 _10 ] [91])
            (nil))))

I also note the strange no-op swap here.  Possibly cselib doesn't like this
and/or that ax is possibly undefined.

Note this is the var-tracking cselib invocation.