[Bug other/92090] [10 regression] ICE in gcc.dg/atomic/c11-atomic-exec-5.c starting with r276469

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92090

--- Comment #7 from Segher Boessenkool <segher at gcc dot gnu.org> ---
LRA creates

;; Insn is not within a basic block
(insn 7037 0 0 (set (reg:PTI 3703)
        (const_wide_int 0x3ff00000000000000000000000000000)) -1
     (nil))

but that is not a valid insn.

This started as

(insn 3756 3755 3757 363 (set (reg:TI 2388)
        (const_wide_int 0x3ff00000000000000000000000000000))
"c11-atomic-exec-5.c":406:1 1179 {vsx_movti_64bit}
     (expr_list:REG_EQUIV (const_wide_int 0x3ff00000000000000000000000000000)
        (nil)))

(insn 3758 3757 3759 363 (set (reg:PTI 2389)
        (subreg:PTI (reg:TI 2388) 0)) "c11-atomic-exec-5.c":406:1 623
{*movpti_ppc64}
     (expr_list:REG_EQUIV (const_wide_int 0x3ff00000000000000000000000000000)
        (nil)))

which is fine.  But we have no insns (in the md) to load an immediate into
a PTI reg.