[Bug target/105334] New: [12 Regression] ICE in curr_insn_transform, at lra-constraints.cc:4168 (error: unable to generate reloads)

["asolokha at gmx dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105334

            Bug ID: 105334
           Summary: [12 Regression] ICE in curr_insn_transform, at
                    lra-constraints.cc:4168 (error: unable to generate
                    reloads)
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: accepts-invalid, ice-on-invalid-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
                CC: bergner at gcc dot gnu.org, linkw at gcc dot gnu.org,
                    segher at gcc dot gnu.org
  Target Milestone: ---
            Target: powerpc-*-linux-gnu

gcc 12.0.1 20220417 snapshot (g:000c1b89d259fadb466e1f2e63c79da45fd17372) ICEs
when compiling the following testcase, reduced from
gcc/testsuite/gcc.target/powerpc/pack02.c, w/ -mcpu=401:

long double
foo (void)
{
  return __builtin_pack_longdouble (1.0, 1.0);
}

% powerpc-e300c3-linux-gnu-gcc-12.0.1 -mcpu=401 -c eqozx4uz.c
eqozx4uz.c: In function 'foo':
eqozx4uz.c:5:1: error: unable to generate reloads for:
    5 | }
      | ^
(insn 7 6 10 2 (set (reg:TF 117 [ _1 ])
        (unspec:TF [
                (reg:DF 119)
                (reg:DF 120)
            ] UNSPEC_PACK_128BIT)) "eqozx4uz.c":4:10 1070 {packtf}
     (expr_list:REG_DEAD (reg:DF 120)
        (expr_list:REG_DEAD (reg:DF 119)
            (nil))))
during RTL pass: reload
eqozx4uz.c:5:1: internal compiler error: in curr_insn_transform, at
lra-constraints.cc:4168
0x690c51 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220417/work/gcc-12-20220417/gcc/rtl-error.cc:108
0x66b2b7 curr_insn_transform
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220417/work/gcc-12-20220417/gcc/lra-constraints.cc:4168
0xc9a615 lra_constraints(bool)
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220417/work/gcc-12-20220417/gcc/lra-constraints.cc:5203
0xc848ba lra(_IO_FILE*)
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220417/work/gcc-12-20220417/gcc/lra.cc:2375
0xc3b989 do_reload
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220417/work/gcc-12-20220417/gcc/ira.cc:5940
0xc3b989 execute
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-12.0.1_p20220417/work/gcc-12-20220417/gcc/ira.cc:6126