[Bug target/91469] New: [10 Regression] ICE in extract_insn, at recog.c:2310 since r274481

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91469

            Bug ID: 91469
           Summary: [10 Regression] ICE in extract_insn, at recog.c:2310
                    since r274481
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: rguenth at gcc dot gnu.org, uros at gcc dot gnu.org
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu

Yet another fallout from the the patch:

$ cat ice.i
int a, b, e;
long long c;
int d[6];

void fn1() {
  int i;
  unsigned f;
  c = a;
  f = i;
  for (; i < b; i++)
    if (d[i] > f)
      f = d[i];
  e = f;
}

$ gcc ice.i -funroll-loops -O2 -fno-gcse -m32 -mavx512vbmi -fno-ivopts
ice.i: In function ‘fn1’:
ice.i:14:1: error: unrecognizable insn:
   14 | }
      | ^
(insn 72 69 14 3 (set (reg:SI 115)
        (mem:SI (plus:SI (mult:SI (subreg:V4SI (reg:SI 114) 0)
                    (const_int 4 [0x4]))
                (symbol_ref:SI ("d") [flags 0x2] <var_decl 0x7f9229914cf0 d>))
[1 d S4 A32])) -1
     (nil))
during RTL pass: subreg3
ice.i:14:1: internal compiler error: in extract_insn, at recog.c:2310
0x6bab09 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        /home/marxin/Programming/gcc/gcc/rtl-error.c:108
0x6bab25 _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        /home/marxin/Programming/gcc/gcc/rtl-error.c:116
0x6b8cad extract_insn(rtx_insn*)
        /home/marxin/Programming/gcc/gcc/recog.c:2310
0x16d1af7 decompose_multiword_subregs
        /home/marxin/Programming/gcc/gcc/lower-subreg.c:1540
0x16d2c2d execute
        /home/marxin/Programming/gcc/gcc/lower-subreg.c:1808
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