>$ g++ -O3 -march=skylake-avx512 -c func.cpp
func.cpp: In function ‘void test(short unsigned int, unsigned char, long long int)’:
func.cpp:13:1: error: could not split insn
   13 | }
      | ^
(insn 644 21 817 50 (set (reg:DI 70 k2 [orig:83 D.4406 ] [83])
        (zero_extend:DI (not:SI (reg:SI 70 k2 [orig:505 b ] [505])))) "func.cpp":10:18 622 {*one_cmplsi2_1_zext}
     (nil))
during RTL pass: final
func.cpp:13:1: internal compiler error: in final_scan_insn_1, at final.c:3073
0x7cf5e7 _fatal_insn(char const*, rtx_def const*, char const*, int, char const*)
	/gcc/rtl-error.c:108
0x75b978 final_scan_insn_1
	/gcc/final.c:3073
0xd9b5cf final_scan_insn(rtx_insn*, _IO_FILE*, int, int, int*)
	/gcc/final.c:3152
0xd9b8c7 final_1
	/gcc/final.c:2020
0xd9c298 rest_of_handle_final
	/gcc/final.c:4658
0xd9c298 execute
	/gcc/final.c:4736


Reproducer:
extern long var_22;
extern int arr_3[];
extern int arr_4[][20][9];
short a;
void test(unsigned short b, unsigned char e, long long g) {
  for (long c = 0; c < 20ULL; c = g)
    for (short d = 0; d < 9; d++)
      for (char f = e; f < 8; f += 4) {
        arr_3[f] = 0;
        var_22 = ~(unsigned)b;
        arr_4[c][d][f] = a;
      }
}

gcc version 11.0.0 20200823 (87c753ac241f25d222d46ba1ac66ceba89d6a200)