[Bug target/112871] [14 Regression] RISCV ICE: in extract_insn, at recog.cc:2804 (unrecognizable insn) with -03 rv32gc_zicond

["patrick at rivosinc dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112871

--- Comment #1 from Patrick O'Neill <patrick at rivosinc dot com> ---
Created attachment 56821
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56821&action=edit
testcase-2-freport-bug-output

Here's a different testcase that manifests the same error:
int a, b, d, e, c;
char *f;
static int g;
void h(long long i) {
  int *j = &g;
  ++*j;
k:
  if (c >> d) {
    e = a % b;
    (*j = i) && ++*j;
    *f |= 1;
    if (i)
      goto k;
  }
}

> /scratch/tc-testing/tc-dec-6-trunk/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc -march=rv32gcv_zicond -mabi=ilp32d -O1 red.c -freport-bug
red.c: In function 'h':
red.c:15:1: error: unrecognizable insn:
   15 | }
      | ^
(insn 54 53 55 8 (set (reg:SI 192 [ g_lsm.9 ])
        (if_then_else:SI (ne:SI (reg:SI 136 [ _9 ])
                (const_int 0 [0]))
            (reg:SI 136 [ _9 ])
            (reg:SI 193))) -1
     (nil))
during RTL pass: vregs
red.c:15:1: internal compiler error: in extract_insn, at recog.cc:2812
0xa2a25d _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        ../../../gcc/gcc/rtl-error.cc:108
0xa2a27f _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        ../../../gcc/gcc/rtl-error.cc:116
0xa28b53 extract_insn(rtx_insn*)
        ../../../gcc/gcc/recog.cc:2812
0xedeaee instantiate_virtual_regs_in_insn
        ../../../gcc/gcc/function.cc:1611
0xedeaee instantiate_virtual_regs
        ../../../gcc/gcc/function.cc:1994
0xedeaee execute
        ../../../gcc/gcc/function.cc:2041
Please submit a full bug report, with preprocessed source.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
Preprocessed source stored into /scratch/tmp/ccFI5hsr.out file, please attach
this to your bugreport.

This testcase is a bit simpler since all the logic is in one function. It also
throws an ice with -O1 instead of -O3 that the previous testcase needed.