[Bug target/109508] New: [13 Regression] ICE: in extract_insn, at recog.cc:2791 with -mcpu=sifive-s76 on riscv64

["zsojka at seznam dot cz" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109508

            Bug ID: 109508
           Summary: [13 Regression] ICE: in extract_insn, at recog.cc:2791
                    with -mcpu=sifive-s76 on riscv64
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: riscv64-unknown-linux-gnu

Created attachment 54855
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54855&action=edit
reduced testcase

Compiler output:
$ riscv64-unknown-linux-gnu-gcc -mcpu=sifive-s76 testcase.c
testcase.c: In function 'foo':
testcase.c:9:1: error: unrecognizable insn:
    9 | }
      | ^
(insn 16 15 17 2 (set (reg:DI 146)
        (if_then_else:DI (ne:DI (reg:DI 147)
                (const_int 0 [0]))
            (const_int 0 [0])
            (const_int 6 [0x6]))) -1
     (nil))
during RTL pass: vregs
testcase.c:9:1: internal compiler error: in extract_insn, at recog.cc:2791
0x7a1b18 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        /repo/gcc-trunk/gcc/rtl-error.cc:108
0x7a1b94 _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        /repo/gcc-trunk/gcc/rtl-error.cc:116
0x7932ca extract_insn(rtx_insn*)
        /repo/gcc-trunk/gcc/recog.cc:2791
0xd1ae6f instantiate_virtual_regs_in_insn
        /repo/gcc-trunk/gcc/function.cc:1611
0xd1ae6f instantiate_virtual_regs
        /repo/gcc-trunk/gcc/function.cc:1985
0xd1ae6f execute
        /repo/gcc-trunk/gcc/function.cc:2034
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

$ riscv64-unknown-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-riscv64/bin/riscv64-unknown-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r13-7168-20230413170248-ga1afdc6e2aa-checking-yes-rtl-df-extra-riscv64/bin/../libexec/gcc/riscv64-unknown-linux-gnu/13.0.1/lto-wrapper
Target: riscv64-unknown-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--with-cloog --with-ppl --with-isl --with-isa-spec=2.2
--with-sysroot=/usr/riscv64-unknown-linux-gnu --build=x86_64-pc-linux-gnu
--host=x86_64-pc-linux-gnu --target=riscv64-unknown-linux-gnu
--with-ld=/usr/bin/riscv64-unknown-linux-gnu-ld
--with-as=/usr/bin/riscv64-unknown-linux-gnu-as --disable-multilib
--disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r13-7168-20230413170248-ga1afdc6e2aa-checking-yes-rtl-df-extra-riscv64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.0.1 20230413 (experimental) (GCC)