[Bug target/112681] New: [14 Regression] ICE: in extract_insn, at recog.cc:2804 (unrecognizable insn) with -O2 -mfma -mno-sse4.2 and memcmp()

[zsojka at seznam dot cz via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112681

            Bug ID: 112681
           Summary: [14 Regression] ICE: in extract_insn, at recog.cc:2804
                    (unrecognizable insn) with -O2 -mfma -mno-sse4.2 and
                    memcmp()
           Product: gcc
           Version: 14.0
            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: x86_64-pc-linux-gnu

Created attachment 56673
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56673&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc -O2 -mfma -mno-sse4.2 testcase.C 
testcase.C: In function 'int foo()':
testcase.C:11:1: error: unrecognizable insn:
   11 | }
      | ^
(insn 8 7 9 2 (set (reg:V16QI 104)
        (xor:V16QI (reg:V16QI 103)
            (mem/c:V16QI (reg/f:DI 102) [0 MEM <char[1:16]> [(void *)&b + 8B]+0
S16 A64]))) "testcase.C":10:27 -1
     (nil))
during RTL pass: vregs
testcase.C:11:1: internal compiler error: in extract_insn, at recog.cc:2804
0x8d9b93 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        /repo/gcc-trunk/gcc/rtl-error.cc:108
0x8d9c10 _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        /repo/gcc-trunk/gcc/rtl-error.cc:116
0x8c8a7f extract_insn(rtx_insn*)
        /repo/gcc-trunk/gcc/recog.cc:2804
0x14032bd instantiate_virtual_regs_in_insn
        /repo/gcc-trunk/gcc/function.cc:1610
0x14032bd instantiate_virtual_regs
        /repo/gcc-trunk/gcc/function.cc:1993
0x14032bd execute
        /repo/gcc-trunk/gcc/function.cc:2040
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.

$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r14-5779-20231123205631-g746344dd538-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--disable-bootstrap --with-cloog --with-ppl --with-isl
--build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu
--target=x86_64-pc-linux-gnu --with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r14-5779-20231123205631-g746344dd538-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.0.0 20231123 (experimental) (GCC)