[Bug rtl-optimization/114942] New: ICE on valid code at -O1 with "-fno-tree-sra -fno-guess-branch-probability": in extract_constrain_insn, at recog.cc:2713

[zhendong.su at inf dot ethz.ch via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114942

            Bug ID: 114942
           Summary: ICE on valid code at -O1 with "-fno-tree-sra
                    -fno-guess-branch-probability": in
                    extract_constrain_insn, at recog.cc:2713
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

It appears to be a recent regression as it doesn't reproduce with 13.2 and
earlier.

Compiler Explorer: https://godbolt.org/z/av9hr4933

[648] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/15.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--enable-checking=yes --prefix=/local/suz-local/software/local/gcc-trunk
--enable-sanitizers --enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 15.0.0 20240503 (experimental) (GCC)
[649] %
[649] % gcctk -O1 -c -fno-tree-sra -fno-guess-branch-probability small.c
small.c: In function ‘main’:
small.c:21:1: error: insn does not satisfy its constraints:
   21 | }
      | ^
(insn 39 56 57 6 (parallel [
            (set (strict_low_part (reg:QI 2 cx [orig:108 f ] [108]))
                (ior:QI (subreg:QI (zero_extract:HI (reg/v:HI 2 cx [orig:108 f
] [108])
                            (const_int 8 [0x8])
                            (const_int 8 [0x8])) 0)
                    (reg:QI 0 ax [orig:121 _7 ] [121])))
            (clobber (reg:CC 17 flags))
        ]) "small.c":19:7 626 {*iorqi_exthi_1_slp}
     (nil))
during RTL pass: reload
small.c:21:1: internal compiler error: in extract_constrain_insn, at
recog.cc:2713
0x83dea6 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        ../../gcc-trunk/gcc/rtl-error.cc:108
0x83ded2 _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        ../../gcc-trunk/gcc/rtl-error.cc:118
0x83c10c extract_constrain_insn(rtx_insn*)
        ../../gcc-trunk/gcc/recog.cc:2713
0xf55a67 check_rtl
        ../../gcc-trunk/gcc/lra.cc:2189
0xf5aef1 lra(_IO_FILE*, int)
        ../../gcc-trunk/gcc/lra.cc:2610
0xf0b1ff do_reload
        ../../gcc-trunk/gcc/ira.cc:5973
0xf0b1ff execute
        ../../gcc-trunk/gcc/ira.cc:6161
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.
[650] %
[650] % cat small.c
extern void a();
struct b {
  char c;
  char d;
} e;
int main() {
  struct b f = e;
  char i = 0;
 L1:
  if (!f.c)
    goto L2;
  if (e.c)
    a();
  else
    return 0;
  f.d = 0;
  i = 1 % ((1 & f.c) - 2);
 L2:
  f.c = ~(i & ~f.d);
  goto L1;
}