[Bug rtl-optimization/114788] New: ICE on valid code at -O{2,3} on x86_64-linux-gnu (during RTL pass: sched2): in move_exprs_to_boundary, at sel-sched.cc:5236

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114788

            Bug ID: 114788
           Summary: ICE on valid code at -O{2,3} on x86_64-linux-gnu
                    (during RTL pass: sched2): in move_exprs_to_boundary,
                    at sel-sched.cc:5236
           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 is a regression from 12.*, and affects 13.* and later. 

Compiler Explorer: https://godbolt.org/z/n4MvPos5n

[679] % 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/14.0.1/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 14.0.1 20240420 (experimental) (GCC)
[680] %
[680] % gcctk -O3 -fno-guess-branch-probability -fselective-scheduling2
-fno-tree-sink -fschedule-insns -c small.c
during RTL pass: sched2
small.c: In function ‘main’:
small.c:32:1: internal compiler error: in move_exprs_to_boundary, at
sel-sched.cc:5236
   32 | }
      | ^
0x8424f2 move_exprs_to_boundary
        ../../gcc-trunk/gcc/sel-sched.cc:5236
0x8424f2 schedule_expr_on_boundary
        ../../gcc-trunk/gcc/sel-sched.cc:5444
0x1125588 fill_insns
        ../../gcc-trunk/gcc/sel-sched.cc:5586
0x1125588 schedule_on_fences
        ../../gcc-trunk/gcc/sel-sched.cc:7361
0x1125588 sel_sched_region_2
        ../../gcc-trunk/gcc/sel-sched.cc:7499
0x1126c78 sel_sched_region_1
        ../../gcc-trunk/gcc/sel-sched.cc:7541
0x1128a19 sel_sched_region(int)
        ../../gcc-trunk/gcc/sel-sched.cc:7642
0x1128a19 sel_sched_region(int)
        ../../gcc-trunk/gcc/sel-sched.cc:7627
0x1129a21 run_selective_scheduling()
        ../../gcc-trunk/gcc/sel-sched.cc:7728
0x1106c0d rest_of_handle_sched2
        ../../gcc-trunk/gcc/sched-rgn.cc:3741
0x1106c0d execute
        ../../gcc-trunk/gcc/sched-rgn.cc:3888
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.
[681] % cat small.c
extern void r();
int b, d, g, l;
char c, e, f;
volatile char h;
int main() {
  int k, i, m, q;
  for (; b && i; i++) {
    int n = k;
  L1:
    k = 0 || d;
    while (n < e)
      ;
  }
  b = f;
 L2:
  if (h)
    r();
  if (l) {
    int a, j = f / g, o = (j / c && f) % d, p = (f % q * ~h && c && j) / k;
    if (h) {
      a = d;
      p = m;
      k = k / l / (2 * f % 3);
      m = o & c / ((m && a) ^ (p && 2 / g) | f);
      if (m)
        goto L1;
    }
    m = p;
    goto L2;
  }
  return 0;
}