[Bug rtl-optimization/115929] New: ICE on valid code at -O{2, 3} with "-fschedule-insns" on x86_64-linux-gnu: Segmentation fault

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115929

            Bug ID: 115929
           Summary: ICE on valid code at -O{2,3} with "-fschedule-insns"
                    on x86_64-linux-gnu: Segmentation fault
           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 14.1 and
earlier. 

Compiler Explorer: https://godbolt.org/z/eaE7z3ser

[536] % 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 20240714 (experimental) (GCC) 
[537] % 
[537] % gcctk -O2 -fschedule-insns small.c
during RTL pass: late_combine
small.c: In function ‘main’:
small.c:20:1: internal compiler error: Segmentation fault
   20 | }
      | ^
0x24979f5 internal_error(char const*, ...)
        ../../gcc-trunk/gcc/diagnostic-global-context.cc:491
0x1190963 crash_signal
        ../../gcc-trunk/gcc/toplev.cc:319
0x7f26ce20a08f ???
       
/build/glibc-LcI20x/glibc-2.31/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
0x2337afe rtl_ssa::insn_info::is_bb_head() const
        ../../gcc-trunk/gcc/rtl-ssa/member-fns.inl:610
0x2337afe rtl_ssa::can_insert_after(rtl_ssa::insn_info*)
        ../../gcc-trunk/gcc/rtl-ssa/movement.h:68
0x2337afe rtl_ssa::canonicalize_move_range(rtl_ssa::insn_range_info&,
rtl_ssa::insn_info*)
        ../../gcc-trunk/gcc/rtl-ssa/movement.h:78
0x2337afe restrict_movement_for_dead_range<(anonymous
namespace)::insn_combination::substitute_nondebug_use(rtl_ssa::use_info*)::local_ignore>
        ../../gcc-trunk/gcc/rtl-ssa/movement.h:163
0x2337afe add_regno_clobber<(anonymous
namespace)::insn_combination::substitute_nondebug_use(rtl_ssa::use_info*)::local_ignore>
        ../../gcc-trunk/gcc/rtl-ssa/member-fns.inl:982
0x2337afe operator()
        ../../gcc-trunk/gcc/rtl-ssa/change-utils.h:105
0x2337afe _M_invoke
        /usr/include/c++/9/bits/std_function.h:285
0x2390667 std::function<bool (rtl_ssa::insn_change&, unsigned
int)>::operator()(rtl_ssa::insn_change&, unsigned int) const
        /usr/include/c++/9/bits/std_function.h:688
0x2390667 add_clobber
        ../../gcc-trunk/gcc/rtl-ssa/changes.cc:934
0x2390667 recog_level2
        ../../gcc-trunk/gcc/rtl-ssa/changes.cc:1027
0x2391be8 rtl_ssa::recog_internal(rtl_ssa::insn_change&, std::function<bool
(rtl_ssa::insn_change&, unsigned int)>)
        ../../gcc-trunk/gcc/rtl-ssa/changes.cc:1131
0x23389e9 recog<(anonymous
namespace)::insn_combination::substitute_nondebug_use(rtl_ssa::use_info*)::local_ignore>
        ../../gcc-trunk/gcc/rtl-ssa/change-utils.h:107
0x23389e9 substitute_nondebug_use
        ../../gcc-trunk/gcc/late-combine.cc:256
0x23389e9 substitute_nondebug_uses
        ../../gcc-trunk/gcc/late-combine.cc:270
0x23395c5 run
        ../../gcc-trunk/gcc/late-combine.cc:439
0x23395c5 combine_into_uses
        ../../gcc-trunk/gcc/late-combine.cc:683
0x2339db7 execute
        ../../gcc-trunk/gcc/late-combine.cc:711
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.
[538] % 
[538] % cat small.c
int a, b, c, d, e, f;
int main() {
  if (e && f)
    while (1)
      while (a)
        a = 0;
  if (c) {
    if (b)
      goto g;
    int h = a;
  i:
    b = ~((b ^ h) | 1 % b);
    if (a)
    g:
      b = 0;
  }
  if (d)
    goto i;
  return 0;
}