[Bug tree-optimization/118464] [15 Regression] gcc-15.0.0_pre20250112 ICE with opencv-4.10.0 using -O2/-ftree-loop-vectorize: memory_descriptor_ref.cpp:94:19: internal compiler error: in exact_div, at poly-int.h:2160 since r15-6807-g68326d5d1a593d

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118464

Zhendong Su <zhendong.su at inf dot ethz.ch> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |zhendong.su at inf dot ethz.ch

--- Comment #9 from Zhendong Su <zhendong.su at inf dot ethz.ch> ---
Another reproducer:

[568] % 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/15.0.1/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 15.0.1 20250114 (experimental) (GCC)
[569] %
[569] % gcctk -O3 small.c
during GIMPLE pass: vect
small.c: In function ‘main’:
small.c:3:5: internal compiler error: in exact_div, at poly-int.h:2160
    3 | int main() {
      |     ^~~~
0x26cf206 internal_error(char const*, ...)
        ../../gcc-trunk/gcc/diagnostic-global-context.cc:517
0xac1806 fancy_abort(char const*, int, char const*)
        ../../gcc-trunk/gcc/diagnostic.cc:1722
0xabbac6 poly_int<1u, poly_result<unsigned long, if_nonpoly<unsigned long,
unsigned long, poly_int_traits<unsigned long>::is_poly>::type,
poly_coeff_pair_traits<unsigned long, if_nonpoly<unsigned long, unsigned long,
poly_int_traits<unsigned long>::is_poly>::type>::result_kind>::type>
exact_div<1u, unsigned long, unsigned long>(poly_int<1u, unsigned long> const&,
unsigned long)
        ../../gcc-trunk/gcc/poly-int.h:2160
0xabbac6 poly_int<1u, poly_result<unsigned long, unsigned long,
poly_coeff_pair_traits<unsigned long, unsigned long>::result_kind>::type>
exact_div<1u, unsigned long, unsigned long>(poly_int<1u, unsigned long> const&,
poly_int<1u, unsigned long> const&)
        ../../gcc-trunk/gcc/poly-int.h:2173
0xabbac6 vect_get_num_vectors(poly_int<1u, unsigned long>, tree_node*)
        ../../gcc-trunk/gcc/tree-vectorizer.h:2118
0xabbac6 vect_compute_data_ref_alignment
        ../../gcc-trunk/gcc/tree-vect-data-refs.cc:1388
0x25e45fa vect_analyze_data_refs_alignment(_loop_vec_info*)
        ../../gcc-trunk/gcc/tree-vect-data-refs.cc:2946
0x1562aa1 vect_analyze_loop_2
        ../../gcc-trunk/gcc/tree-vect-loop.cc:2959
0x15648f5 vect_analyze_loop_1
        ../../gcc-trunk/gcc/tree-vect-loop.cc:3480
0x15650d0 vect_analyze_loop(loop*, gimple*, vec_info_shared*)
        ../../gcc-trunk/gcc/tree-vect-loop.cc:3640
0x15b4392 try_vectorize_loop_1
        ../../gcc-trunk/gcc/tree-vectorizer.cc:1094
0x15b4392 try_vectorize_loop
        ../../gcc-trunk/gcc/tree-vectorizer.cc:1210
0x15b4c8c execute
        ../../gcc-trunk/gcc/tree-vectorizer.cc:1326
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.
[570] %
[570] % cat small.c
int a, b, c, d, e, f;
short g[1];
int main() {
  int h;
  while (a) {
    while (h)
      ;
    for (b = 2; b; b--) {
      while (c)
        ;
      f = g[a];
      if (d)
        break;
    }
    while (e)
      ;
  }
  return 0;
}