[Bug tree-optimization/112636] New: ICE on valid code at -O1 (but not at -O{0,s,2,3}) with "-ftree-vectorize": in adjust_loop_info_after_peeling, at tree-ssa-loop-ivcanon.cc:1069

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112636

            Bug ID: 112636
           Summary: ICE on valid code at -O1 (but not at -O{0,s,2,3}) with
                    "-ftree-vectorize": in adjust_loop_info_after_peeling,
                    at tree-ssa-loop-ivcanon.cc:1069
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

This appears to be a recent regression as it does not seem to reproduce with
13.2.

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

[526] % 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/14.0.0/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 14.0.0 20231119 (experimental) (GCC) 
[527] % 
[527] % gcctk -O1 small.c; ./a.out
[528] % 
[528] % gcctk -O1 -ftree-vectorize small.c
during GIMPLE pass: ch_vect
small.c: In function ‘main’:
small.c:3:5: internal compiler error: in adjust_loop_info_after_peeling, at
tree-ssa-loop-ivcanon.cc:1069
    3 | int main() {
      |     ^~~~
0x87ac95 adjust_loop_info_after_peeling(loop*, int, bool)
        ../../gcc-trunk/gcc/tree-ssa-loop-ivcanon.cc:1069
0x129b514 copy_headers
        ../../gcc-trunk/gcc/tree-ssa-loop-ch.cc:1108
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.
[529] % 
[529] % cat small.c
int a[1], b;
unsigned c;
int main() {
  while (b) {
    if (a[c])
      break;
    c--;
  }
  return 0;
}