[Bug tree-optimization/115236] New: wrong code at -O1 and above with -fno-tree-fre on x86_64-linux-gnu

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115236

            Bug ID: 115236
           Summary: wrong code at -O1 and above with -fno-tree-fre on
                    x86_64-linux-gnu
           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: ---

It appears to be a recent regression as it doesn't reproduce with 14.1 and
earlier. 

Compiler Explorer: https://godbolt.org/z/xhY65cevr

[533] % 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 20240526 (experimental) (GCC) 
[534] % 
[534] % gcctk -O1 small.c; ./a.out
[535] % 
[535] % gcctk -O1 -fno-tree-fre small.c
[536] % ./a.out
Aborted
[537] % cat small.c
int a, *b = &a;
int main() {
  int *c, *volatile *d = &c;
  *d = b;
  if (c != &a)
    __builtin_abort();
  return 0;
}