[Bug tree-optimization/115226] New: ICE on valid code at -O3 on x86_64-linux-gnu: verify_ssa failed

["zhendong.su at inf dot ethz.ch" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115226

            Bug ID: 115226
           Summary: ICE on valid code at -O3 on x86_64-linux-gnu:
                    verify_ssa failed
           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/EK1hn9n4s


[538] % 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 20240525 (experimental) (GCC) 
[539] % 
[539] % gcctk -O3 small.c 
small.c: In function ‘main’:
small.c:3:5: error: stmt with wrong VUSE
    3 | int main() {
      |     ^~~~
# .MEM_4 = VDEF <.MEM_15>
a = 0;
expected .MEM_2
during GIMPLE pass: unswitch
small.c:3:5: internal compiler error: verify_ssa failed
0x140b2be verify_ssa(bool, bool)
        ../../gcc-trunk/gcc/tree-ssa.cc:1203
0x102deb5 execute_function_todo
        ../../gcc-trunk/gcc/passes.cc:2096
0x102e71e execute_todo
        ../../gcc-trunk/gcc/passes.cc:2143
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.
[540] % 
[540] % cat small.c
extern void c();
int a, b;
int main() {
  while (b) {
    int d, e = 0, *f = &a;
    *f = 1;
    e = 1 >> d ? : 1 << d;
    if (e)
      a = 0;
    c();
  }
  return 0;
}