[Bug tree-optimization/103268] New: [12 regression] ICE om glib-2.10.1: internal compiler error: in optimize_atomic_bit_test_and, at tree-ssa-ccp.c:3626

["slyfox at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103268

            Bug ID: 103268
           Summary: [12 regression] ICE om glib-2.10.1: internal compiler
                    error: in optimize_atomic_bit_test_and, at
                    tree-ssa-ccp.c:3626
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at gcc dot gnu.org
  Target Milestone: ---

ICE is initially observed on glib-2.70.1. Here is extracted example:

    // $ cat a.c.c
    void g_assertion_message_cmpnum(long);

    static int si;

    void test_types(long n) {
       unsigned u2 = ({ __atomic_fetch_xor(&si, 0, 5); });
      long l = u2;
      g_assertion_message_cmpnum(l);
    }

$ gcc-12.0.0 a.c.c -c -O2
a.c.c: In function 'test_types':
a.c.c:5:22: warning: unused parameter 'n' [-Wunused-parameter]
    5 | void test_types(long n) {
      |                 ~~~~~^
during GIMPLE pass: fab
a.c.c:5:6: internal compiler error: in optimize_atomic_bit_test_and, at
tree-ssa-ccp.c:3626
    5 | void test_types(long n) {
      |      ^~~~~~~~~~
0x1df4a67 internal_error(char const*, ...)
        ???:0
0x8d493d fancy_abort(char const*, int, char const*)
        ???:0
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

$ gcc-12.0.0 -v
Using built-in specs.
COLLECT_GCC=/nix/store/kb1by7nzcqlv8j2hl7q0kks8fw8dpym0-gcc-12.0.0/bin/gcc
COLLECT_LTO_WRAPPER=/nix/store/kb1by7nzcqlv8j2hl7q0kks8fw8dpym0-gcc-12.0.0/libexec/gcc/x86_64-unknown-linux-gnu/12.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with:
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20211114 (experimental) (GCC)