[Bug c/78510] New: ice on invalid C code at -O2 and above in both 32-bit and 64-bit modes on x86_64-linux-gnu (internal compiler error: verify_gimple failed)

[chengniansun at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78510

            Bug ID: 78510
           Summary: ice on invalid C code at -O2 and above in both 32-bit
                    and 64-bit modes on x86_64-linux-gnu (internal
                    compiler error: verify_gimple failed)
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: chengniansun at gmail dot com
  Target Milestone: ---

$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/usr/local/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 7.0.0 20161124 (experimental) [trunk revision 242818] (GCC)
$
$ gcc-trunk -O3 small.c
small.c: In function ‘main’:
small.c:17:5: error: type mismatch in conditional expression
 int main() { fn2(); return 0; }
     ^~~~
short int
int
short int
iftmp.1_11 = _6 == 4 ? 4 : 0;
small.c:17:5: internal compiler error: verify_gimple failed
0xc317f6 verify_gimple_in_cfg(function*, bool)
        ../../gcc-source-trunk/gcc/tree-cfg.c:5258
0xb0f84a execute_function_todo
        ../../gcc-source-trunk/gcc/passes.c:1965
0xb10285 execute_todo
        ../../gcc-source-trunk/gcc/passes.c:2015
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
$
$ cat small.c
int a, b, c, e, f;
char d;
short g, h;
char fn1(int p1) {
  for (;;) {
    h = p1 << 2;
    int i = h;
    g = i > 32767 >> 13 ? i : i << 3;
    f = a ?: c;
    if (e)
      return d;
  }
}

static int fn2() { fn1(0 || b); }

int main() { fn2(); return 0; }