[Bug tree-optimization/71407] New: ICE at -O3 in 32-bit and 64-bit modes on x86_64-linux-gnu (verify_gimple: integral result type precision does not match field size of BIT_FIELD_REF)

["chengniansun at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71407

            Bug ID: 71407
           Summary: ICE at -O3 in 32-bit and 64-bit modes on
                    x86_64-linux-gnu (verify_gimple: integral result type
                    precision does not match field size of BIT_FIELD_REF)
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          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 20160603 (experimental) [trunk revision 237082] (GCC) 
$: 
$: gcc-trunk -O3 small.c -w
small.c: In function âfn2â:
small.c:6:6: error: integral result type precision does not match field size of
BIT_FIELD_REF
 void fn2() {
      ^~~
BIT_FIELD_REF <mask__22.25_75, 8, 120>
cc1: note: in statement
_70 = BIT_FIELD_REF <mask__22.25_75, 8, 120>;
small.c:6:6: internal compiler error: verify_gimple failed
0xbf0a26 verify_gimple_in_cfg(function*, bool)
        ../../gcc-source-trunk/gcc/tree-cfg.c:5211
0xaddd7a execute_function_todo
        ../../gcc-source-trunk/gcc/passes.c:1964
0xade7fb execute_todo
        ../../gcc-source-trunk/gcc/passes.c:2016
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, d;
char b;
short c;
short fn1() {}

void fn2() {
  int e;
  for (; c; c++) {
    for (; a; a++)
      b = fn1() || e;
    e = d;
  }
}

int main() {}
$: