[Bug middle-end/81030] New: ICE on valid code at -O1 (only) on x86_64-linux-gnu: verify_flow_info failed

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81030

            Bug ID: 81030
           Summary: ICE on valid code at -O1 (only) on x86_64-linux-gnu:
                    verify_flow_info failed
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

This is a recent regression. 

$ 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/8.0.0/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 8.0.0 20170609 (experimental) [trunk revision 249045] (GCC)
$
$ gcc-trunk -O0 small.c
$
$ gcc-trunk -O1 small.c
small.c: In function ‘main’:
small.c:26:1: error: verify_flow_info: REG_BR_PROB does not match cfg 3663 7327
 }
 ^
during RTL pass: expand
small.c:26:1: internal compiler error: verify_flow_info failed
0x7d9956 verify_flow_info()
        ../../gcc-source-trunk/gcc/cfghooks.c:259
0x1323c20 checking_verify_flow_info
        ../../gcc-source-trunk/gcc/cfghooks.h:198
0x1323c20 try_optimize_cfg
        ../../gcc-source-trunk/gcc/cfgcleanup.c:3039
0x1323c20 cleanup_cfg(int)
        ../../gcc-source-trunk/gcc/cfgcleanup.c:3203
0x7d6566 execute
        ../../gcc-source-trunk/gcc/cfgexpand.c:6485
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.
$


----------------------------------------------------------------------------


void __assert_fail (const char *, const char *, unsigned int, const char *);

int a, b, c, d, e, f, h;
unsigned char g;

int main ()
{ 
  int i, *j = &b;
  if (a)
    { 
      if (h)
        { 
          int **k = &j;
          d = 0;
          *k = &e;
        }
      else
        for (b = 0; b > -28; b = g)
          ;
      c || !j ? : __assert_fail ("c || !j", "small.c", 20, "main");
      if (f)
        for (i = 0; i < 1; i++)
          ;
    }
  return 0;
}