[Bug tree-optimization/87263] New: ICE on valid code at -O1: verify_ssa failed

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87263

            Bug ID: 87263
           Summary: ICE on valid code at -O1: verify_ssa failed
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

It appears to be a recent regression. 

$ gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/home/su/software/tmp/gcc/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/9.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/home/su/software/tmp/gcc/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 9.0.0 20180909 (experimental) [trunk revision 264184] (GCC)
$
$ gcctk -O0 small.c
$
$ gcctk -O1 small.c
small.c: In function ‘main’:
small.c:22:1: error: definition in block 5 does not dominate use in block 6
22 | }
   | ^
for SSA_NAME: k_16 in statement:
_6 = c.3_5 > k_16;
during GIMPLE pass: fre
small.c:22:1: internal compiler error: verify_ssa failed
0xfd4163 verify_ssa(bool, bool)
        ../../gcc-source-trunk/gcc/tree-ssa.c:1188
0xc8bb43 execute_function_todo
        ../../gcc-source-trunk/gcc/passes.c:1950
0xc8c469 execute_todo
        ../../gcc-source-trunk/gcc/passes.c:1997
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.
$

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

int a, b, c;

int main ()
{ 
  int g, *h[3] = {&g, &g, &g};
  if (h[2] == 0)
    ;
  else
    { 
      int i[1];
      if (a)
        while (a)
        L:;
      else
        { 
          int k = b;
        }
    }
  if ((b < c) > b)
    goto L;
  return 0;
}