[Bug tree-optimization/80901] New: ICE on valid code at -Os and above on x86_64-linux-gnu: in verify_loop_structure, at cfgloop.c:1644

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80901

            Bug ID: 80901
           Summary: ICE on valid code at -Os and above on
                    x86_64-linux-gnu: in verify_loop_structure, at
                    cfgloop.c:1644
           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: ---

$ 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 20170528 (experimental) [trunk revision 248544] (GCC) 
$ 
$ gcc-trunk -O1 small.c
$         
$ gcc-trunk -Os small.c
small.c: In function ‘fn1.part.0’:
small.c:24:1: error: size of loop 1 should be 1, not 2
 }
 ^
small.c:24:1: internal compiler error: in verify_loop_structure, at
cfgloop.c:1644
0x7da19d verify_loop_structure()
        ../../gcc-source-trunk/gcc/cfgloop.c:1644
0xb48b5f execute_function_todo
        ../../gcc-source-trunk/gcc/passes.c:1985
0xb495b9 execute_todo
        ../../gcc-source-trunk/gcc/passes.c:2023
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, d;

int fn1 ()
{
  int f;
  if (d)
    while (c)
      {
        for (f = 0; f < 1; f++)
          {
            int g[70] = { 0 };
            if (b)
              ;
            else
              {
                int h = !b;
                for (; h; h = 1)
                  ;
              }
          }
        return 0;
      }
  return a;
}

int main ()
{
  fn1 ();
  return 0;
}