[Bug tree-optimization/69209] New: ICE at -Os and above on x86_64-linux-gnu (verify_gimple failed)

["su at cs dot ucdavis.edu" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69209

            Bug ID: 69209
           Summary: ICE at -Os and above on x86_64-linux-gnu
                    (verify_gimple failed)
           Product: gcc
           Version: 6.0
            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: ---

The following code causes an ICE when compiled with the current gcc trunk at
-Os and above on x86_64-linux-gnu in both 32-bit and 64-bit modes.

It is a regression from 5.3.x. 

Possibly related to PR 69083, which has just been fixed. 


$ 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/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --prefix=/usr/local/gcc-trunk
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 6.0.0 20160108 (experimental) [trunk revision 232154] (GCC) 
$ 
$ gcc-trunk -O1 -c small.c
$ gcc-5.3 -Os -c small.c
$ 
$ gcc-trunk -Os -c small.c
small.c: In function âfn1â:
small.c:24:1: error: invalid operand in return statement
 }
 ^

f

# VUSE <.MEM_1(D)>
return f;
small.c:24:1: internal compiler error: verify_gimple failed
0xb30566 verify_gimple_in_cfg(function*, bool)
        ../../gcc-trunk/gcc/tree-cfg.c:5119
0xa24257 execute_function_todo
        ../../gcc-trunk/gcc/passes.c:1958
0xa24b4b execute_todo
        ../../gcc-trunk/gcc/passes.c:2010
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.
$ 


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int a, c, *d, e;

void __assert_fail () __attribute__ ((__noreturn__));

int
fn1 ()
{
  int f;
  if (a)
    {
      if (e)
        __assert_fail ();
      __assert_fail ();
    }
  d == &f ? (void) 0 : __assert_fail ();
  c ? (void) 0 : __assert_fail ();
  return f;
}

void
fn2 ()
{
  fn1 ();
}