[Bug tree-optimization/70190] New: ICE (segfault) at -O2 and -O3 on x86_64-linux-gnu

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70190

            Bug ID: 70190
           Summary: ICE (segfault) at -O2 and -O3 on x86_64-linux-gnu
           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 on
x86_64-linux-gnu at -O2 and -O3 in both 32-bit and 64-bit modes.

This is a regression from 5.3.x.


$ 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-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/usr/local/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 6.0.0 20160311 (experimental) [trunk revision 234134] (GCC) 
$ 
$ gcc-trunk -Os -c small.c
$ gcc-5.3 -O2 -c small.c
$ 
$ gcc-trunk -O2 -c small.c
small.c: In function ‘fn1’:
small.c:2:1: internal compiler error: Segmentation fault
 fn1 ()
 ^~~
0xb6627f crash_signal
        ../../gcc-source-trunk/gcc/toplev.c:335
0x12f6e42 fsm_find_control_statement_thread_paths
        ../../gcc-source-trunk/gcc/tree-ssa-threadbackward.c:390
0x12f75c2 find_jump_threads_backwards(edge_def*)
        ../../gcc-source-trunk/gcc/tree-ssa-threadbackward.c:544
0xd5acf5 thread_across_edge(gcond*, edge_def*, bool, const_and_copies*,
avail_exprs_stack*, tree_node* (*)(gimple*, gimple*, avail_exprs_stack*))
        ../../gcc-source-trunk/gcc/tree-ssa-threadedge.c:1027
0xc8cbf0 dom_opt_dom_walker::thread_across_edge(edge_def*)
        ../../gcc-source-trunk/gcc/tree-ssa-dom.c:989
0xc8cde9 dom_opt_dom_walker::after_dom_children(basic_block_def*)
        ../../gcc-source-trunk/gcc/tree-ssa-dom.c:1408
0x1221407 dom_walker::walk(basic_block_def*)
        ../../gcc-source-trunk/gcc/domwalk.c:307
0xc8f78b execute
        ../../gcc-source-trunk/gcc/tree-ssa-dom.c:614
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.
$ 


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


int
fn1 ()
{
  static char a[] = "foo";
  static void *b[] = { &&l1, &&l2 };
  goto *(b[1]);
 l1: goto *(a[0]);
 l2: return 0;
}