[Bug tree-optimization/80842] New: gcc ICE at -O3 on x86_64-linux-gnu in "set_lattice_value"

[helloqirun at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80842

            Bug ID: 80842
           Summary: gcc ICE at -O3 on x86_64-linux-gnu in
                    "set_lattice_value"
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: helloqirun at gmail dot com
  Target Milestone: ---

The following code causes an ICE when compiled with the current gcc trunk at
-O3 on x86_64-linux-gnu in both 32- and 64-bit modes. 



$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/home/absozero/trunk/root-gcc/libexec/gcc/x86_64-pc-linux-gnu/8.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --prefix=/home/absozero/trunk/root-gcc
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 8.0.0 20170520 (experimental) [trunk revision 248308] (GCC)

$ gcc-trunk -O3 abc.c
abc.c: In function ‘fn3’:
abc.c:10:6: internal compiler error: in set_lattice_value, at
tree-ssa-ccp.c:505
 void fn3() {
      ^~~
0xc9efc8 set_lattice_value
        ../../gcc/gcc/tree-ssa-ccp.c:505
0xca3f2c visit_assignment
        ../../gcc/gcc/tree-ssa-ccp.c:2322
0xca40da ccp_visit_stmt
        ../../gcc/gcc/tree-ssa-ccp.c:2396
0xd2f518 simulate_stmt
        ../../gcc/gcc/tree-ssa-propagate.c:241
0xd30fb2 process_ssa_edge_worklist
        ../../gcc/gcc/tree-ssa-propagate.c:341
0xd30fb2 ssa_propagate(ssa_prop_result (*)(gimple*, edge_def**, tree_node**),
ssa_prop_result (*)(gphi*))
        ../../gcc/gcc/tree-ssa-propagate.c:813
0xc9de10 do_ssa_ccp
        ../../gcc/gcc/tree-ssa-ccp.c:2436
0xc9de10 execute
        ../../gcc/gcc/tree-ssa-ccp.c:2480
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.




$ cat abc.c
unsigned a;
short b;
char c, d, e;
void fn1();
void fn2() {
  a++;
  for (; a;)
    fn1(0, 0);
}
void fn3() {
  fn2();
l1:;
  unsigned char f;
  short g;
  unsigned char *h = &f;
  g += &h ? e ? g = 1 : 0 : 0;
  d = g;
  c *f;
  if (d & (b %= *h) < f * d / (d -= 0))
    goto l1;
}