[Bug tree-optimization/69740] [5/6 Regression] gcc ICE at -O2 and above on valid code on x86_64-linux-gnu in "verify_loop_structure"

["helloqirun at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69740

--- Comment #3 from Qirun Zhang <helloqirun at gmail dot com> ---
(In reply to Jakub Jelinek from comment #1)
> Started with r218566.

Here is a similar case. The stack trace is almost the same as in the original
RP's. However, this one crashes the current trunk at -O3 only (The original RP
still crashes the current trunk at -O2 and above).

I am not sure if this is a dup of the original RP..


$ 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/6.0.0/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 6.0.0 20160221 (experimental) [trunk revision 233594] (GCC)

$ gcc-trunk -O2 abc.c
$ gcc-trunk -Os abc.c
$ gcc-trunk -O3 abc.c
abc.c: In function 'main':
abc.c:7:5: error: loop with header 5 not in loop tree
 int main() {
     ^~~~
abc.c:7:5: internal compiler error: in verify_loop_structure, at cfgloop.c:1639
0x75e6bf verify_loop_structure()
        ../../gcc/gcc/cfgloop.c:1639
0x9d9e9e checking_verify_loop_structure
        ../../gcc/gcc/cfgloop.h:324
0x9d9e9e loop_optimizer_init(unsigned int)
        ../../gcc/gcc/loop-init.c:106
0xd198dd execute
        ../../gcc/gcc/tree-ssa-sink.c:619
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.


$ cat abc.c
inline int foo(int *p1, int p2) {
  int z = *p1;
  while (z > p2)
    p2 = 2;
  return z;
}
int main() {
  int i;
  for (;;) {
    int j, k;
    i = foo(&k, 7);
    if (k)
      j = i;
    else
      k = j;
    if (2 != j)
      __builtin_abort();
  }
}