[Bug tree-optimization/78607] New: [7 Regression] ICE: verify_flow_info failed (error: missing barrier after block 2)

["asolokha at gmx dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78607

            Bug ID: 78607
           Summary: [7 Regression] ICE: verify_flow_info failed (error:
                    missing barrier after block 2)
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---
            Target: powerpc-*-linux-gnu*

gcc-7.0.0-alpha20161127 snapshot (r242902) w/ stand-alone r242947 applied on
top of it ICEs when compiling the following snippets for 32-bit BE powerpc w/
-O2 or above:

% cat ffjloyn2.c 
void
rc (int cx)
{
  int mq;

  if (mq == 0 && (cx / 0) != 0)
    for (;;)
      {
      }
}
% powerpc-e300c3-linux-gnu-gcc-7.0.0-alpha20161127 -O2 -w -c ffjloyn2.c
ffjloyn2.c: In function 'rc':
ffjloyn2.c:10:1: error: missing barrier after block 2
 }
 ^
ffjloyn2.c:10:1: internal compiler error: verify_flow_info failed
0x30be2f3d1a1 verify_flow_info()
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-7.0.0_alpha20161127/work/gcc-7-20161127/gcc/cfghooks.c:260
0x30be2f57c91 execute
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-7.0.0_alpha20161127/work/gcc-7-20161127/gcc/cfgrtl.c:3569

% cat lvh5rgvk.c
void
xt (void)
{
  int pk, op;

  for (;;)
    if (pk >= op)
      op /= 0;
}
% powerpc-e300c3-linux-gnu-gcc-7.0.0-alpha20161127 -O2 -w -c lvh5rgvk.c
lvh5rgvk.c: In function 'xt':
lvh5rgvk.c:9:1: error: missing barrier after block 2
 }
 ^
lvh5rgvk.c:9:1: internal compiler error: verify_flow_info failed
0x2b5475d11a1 verify_flow_info()
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-7.0.0_alpha20161127/work/gcc-7-20161127/gcc/cfghooks.c:260
0x2b5475ebc91 execute
       
/var/tmp/portage/cross-powerpc-e300c3-linux-gnu/gcc-7.0.0_alpha20161127/work/gcc-7-20161127/gcc/cfgrtl.c:3569