[Bug c++/83166] New: [8 regression] error: type mismatch in pointer diff expression internal compiler error: verify_gimple failed

[skpgkp1 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83166

            Bug ID: 83166
           Summary: [8 regression] error: type mismatch in pointer diff
                    expression internal compiler error: verify_gimple
                    failed
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: skpgkp1 at gmail dot com
  Target Milestone: ---

This issue appear in dmtcp build with GCC 8.0. GCC 7.2.1 works fine.

$ cat mtcp_restart.i.c
char a;
b() { long c = (char *)b - &a; }

### Fail with GCC 8.0

$gcc --version
gcc (GCC) 8.0.0 20171124 (experimental)
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$gcc -g -O2 -c  -o mtcp_restart.i.c.o -fPIC -fno-stack-protector -g -O0
mtcp_restart.i.c
mtcp_restart.i.c:2:1: warning: return type defaults to ‘int’ [-Wimplicit-int]
 b() { long c = (char *)b - &a; }
 ^
mtcp_restart.i.c: In function ‘b’:
mtcp_restart.i.c:2:1: error: type mismatch in pointer diff expression
long int

int (*<T2f9>) ()

char *

c = b - &a;
mtcp_restart.i.c:2:1: internal compiler error: verify_gimple failed
0xd4a52d verify_gimple_in_seq(gimple*)
        ../../gcc-main.3O1G/gcc/tree-cfg.c:5094
0xb00bdd gimplify_body(tree_node*, bool)
        ../../gcc-main.3O1G/gcc/gimplify.c:12606
0xb00dc4 gimplify_function_tree(tree_node*)
        ../../gcc-main.3O1G/gcc/gimplify.c:12696
0x998d47 cgraph_node::analyze()
        ../../gcc-main.3O1G/gcc/cgraphunit.c:670
0x99b835 analyze_functions
        ../../gcc-main.3O1G/gcc/cgraphunit.c:1131
0x99c412 symbol_table::finalize_compilation_unit()
        ../../gcc-main.3O1G/gcc/cgraphunit.c:2690
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.

### Pass with GCC 7.2.1

$gcc --version
gcc (GCC) 7.2.1 20171124
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$gcc -g -O2 -c  -o mtcp_restart.i.c.o -fPIC -fno-stack-protector -g -O0
mtcp_restart.i.c
mtcp_restart.i.c:2:1: warning: return type defaults to ‘int’ [-Wimplicit-int]
 b() { long c = (char *)b - &a; }
 ^
$ echo $?
0