[Bug sanitizer/79589] New: ICE in gimplify_compound_expr (gimplify.c:5712) with -fsanitize=undefined

["marxin at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79589

            Bug ID: 79589
           Summary: ICE in gimplify_compound_expr (gimplify.c:5712) with
                    -fsanitize=undefined
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org,
                    mpolacek at gcc dot gnu.org
  Target Milestone: ---

Running trunk, following ICEs:

$ g++ /home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp1z/decomp18.C
-fsanitize=undefined -c -std=c++14

/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp1z/decomp18.C: In function
‘void foo()’:
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp1z/decomp18.C:10:15:
warning: decomposition declaration only available with -std=c++1z or
-std=gnu++1z
   for (auto & [ b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s ] : a) //
{ dg-warning "decomposition declaration only available with" "" { target
c++14_down } }
               ^
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp1z/decomp18.C:11:12:
internal compiler error: Segmentation fault
     z += b + c + d + e + f + g + h + i + j + k + l + m + n + o + p + q + r +
s;
          ~~^~~
0xb8b2af crash_signal
        ../../gcc/toplev.c:337
0x988e5a gimplify_compound_expr
        ../../gcc/gimplify.c:5712
0x985c97 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11181
0x98822a gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11312
0x985572 gimplify_compound_lval
        ../../gcc/gimplify.c:2844
0x985572 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11144
0x98563a gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11132
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920
0x985334 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc/gimplify.c:11920