[Bug middle-end/77383] -fcheck-pointer-bounds -mmpx ICE with VLA struct return type

[aivchenk at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77383

--- Comment #2 from Alexander Ivchenko <aivchenk at gmail dot com> ---
I debugged it and I suspect that the problem is in tree_function_versioning
(which is used for making instrumented clones of all functions in MPX).

Deep inside the logic of tree_function_versioning we do a copy of that
statement:
  *D.1824 = retframe_block (); [return slot optimization] 
:

(gdb) pgg orig_stmt
*D.1824 = retframe_block (); [return slot optimization]
(gdb) pct TYPE_SIZE(TREE_TYPE(gimple_call_lhs(orig_stmt)))
D.1820
(gdb) pct TYPE_SIZE(TREE_TYPE(gimple_call_fntype(orig_stmt)))
D.1820

And here is the copy of that gimple statement after remap_gimple_stmt 
(gdb) pgg stmt
MEM[(struct block *)D.1842] = retframe_block (); [return slot optimization]
(gdb) pct TYPE_SIZE(TREE_TYPE(gimple_call_lhs(stmt)))
D.1837
(gdb) pct TYPE_SIZE(TREE_TYPE(gimple_call_fntype(stmt)))
D.1820

where D.1820 is a local identifier from original "main" function
(gdb) pct get_containing_scope(TYPE_SIZE(TREE_TYPE(gimple_call_fntype(stmt))))
main
(gdb) pct get_containing_scope(TYPE_SIZE(TREE_TYPE(gimple_call_lhs(stmt))))
main.chkp

After later on MPX deletes bodies of original functions, expand crashes when
trying to make an rtl for D.1820 var_decl