We fail to verify the constraints under which we allow handled
components to wrap registers. The gcc.dg/pr70022.c testcase shows
that we happily end up with
_2 = VIEW_CONVERT_EXPR<int[4]>(v_1(D))
as produced by SSA rewrite and update_address_taken. But the intent
was that we wrap registers with at most a single level of handled
components and specifically only allow __real, __imag, BIT_FIELD_REF
and VIEW_CONVERT_EXPR on them, but not ARRAY_REF or COMPONENT_REF.
The following makes IL verification stricter which catches the
problem.
PR tree-optimization/109644
* tree-cfg.cc (verify_types_in_gimple_reference): Check
register constraints on the outermost VIEW_CONVERT_EXPR
only. Do not allow register or invariant bases on
multi-level or possibly variable index handled components.