tree-optimization/113895 - copy_reference_ops_from_ref vs. bitfields
The recent enhancement to discover constant array indices by range
info used by get_ref_base_and_extent doesn't work when the outermost
component reference is to a bitfield because we track the running
offset in the reference ops as bytes. The following does as
ao_ref_init_from_vn_reference and recovers that manually, tracking
the offset for the purpose of discovering the constant array index
in bits instead.
PR tree-optimization/113895
* tree-ssa-sccvn.cc (copy_reference_ops_from_ref): Track
offset to discover constant array indices in bits, handle
COMPONENT_REF to bitfields.