re PR middle-end/22156 (bit-field copying regressed)

re PR middle-end/22156 (bit-field copying regressed)

PR middle-end/22156
Temporarily revert:
2007-04-06  Andreas Tobler  <a.tobler@schweiz.org>
2007-04-05  Alexandre Oliva  <aoliva@redhat.com>
* tree-sra.c (try_instantiate_multiple_fields): Needlessly
initialize align to silence bogus warning.
2007-04-05  Alexandre Oliva  <aoliva@redhat.com>
* tree-sra.c (struct sra_elt): Add in_bitfld_block.  Remove
all_no_warning.
(struct sra_walk_fns): Remove use_all parameter from use.
(sra_hash_tree): Handle BIT_FIELD_REFs.
(sra_elt_hash): Don't hash bitfld blocks.
(sra_elt_eq): Skip them in parent compares as well.  Handle
BIT_FIELD_REFs.
(sra_walk_expr): Don't maintain or pass down use_all_p.
(scan_use): Remove use_all parameter.
(scalarize_use): Likewise.  Re-expand assignment to
BIT_FIELD_REF of gimple_reg.  De-scalarize before input or
output, and re-scalarize after output.  Don't mark anything
for no warning.
(scalarize_ldst): Adjust.
(scalarize_walk_gimple_modify_statement): Likewise.
(build_element_name_1): Handle BIT_FIELD_REFs.
(instantiate_element): Don't warn for any element whose parent
is used as a whole.
(instantiate_missing_elements_1): Return the sra_elt.
(canon_type_for_field): New.
(try_instantiate_multiple_fields): New.
(instantiate_missing_elemnts): Use them.
(mark_no_warning): Removed.
(generate_one_element_ref): Handle BIT_FIELD_REFs.
(REPLDUP, sra_build_elt_assignment): New.
(generate_copy_inout): Use them.
(generate_element_copy): Likewise.  Handle bitfld differences.
(generate_element_zero): Don't recurse for blocks.  Use
sra_build_elt_assignment.
(generate_one_element_int): Take elt instead of var.  Use
sra_build_elt_assignment.
(generate_element_init_1): Adjust.
(scalarize_use, scalarize_copy): Use REPLDUP.
(scalarize_ldst): Move assert before dereference.
(dump_sra_elt_name): Handle BIT_FIELD_REFs.

From-SVN: r124302