PATCH RFC: Use type alias_set_type to hold alias sets

[Ian Lance Taylor <iant at google dot com>]

In this patch:
    http://gcc.gnu.org/ml/gcc-patches/2000-05/msg01680.html
Richard Kenner changed the type of alias sets from int to
HOST_WIDE_INT.  However, the change was not made consistently.  There
are a number of places in the compiler which store alias sets in a
simple int; e.g., the static variable alpha_sr_alias_set in alpha.c.

According to his e-mail message, the change was made to permit
frontends to use a sparse definition of alias sets.  However, no
frontend takes advantage of that facility, and I am doubtful that any
frontend ever would.  Since alias sets are allocated directly by the
middle-end, as well as by the frontend via LANG_HOOKS_GET_ALIAS_SET,
it is hard to see how a frontend could be sure to avoid alias sets
allocated by the middle-end.

The code in dse.c stores alias set numbers in bitmaps, which is only
supported for int, not for HOST_WIDE_INT.  This code is admittedly
rather new.

So there is no reason to use HOST_WIDE_INT for alias sets, it never
fully worked, and it works even less well now.  I think it is time to
change alias sets back to have type int, which should save a bit of
space in DECLs and MEM_ATTRs.

To avoid the kind of error made in the original patch, in which some
variables did not change type, this is a purely mechanical patch to
change all alias set representations to have type alias_set_type.
This does not change the compiler, except for correcting the cases
where a variable had type int when it should have been HOST_WIDE_INT.

If this patch seems OK, I'll change alias_set_type in a simple
follow-on patch.

Bootstrapped and tested on i686-pc-linux-gnu.  I plan to commit this
in a couple of days unless I get comments.

Ian


gcc/ChangeLog:
2007-08-09  Ian Lance Taylor  <iant@google.com>

	* alias.h (alias_set_type): Define new type.
	(ALIAS_SET_MEMORY_BARRIER): Use it.
	* rtl.h: Include alias.h.
	(struct mem_attrs): Use alias_set_type.
	* tree.h: Include alias.h
	(struct tree_type): Use alias_set_type.
	(struct tree_struct_field_tag): Likewise.
	(struct tree_decl_common): Likewise.
	* alias.c (struct alias_set_entry): Use alias_set_type.
	(get_alias_set_entry, alias_set_subset_of): Likewise.
	(alias_sets_conflict_p): Likewise.
	(alias_sets_must_conflict_p): Likewise.
	(objects_must_conflict_p): Likewise.
	(get_alias_set, new_alias_set): Likewise.
	(record_alias_subset, record_component_aliases): Likewise.
	(varargs_set, frame_set): Change to alias_set_type.
	(get_varargs_alias_set): Use alias_set_type.
	(get_frame_alias_set): Likewise.
	* builtins.c (setjmp_alias_set): Change to alias_set_type.
	* dse.c (struct store_info): Use alias_set_type.
	(struct read_info, struct clear_alias_mode_holder): Likewise.
	(clear_alias_set_lookup, canon_address): Likewise.
	(record_store, check_mem_read_rtx): Likewise.
	(dse_record_singleton_alias_set): Likewise.
	(dse_invalidate_singleton_alias_set): Likewise.
	* emit-rtl.c (get_mem_attrs): Likewise.
	(set_mem_attributes_minus_bitpos): Likewise.
	(set_mem_alias_set): Likewise.
	* expr.c (store_constructor_field, store_field): Likewise.
	* gimplify.c (struct gimplify_init_ctor_preeval_data): Likewise.
	* langhooks.c (lhd_get_alias_set): Likewise.
	* langhooks-def.h (lhd_get_alias_set): Likewise.
	* reload1.c (alter_reg): Likewise.
	* tree-flow.h (struct fieldoff): Likewise.
	* tree-ssa-alias.c (struct alias_map_d): Likewise.
	(may_alias_p, get_smt_for, create_sft): Likewise.
	* tree-ssa-alias-warnings.c (nonstandard_alias_types_p): Likewise.
	* tree-ssa-structalias.c (set_uids_in_ptset): Likewise.
	(merge_smts_into): Likewise.
	* varasm.c (const_alias_set): Likewise.
	* c-common.c (strict_aliasing_warning): Likewise.
	(c_common_get_alias_set): Likewise.
	* dse.h (dse_record_singleton_alias_set): Update declaration.
	(dse_invalidate_singleton_alias_set): Likewise.
	* emit-rtl.h (set_mem_alias_set): Likewise.
	* c-common.h (c_common_get_alias_set): Likewise.
	* print-rtl.c (print_rtx): Cast MEM_ALIAS_SET when printing it.
	* print-tree.c (print_node): Likewise.
	* config/alpha/alpha.c (alpha_sr_alias_set): Change to
	alias_set_type.
	(alpha_setup_incoming_varargs): Use alias_set_type.
	* config/i386/i386.c (setup_incoming_varargs_64): Use
	alias_set_type.
	(setup_incoming_varargs_ms_64): Likewise.
	(ix86_GOT_alias_set): Likewise.
	* config/mn10300/mn10300.c (mn10300_builtin_saveregs): Likewise.
	* config/rs6000/rs6000.c (setup_incoming_varargs): Likewise.
	(set): Change to alias_set_type.
	(get_TOC_alias_set): Use alias_set_type.
	* config/rs6000/rs6000-protos.h (get_TOC_alias_set): Update
	declaration.
	* config/sh/sh.c (sh_builtin_saveregs): Use alias_set_type.
	* config/sparc/sparc.c (sparc_sr_alias_set): Change to
	alias_set_type.
	(struct_value_alias_set): Likewise.
	* Makefile.in (GTFILES): Add $(srcdir)/alias.h.

gcc/ada/ChangeLog:
2007-08-09  Ian Lance Taylor  <iant@google.com>

	* misc.c (gnat_get_alias_set): Change return type to
	alias_set_type.

gcc/cp/ChangeLog:
2007-08-09  Ian Lance Taylor  <iant@google.com>

	* cp-objcp-common.c (cxx_get_alias_set): Change return type to
	alias_set_type.
	* cp/cp-tree.h (cxx_get_alias_set): Update declaration.

gcc/fortran/ChangeLog:
2007-08-09  Ian Lance Taylor  <iant@google.com>

	* f95-lang.c (gfc_get_alias_set): Change return type to
	alias_set_type.

Attachment: foo.patch.gz
Description: alias_set_type patch