On Mon, 9 Nov 2020, Jan Hubicka wrote:
> Hi,
> this patch implements cleanup we discussed some time ago on IRC.
> Instead of recording reference types in ipa-modref I record pointer
> types same way as done by RTL attributes and I moved corresponding logic
> to tree-ssa-alias.c.
> Problem is that it breaks some testcases:
>
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr50444.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr50444.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr50444.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr50444.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr52419.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr52419.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr52419.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr52419.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-1.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-1.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-1.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-1.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-2.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-2.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-2.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-2.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-3.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-3.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-3.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-3.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-4.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-4.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-4.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr57748-4.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr58041.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr58041.c -O2 -flto
> -fno-use-linker-plugin -flto-partition=none (test for excess errors)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr58041.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (internal compiler error)
> ./testsuite/gcc/gcc.sum:FAIL: gcc.dg/torture/pr58041.c -O2 -flto
> -fuse-linker-plugin -fno-fat-lto-objects (test for excess errors)
>
> I looked into first one and it is caused by "may_alias" attribute on the
> vector type. This makes build_pointer_type to set that it may alias all
> and the get_deref_alias_type return 0 while ao_ref_alias_set returns 4.
Hmm, why does ao_ref_alias_set return 4? On what reference? Note
that get_ref_alias_ptr_type necessarily gets you a single pointer
type (compared to ao_refs base / ref ones). Still for vector types
this shouldn't make a difference ...
> I can live with this small loss of precision for ipa-modref, but I am
> using same logic in the ao_ref_compare for ipa-icf where we can not be
> conservative. I wonder how to fix this. One option is to keep the
> ipa-modref way of recording actual types that determine alias set rather
> pointers to them, but I recall you considered it confusing to have two
> sets of machineries for this. So perhaps we want to add a way to build
> pointer type ignoring may alias attribute?
But the may-alias type makes a semantic difference ...
So I'm not really understanding the issue here :/ (and sorry for the
delay answering).
Richard.
> I see that RTL needs this to handle alias sets 0 because it also needs
> mathcing type size. I do not need that in TBAA machinery.
>
> Honza
>
> diff --git a/gcc/alias.c b/gcc/alias.c
> index f6d7a1791c4..0b12a89657e 100644
> --- a/gcc/alias.c
> +++ b/gcc/alias.c
> @@ -737,7 +737,7 @@ get_deref_alias_set (tree t)
> adjusted to point to the outermost component reference that
> can be used for assigning an alias set. */
>
> -tree
> +static tree
> reference_alias_ptr_type_1 (tree *t)
> {
> tree inner;
> diff --git a/gcc/alias.h b/gcc/alias.h
> index 807af957f02..4453d9723ce 100644
> --- a/gcc/alias.h
> +++ b/gcc/alias.h
> @@ -36,7 +36,6 @@ extern int objects_must_conflict_p (tree, tree);
> extern int nonoverlapping_memrefs_p (const_rtx, const_rtx, bool);
> extern void dump_alias_stats_in_alias_c (FILE *s);
> tree reference_alias_ptr_type (tree);
> -tree reference_alias_ptr_type_1 (tree *);
> bool alias_ptr_types_compatible_p (tree, tree);
> int compare_base_decls (tree, tree);
> bool refs_same_for_tbaa_p (tree, tree);
> diff --git a/gcc/ipa-modref.c b/gcc/ipa-modref.c
> index 3f46bebed3c..a621b30b1e1 100644
> --- a/gcc/ipa-modref.c
> +++ b/gcc/ipa-modref.c
> @@ -328,7 +328,7 @@ dump_lto_records (modref_records_lto *tt, FILE *out)
> fprintf (out, " Base %i:", (int)i);
> print_generic_expr (dump_file, n->base);
> fprintf (out, " (alias set %i)\n",
> - n->base ? get_alias_set (n->base) : 0);
> + n->base ? get_deref_alias_set (n->base) : 0);
> if (n->every_ref)
> {
> fprintf (out, " Every ref\n");
> @@ -341,7 +341,7 @@ dump_lto_records (modref_records_lto *tt, FILE *out)
> fprintf (out, " Ref %i:", (int)j);
> print_generic_expr (dump_file, r->ref);
> fprintf (out, " (alias set %i)\n",
> - r->ref ? get_alias_set (r->ref) : 0);
> + r->ref ? get_deref_alias_set (r->ref) : 0);
> if (r->every_access)
> {
> fprintf (out, " Every access\n");
> @@ -478,48 +478,18 @@ record_access (modref_records *tt, ao_ref *ref)
> static void
> record_access_lto (modref_records_lto *tt, ao_ref *ref)
> {
> - /* get_alias_set sometimes use different type to compute the alias set
> - than TREE_TYPE (base). Do same adjustments. */
> tree base_type = NULL_TREE, ref_type = NULL_TREE;
> if (flag_strict_aliasing)
> {
> - tree base;
> -
> - base = ref->ref;
> - while (handled_component_p (base))
> - base = TREE_OPERAND (base, 0);
> -
> - base_type = reference_alias_ptr_type_1 (&base);
> -
> - if (!base_type)
> - base_type = TREE_TYPE (base);
> - else
> - base_type = TYPE_REF_CAN_ALIAS_ALL (base_type)
> - ? NULL_TREE : TREE_TYPE (base_type);
> -
> - tree ref_expr = ref->ref;
> - ref_type = reference_alias_ptr_type_1 (&ref_expr);
> -
> - if (!ref_type)
> - ref_type = TREE_TYPE (ref_expr);
> - else
> - ref_type = TYPE_REF_CAN_ALIAS_ALL (ref_type)
> - ? NULL_TREE : TREE_TYPE (ref_type);
> -
> - /* Sanity check that we are in sync with what get_alias_set does. */
> - gcc_checking_assert ((!base_type && !ao_ref_base_alias_set (ref))
> - || get_alias_set (base_type)
> - == ao_ref_base_alias_set (ref));
> - gcc_checking_assert ((!ref_type && !ao_ref_alias_set (ref))
> - || get_alias_set (ref_type)
> - == ao_ref_alias_set (ref));
> + base_type = ao_ref_base_alias_ptr_type (ref);
> + ref_type = ao_ref_alias_ptr_type (ref);
>
> /* Do not bother to record types that have no meaningful alias set.
> Also skip variably modified types since these go to local streams. */
> - if (base_type && (!get_alias_set (base_type)
> + if (base_type && (!get_deref_alias_set (base_type)
> || variably_modified_type_p (base_type, NULL_TREE)))
> base_type = NULL_TREE;
> - if (ref_type && (!get_alias_set (ref_type)
> + if (ref_type && (!get_deref_alias_set (ref_type)
> || variably_modified_type_p (ref_type, NULL_TREE)))
> ref_type = NULL_TREE;
> }
> @@ -529,10 +499,10 @@ record_access_lto (modref_records_lto *tt, ao_ref *ref)
> fprintf (dump_file, " - Recording base type:");
> print_generic_expr (dump_file, base_type);
> fprintf (dump_file, " (alias set %i) ref type:",
> - base_type ? get_alias_set (base_type) : 0);
> + base_type ? get_deref_alias_set (base_type) : 0);
> print_generic_expr (dump_file, ref_type);
> fprintf (dump_file, " (alias set %i) parm:%i\n",
> - ref_type ? get_alias_set (ref_type) : 0,
> + ref_type ? get_deref_alias_set (ref_type) : 0,
> a.parm_index);
> }
>
> @@ -1477,7 +1447,7 @@ read_modref_records (lto_input_block *ib, struct
> data_in *data_in,
> something obviously unnecessary. Do not glob types by alias sets;
> it is not 100% clear that ltrans types will get merged same way.
> Types may get refined based on ODR type conflicts. */
> - if (base_tree && !get_alias_set (base_tree))
> + if (base_tree && !get_deref_alias_set (base_tree))
> {
> if (dump_file)
> {
> @@ -1490,7 +1460,7 @@ read_modref_records (lto_input_block *ib, struct
> data_in *data_in,
>
> if (nolto_ret)
> nolto_base_node = (*nolto_ret)->insert_base (base_tree
> - ? get_alias_set (base_tree)
> + ? get_deref_alias_set
> (base_tree)
> : 0);
> if (lto_ret)
> lto_base_node = (*lto_ret)->insert_base (base_tree);
> @@ -1509,7 +1479,7 @@ read_modref_records (lto_input_block *ib, struct
> data_in *data_in,
> {
> tree ref_tree = stream_read_tree (ib, data_in);
>
> - if (ref_tree && !get_alias_set (ref_tree))
> + if (ref_tree && !get_deref_alias_set (ref_tree))
> {
> if (dump_file)
> {
> @@ -1526,7 +1496,7 @@ read_modref_records (lto_input_block *ib, struct
> data_in *data_in,
> if (nolto_base_node)
> nolto_ref_node
> = nolto_base_node->insert_ref (ref_tree
> - ? get_alias_set (ref_tree) : 0,
> + ? get_deref_alias_set (ref_tree) :
> 0,
> max_refs);
> if (lto_base_node)
> lto_ref_node = lto_base_node->insert_ref (ref_tree, max_refs);
> diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
> index e64011d04df..b4719825167 100644
> --- a/gcc/tree-ssa-alias.c
> +++ b/gcc/tree-ssa-alias.c
> @@ -739,6 +739,38 @@ ao_ref_alias_set (ao_ref *ref)
> return ref->ref_alias_set;
> }
>
> +/* Returns a type satisfying
> + get_deref_alias_set (type) == ao_ref_base_alias_set (REF). */
> +
> +tree
> +ao_ref_base_alias_ptr_type (ao_ref *ref)
> +{
> + tree base_ref;
> +
> + if (!ref->ref)
> + return NULL_TREE;
> + base_ref = ref->ref;
> + while (handled_component_p (base_ref))
> + base_ref = TREE_OPERAND (base_ref, 0);
> + tree ret = reference_alias_ptr_type (base_ref);
> + gcc_checking_assert (get_deref_alias_set (ret) == ao_ref_base_alias_set
> (ref));
> + return ret;
> +}
> +
> +/* Returns a type satisfying
> + get_deref_alias_set (type) == ao_ref_alias_set (REF). */
> +
> +tree
> +ao_ref_alias_ptr_type (ao_ref *ref)
> +{
> + if (!ref->ref)
> + return NULL_TREE;
> + tree ret = reference_alias_ptr_type (ref->ref);
> + gcc_checking_assert (get_deref_alias_set (ret) == ao_ref_alias_set (ref));
> + return ret;
> +}
> +
> +
> /* Init an alias-oracle reference representation from a gimple pointer
> PTR a range specified by OFFSET, SIZE and MAX_SIZE under the assumption
> that RANGE_KNOWN is set.
> diff --git a/gcc/tree-ssa-alias.h b/gcc/tree-ssa-alias.h
> index 1561ead2941..830ac1bf84d 100644
> --- a/gcc/tree-ssa-alias.h
> +++ b/gcc/tree-ssa-alias.h
> @@ -114,6 +114,8 @@ extern void ao_ref_init_from_ptr_and_size (ao_ref *,
> tree, tree);
> extern tree ao_ref_base (ao_ref *);
> extern alias_set_type ao_ref_alias_set (ao_ref *);
> extern alias_set_type ao_ref_base_alias_set (ao_ref *);
> +extern tree ao_ref_alias_ptr_type (ao_ref *);
> +extern tree ao_ref_base_alias_ptr_type (ao_ref *);
> extern bool ptr_deref_may_alias_global_p (tree);
> extern bool ptr_derefs_may_alias_p (tree, tree);
> extern bool ptrs_compare_unequal (tree, tree);
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imend
