/* Global type comparison cache. */
static htab_t gtc_visited;
static struct obstack gtc_ob;
-static htab_t gtc_visited2;
-static struct obstack gtc_ob2;
/* All the tuples have their operand vector (if present) at the very bottom
of the structure. Therefore, the offset required to find the
return false;
}
-
/* Helper for gimple_could_trap_p and gimple_assign_rhs_could_trap_p.
- Return true if S can trap. If INCLUDE_LHS is true and S is a
- GIMPLE_ASSIGN, the LHS of the assignment is also checked.
- Otherwise, only the RHS of the assignment is checked. */
+ Return true if S can trap. When INCLUDE_MEM is true, check whether
+ the memory operations could trap. When INCLUDE_STORES is true and
+ S is a GIMPLE_ASSIGN, the LHS of the assignment is also checked. */
-static bool
-gimple_could_trap_p_1 (gimple s, bool include_lhs)
+bool
+gimple_could_trap_p_1 (gimple s, bool include_mem, bool include_stores)
{
- unsigned i, start;
tree t, div = NULL_TREE;
enum tree_code op;
- start = (is_gimple_assign (s) && !include_lhs) ? 1 : 0;
+ if (include_mem)
+ {
+ unsigned i, start = (is_gimple_assign (s) && !include_stores) ? 1 : 0;
- for (i = start; i < gimple_num_ops (s); i++)
- if (tree_could_trap_p (gimple_op (s, i)))
- return true;
+ for (i = start; i < gimple_num_ops (s); i++)
+ if (tree_could_trap_p (gimple_op (s, i)))
+ return true;
+ }
switch (gimple_code (s))
{
}
return false;
-
}
-
/* Return true if statement S can trap. */
bool
gimple_could_trap_p (gimple s)
{
- return gimple_could_trap_p_1 (s, true);
+ return gimple_could_trap_p_1 (s, true, true);
}
-
/* Return true if RHS of a GIMPLE_ASSIGN S can trap. */
bool
gimple_assign_rhs_could_trap_p (gimple s)
{
gcc_assert (is_gimple_assign (s));
- return gimple_could_trap_p_1 (s, false);
+ return gimple_could_trap_p_1 (s, true, false);
}
if (TREE_CODE (t) == MEM_REF
&& TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR)
t = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
+ else if (TREE_CODE (t) == TARGET_MEM_REF
+ && TMR_SYMBOL (t))
+ t = TMR_SYMBOL (t);
if (SSA_VAR_P (t)
|| TREE_CODE (t) == STRING_CST
/* Structure used to maintain a cache of some type pairs compared by
gimple_types_compatible_p when comparing aggregate types. There are
- four possible values for SAME_P:
+ three possible values for SAME_P:
-2: The pair (T1, T2) has just been inserted in the table.
- -1: The pair (T1, T2) is currently being compared.
0: T1 and T2 are different types.
1: T1 and T2 are the same type.
- This table is only used when comparing aggregate types to avoid
- infinite recursion due to self-referential types. */
+ The two elements in the SAME_P array are indexed by the comparison
+ mode gtc_mode. */
+
struct type_pair_d
{
unsigned int uid1;
unsigned int uid2;
- int same_p;
+ signed char same_p[2];
};
typedef struct type_pair_d *type_pair_t;
+DEF_VEC_P(type_pair_t);
+DEF_VEC_ALLOC_P(type_pair_t,heap);
+
/* Return a hash value for the type pair pointed-to by P. */
static hashval_t
p = XOBNEW (ob_p, struct type_pair_d);
p->uid1 = TYPE_UID (t1);
p->uid2 = TYPE_UID (t2);
- p->same_p = -2;
+ p->same_p[0] = -2;
+ p->same_p[1] = -2;
*slot = (void *) p;
}
return p;
}
+/* Per pointer state for the SCC finding. The on_sccstack flag
+ is not strictly required, it is true when there is no hash value
+ recorded for the type and false otherwise. But querying that
+ is slower. */
+
+struct sccs
+{
+ unsigned int dfsnum;
+ unsigned int low;
+ bool on_sccstack;
+ union {
+ hashval_t hash;
+ signed char same_p;
+ } u;
+};
+
+static unsigned int next_dfs_num;
+static unsigned int gtc_next_dfs_num;
/* Return true if T1 and T2 have the same name. If FOR_COMPLETION_P is
true then if any type has no name return false, otherwise return
return false;
}
-/* Return 1 iff T1 and T2 are structurally identical.
- Otherwise, return 0. */
+static bool
+gimple_types_compatible_p_1 (tree, tree, enum gtc_mode, type_pair_t,
+ VEC(type_pair_t, heap) **,
+ struct pointer_map_t *, struct obstack *);
+
+/* DFS visit the edge from the callers type pair with state *STATE to
+ the pair T1, T2 while operating in FOR_MERGING_P mode.
+ Update the merging status if it is not part of the SCC containing the
+ callers pair and return it.
+ SCCSTACK, SCCSTATE and SCCSTATE_OBSTACK are state for the DFS walk done. */
-bool
-gimple_types_compatible_p (tree t1, tree t2, bool for_merging_p)
+static bool
+gtc_visit (tree t1, tree t2, enum gtc_mode mode,
+ struct sccs *state,
+ VEC(type_pair_t, heap) **sccstack,
+ struct pointer_map_t *sccstate,
+ struct obstack *sccstate_obstack)
{
- type_pair_t p = NULL;
+ struct sccs *cstate = NULL;
+ type_pair_t p;
+ void **slot;
/* Check first for the obvious case of pointer identity. */
if (t1 == t2)
- return 1;
+ return true;
/* Check that we have two types to compare. */
if (t1 == NULL_TREE || t2 == NULL_TREE)
- return 0;
+ return false;
+
+ /* If the types have been previously registered and found equal
+ they still are. */
+ if (TYPE_CANONICAL (t1)
+ && TYPE_CANONICAL (t1) == TYPE_CANONICAL (t2))
+ return true;
/* Can't be the same type if the types don't have the same code. */
if (TREE_CODE (t1) != TREE_CODE (t2))
- return 0;
+ return false;
/* Can't be the same type if they have different CV qualifiers. */
if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
- return 0;
+ return false;
/* Void types are always the same. */
if (TREE_CODE (t1) == VOID_TYPE)
- return 1;
+ return true;
/* Do some simple checks before doing three hashtable queries. */
if (INTEGRAL_TYPE_P (t1)
|| TYPE_PRECISION (t1) != TYPE_PRECISION (t2)
|| TYPE_MODE (t1) != TYPE_MODE (t2)
|| TYPE_UNSIGNED (t1) != TYPE_UNSIGNED (t2))
- return 0;
+ return false;
if (TREE_CODE (t1) == INTEGER_TYPE
&& (TYPE_IS_SIZETYPE (t1) != TYPE_IS_SIZETYPE (t2)
|| TYPE_STRING_FLAG (t1) != TYPE_STRING_FLAG (t2)))
- return 0;
+ return false;
/* That's all we need to check for float and fixed-point types. */
if (SCALAR_FLOAT_TYPE_P (t1)
|| FIXED_POINT_TYPE_P (t1))
- return 1;
-
- /* Perform cheap tail-recursion for vector and complex types. */
- if (TREE_CODE (t1) == VECTOR_TYPE
- || TREE_CODE (t1) == COMPLEX_TYPE)
- return gimple_types_compatible_p (TREE_TYPE (t1), TREE_TYPE (t2),
- for_merging_p);
+ return true;
/* For integral types fall thru to more complex checks. */
}
/* Can't be the same type if they have different alignment or mode. */
if (TYPE_ALIGN (t1) != TYPE_ALIGN (t2)
|| TYPE_MODE (t1) != TYPE_MODE (t2))
- return 0;
+ return false;
}
/* If the hash values of t1 and t2 are different the types can't
possibly be the same. This helps keeping the type-pair hashtable
small, only tracking comparisons for hash collisions. */
if (gimple_type_hash (t1) != gimple_type_hash (t2))
- return 0;
+ return false;
- /* If we've visited this type pair before (in the case of aggregates
- with self-referential types), and we made a decision, return it. */
- p = lookup_type_pair (t1, t2,
- for_merging_p ? >c_visited : >c_visited2,
- for_merging_p ? >c_ob : >c_ob2);
- if (p->same_p == 0 || p->same_p == 1)
+ /* Allocate a new cache entry for this comparison. */
+ p = lookup_type_pair (t1, t2, >c_visited, >c_ob);
+ if (p->same_p[mode] == 0 || p->same_p[mode] == 1)
{
/* We have already decided whether T1 and T2 are the
same, return the cached result. */
- return p->same_p == 1;
+ return p->same_p[mode] == 1;
}
- else if (p->same_p == -1)
+
+ if ((slot = pointer_map_contains (sccstate, p)) != NULL)
+ cstate = (struct sccs *)*slot;
+ if (!cstate)
{
- /* We are currently comparing this pair of types, assume
- that they are the same and let the caller decide. */
- return 1;
+ bool res;
+ /* Not yet visited. DFS recurse. */
+ res = gimple_types_compatible_p_1 (t1, t2, mode, p,
+ sccstack, sccstate, sccstate_obstack);
+ if (!cstate)
+ cstate = (struct sccs *)* pointer_map_contains (sccstate, p);
+ state->low = MIN (state->low, cstate->low);
+ /* If the type is no longer on the SCC stack and thus is not part
+ of the parents SCC, return its state. Otherwise we will
+ ignore this pair and assume equality. */
+ if (!cstate->on_sccstack)
+ return res;
}
+ if (cstate->dfsnum < state->dfsnum
+ && cstate->on_sccstack)
+ state->low = MIN (cstate->dfsnum, state->low);
+
+ /* We are part of our parents SCC, skip this entry and return true. */
+ return true;
+}
+
+/* Worker for gimple_types_compatible.
+ SCCSTACK, SCCSTATE and SCCSTATE_OBSTACK are state for the DFS walk done. */
+
+static bool
+gimple_types_compatible_p_1 (tree t1, tree t2, enum gtc_mode mode,
+ type_pair_t p,
+ VEC(type_pair_t, heap) **sccstack,
+ struct pointer_map_t *sccstate,
+ struct obstack *sccstate_obstack)
+{
+ struct sccs *state;
+
+ gcc_assert (p->same_p[mode] == -2);
- gcc_assert (p->same_p == -2);
+ state = XOBNEW (sccstate_obstack, struct sccs);
+ *pointer_map_insert (sccstate, p) = state;
- /* Mark the (T1, T2) comparison in progress. */
- p->same_p = -1;
+ VEC_safe_push (type_pair_t, heap, *sccstack, p);
+ state->dfsnum = gtc_next_dfs_num++;
+ state->low = state->dfsnum;
+ state->on_sccstack = true;
/* If their attributes are not the same they can't be the same type. */
if (!attribute_list_equal (TYPE_ATTRIBUTES (t1), TYPE_ATTRIBUTES (t2)))
/* Do type-specific comparisons. */
switch (TREE_CODE (t1))
{
+ case VECTOR_TYPE:
+ case COMPLEX_TYPE:
+ if (!gtc_visit (TREE_TYPE (t1), TREE_TYPE (t2), mode,
+ state, sccstack, sccstate, sccstate_obstack))
+ goto different_types;
+ goto same_types;
+
case ARRAY_TYPE:
/* Array types are the same if the element types are the same and
the number of elements are the same. */
- if (!gimple_types_compatible_p (TREE_TYPE (t1), TREE_TYPE (t2),
- for_merging_p)
+ if (!gtc_visit (TREE_TYPE (t1), TREE_TYPE (t2), mode,
+ state, sccstack, sccstate, sccstate_obstack)
|| TYPE_STRING_FLAG (t1) != TYPE_STRING_FLAG (t2)
|| TYPE_NONALIASED_COMPONENT (t1) != TYPE_NONALIASED_COMPONENT (t2))
goto different_types;
case METHOD_TYPE:
/* Method types should belong to the same class. */
- if (!gimple_types_compatible_p (TYPE_METHOD_BASETYPE (t1),
- TYPE_METHOD_BASETYPE (t2), for_merging_p))
+ if (!gtc_visit (TYPE_METHOD_BASETYPE (t1), TYPE_METHOD_BASETYPE (t2),
+ mode, state, sccstack, sccstate, sccstate_obstack))
goto different_types;
/* Fallthru */
case FUNCTION_TYPE:
/* Function types are the same if the return type and arguments types
are the same. */
- if ((for_merging_p
+ if ((mode != GTC_DIAG
|| !gimple_compatible_complete_and_incomplete_subtype_p
(TREE_TYPE (t1), TREE_TYPE (t2)))
- && !gimple_types_compatible_p (TREE_TYPE (t1), TREE_TYPE (t2),
- for_merging_p))
+ && !gtc_visit (TREE_TYPE (t1), TREE_TYPE (t2), mode,
+ state, sccstack, sccstate, sccstate_obstack))
goto different_types;
if (!targetm.comp_type_attributes (t1, t2))
parms1 && parms2;
parms1 = TREE_CHAIN (parms1), parms2 = TREE_CHAIN (parms2))
{
- if ((for_merging_p
+ if ((mode == GTC_MERGE
|| !gimple_compatible_complete_and_incomplete_subtype_p
(TREE_VALUE (parms1), TREE_VALUE (parms2)))
- && !gimple_types_compatible_p (TREE_VALUE (parms1),
- TREE_VALUE (parms2),
- for_merging_p))
+ && !gtc_visit (TREE_VALUE (parms1), TREE_VALUE (parms2), mode,
+ state, sccstack, sccstate, sccstate_obstack))
goto different_types;
}
case OFFSET_TYPE:
{
- if (!gimple_types_compatible_p (TREE_TYPE (t1), TREE_TYPE (t2),
- for_merging_p)
- || !gimple_types_compatible_p (TYPE_OFFSET_BASETYPE (t1),
- TYPE_OFFSET_BASETYPE (t2),
- for_merging_p))
+ if (!gtc_visit (TREE_TYPE (t1), TREE_TYPE (t2), mode,
+ state, sccstack, sccstate, sccstate_obstack)
+ || !gtc_visit (TYPE_OFFSET_BASETYPE (t1),
+ TYPE_OFFSET_BASETYPE (t2), mode,
+ state, sccstack, sccstate, sccstate_obstack))
goto different_types;
goto same_types;
/* If one pointer points to an incomplete type variant of
the other pointed-to type they are the same. */
- if (!for_merging_p
+ if (mode == GTC_DIAG
&& gimple_compatible_complete_and_incomplete_subtype_p
(TREE_TYPE (t1), TREE_TYPE (t2)))
goto same_types;
/* Otherwise, pointer and reference types are the same if the
pointed-to types are the same. */
- if (gimple_types_compatible_p (TREE_TYPE (t1), TREE_TYPE (t2),
- for_merging_p))
+ if (gtc_visit (TREE_TYPE (t1), TREE_TYPE (t2), mode,
+ state, sccstack, sccstate, sccstate_obstack))
goto same_types;
goto different_types;
if (DECL_NAME (f1) != DECL_NAME (f2)
|| DECL_NONADDRESSABLE_P (f1) != DECL_NONADDRESSABLE_P (f2)
|| !gimple_compare_field_offset (f1, f2)
- || !gimple_types_compatible_p (TREE_TYPE (f1),
- TREE_TYPE (f2), for_merging_p))
+ || !gtc_visit (TREE_TYPE (f1), TREE_TYPE (f2), mode,
+ state, sccstack, sccstate, sccstate_obstack))
goto different_types;
}
/* Common exit path for types that are not compatible. */
different_types:
- p->same_p = 0;
- return 0;
+ state->u.same_p = 0;
+ goto pop;
/* Common exit path for types that are compatible. */
same_types:
- p->same_p = 1;
- return 1;
-}
+ state->u.same_p = 1;
+ goto pop;
+pop:
+ if (state->low == state->dfsnum)
+ {
+ type_pair_t x;
+ /* Pop off the SCC and set its cache values. */
+ do
+ {
+ struct sccs *cstate;
+ x = VEC_pop (type_pair_t, *sccstack);
+ cstate = (struct sccs *)*pointer_map_contains (sccstate, x);
+ cstate->on_sccstack = false;
+ x->same_p[mode] = cstate->u.same_p;
+ }
+ while (x != p);
+ }
+ return state->u.same_p;
+}
-/* Per pointer state for the SCC finding. The on_sccstack flag
- is not strictly required, it is true when there is no hash value
- recorded for the type and false otherwise. But querying that
- is slower. */
+/* Return true iff T1 and T2 are structurally identical. When
+ FOR_MERGING_P is true the an incomplete type and a complete type
+ are considered different, otherwise they are considered compatible. */
-struct sccs
+bool
+gimple_types_compatible_p (tree t1, tree t2, enum gtc_mode mode)
{
- unsigned int dfsnum;
- unsigned int low;
- bool on_sccstack;
- hashval_t hash;
-};
+ VEC(type_pair_t, heap) *sccstack = NULL;
+ struct pointer_map_t *sccstate;
+ struct obstack sccstate_obstack;
+ type_pair_t p = NULL;
+ bool res;
+
+ /* Before starting to set up the SCC machinery handle simple cases. */
+
+ /* Check first for the obvious case of pointer identity. */
+ if (t1 == t2)
+ return true;
+
+ /* Check that we have two types to compare. */
+ if (t1 == NULL_TREE || t2 == NULL_TREE)
+ return false;
+
+ /* If the types have been previously registered and found equal
+ they still are. */
+ if (TYPE_CANONICAL (t1)
+ && TYPE_CANONICAL (t1) == TYPE_CANONICAL (t2))
+ return true;
+
+ /* Can't be the same type if the types don't have the same code. */
+ if (TREE_CODE (t1) != TREE_CODE (t2))
+ return false;
+
+ /* Can't be the same type if they have different CV qualifiers. */
+ if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
+ return false;
+
+ /* Void types are always the same. */
+ if (TREE_CODE (t1) == VOID_TYPE)
+ return true;
+
+ /* Do some simple checks before doing three hashtable queries. */
+ if (INTEGRAL_TYPE_P (t1)
+ || SCALAR_FLOAT_TYPE_P (t1)
+ || FIXED_POINT_TYPE_P (t1)
+ || TREE_CODE (t1) == VECTOR_TYPE
+ || TREE_CODE (t1) == COMPLEX_TYPE
+ || TREE_CODE (t1) == OFFSET_TYPE)
+ {
+ /* Can't be the same type if they have different alignment,
+ sign, precision or mode. */
+ if (TYPE_ALIGN (t1) != TYPE_ALIGN (t2)
+ || TYPE_PRECISION (t1) != TYPE_PRECISION (t2)
+ || TYPE_MODE (t1) != TYPE_MODE (t2)
+ || TYPE_UNSIGNED (t1) != TYPE_UNSIGNED (t2))
+ return false;
+
+ if (TREE_CODE (t1) == INTEGER_TYPE
+ && (TYPE_IS_SIZETYPE (t1) != TYPE_IS_SIZETYPE (t2)
+ || TYPE_STRING_FLAG (t1) != TYPE_STRING_FLAG (t2)))
+ return false;
+
+ /* That's all we need to check for float and fixed-point types. */
+ if (SCALAR_FLOAT_TYPE_P (t1)
+ || FIXED_POINT_TYPE_P (t1))
+ return true;
+
+ /* For integral types fall thru to more complex checks. */
+ }
+
+ else if (AGGREGATE_TYPE_P (t1) || POINTER_TYPE_P (t1))
+ {
+ /* Can't be the same type if they have different alignment or mode. */
+ if (TYPE_ALIGN (t1) != TYPE_ALIGN (t2)
+ || TYPE_MODE (t1) != TYPE_MODE (t2))
+ return false;
+ }
+
+ /* If the hash values of t1 and t2 are different the types can't
+ possibly be the same. This helps keeping the type-pair hashtable
+ small, only tracking comparisons for hash collisions. */
+ if (gimple_type_hash (t1) != gimple_type_hash (t2))
+ return false;
+
+ /* If we've visited this type pair before (in the case of aggregates
+ with self-referential types), and we made a decision, return it. */
+ p = lookup_type_pair (t1, t2, >c_visited, >c_ob);
+ if (p->same_p[mode] == 0 || p->same_p[mode] == 1)
+ {
+ /* We have already decided whether T1 and T2 are the
+ same, return the cached result. */
+ return p->same_p[mode] == 1;
+ }
+
+ /* Now set up the SCC machinery for the comparison. */
+ gtc_next_dfs_num = 1;
+ sccstate = pointer_map_create ();
+ gcc_obstack_init (&sccstate_obstack);
+ res = gimple_types_compatible_p_1 (t1, t2, mode, p,
+ &sccstack, sccstate, &sccstate_obstack);
+ VEC_free (type_pair_t, heap, sccstack);
+ pointer_map_destroy (sccstate);
+ obstack_free (&sccstate_obstack, NULL);
+
+ return res;
+}
-static unsigned int next_dfs_num;
static hashval_t
iterative_hash_gimple_type (tree, hashval_t, VEC(tree, heap) **,
}
/* Record hash for us. */
- state->hash = v;
+ state->u.hash = v;
/* See if we found an SCC. */
if (state->low == state->dfsnum)
cstate = (struct sccs *)*pointer_map_contains (sccstate, x);
cstate->on_sccstack = false;
slot = pointer_map_insert (type_hash_cache, x);
- *slot = (void *) (size_t) cstate->hash;
+ *slot = (void *) (size_t) cstate->u.hash;
}
while (x != type);
}
const_tree t1 = (const_tree) p1;
const_tree t2 = (const_tree) p2;
return gimple_types_compatible_p (CONST_CAST_TREE (t1),
- CONST_CAST_TREE (t2), true);
+ CONST_CAST_TREE (t2), GTC_MERGE);
}
gcc_assert (TYPE_P (t));
/* In TYPE_CANONICAL we cache the result of gimple_register_type.
- It is initially set to NULL during LTO streaming. */
- if (TYPE_CANONICAL (t))
+ It is initially set to NULL during LTO streaming.
+ But do not mess with TYPE_CANONICAL when not in WPA or link phase. */
+ if (in_lto_p && TYPE_CANONICAL (t))
return TYPE_CANONICAL (t);
/* Always register the main variant first. This is important so we
TYPE_NEXT_REF_TO (t) = NULL_TREE;
}
- TYPE_CANONICAL (t) = new_type;
+ if (in_lto_p)
+ TYPE_CANONICAL (t) = new_type;
t = new_type;
}
else
{
- TYPE_CANONICAL (t) = t;
+ if (in_lto_p)
+ TYPE_CANONICAL (t) = t;
*slot = (void *) t;
}
else
fprintf (stderr, "GIMPLE type table is empty\n");
if (gtc_visited)
- fprintf (stderr, "GIMPLE type merging comparison table: size %ld, %ld "
+ fprintf (stderr, "GIMPLE type comparison table: size %ld, %ld "
"elements, %ld searches, %ld collisions (ratio: %f)\n",
(long) htab_size (gtc_visited),
(long) htab_elements (gtc_visited),
(long) gtc_visited->collisions,
htab_collisions (gtc_visited));
else
- fprintf (stderr, "GIMPLE type merging comparison table is empty\n");
- if (gtc_visited2)
- fprintf (stderr, "GIMPLE type comparison table: size %ld, %ld "
- "elements, %ld searches, %ld collisions (ratio: %f)\n",
- (long) htab_size (gtc_visited2),
- (long) htab_elements (gtc_visited2),
- (long) gtc_visited2->searches,
- (long) gtc_visited2->collisions,
- htab_collisions (gtc_visited2));
- else
fprintf (stderr, "GIMPLE type comparison table is empty\n");
}
obstack_free (>c_ob, NULL);
gtc_visited = NULL;
}
- if (gtc_visited2)
- {
- htab_delete (gtc_visited2);
- obstack_free (>c_ob2, NULL);
- gtc_visited2 = NULL;
- }
}
if (t1 != t)
return get_alias_set (t1);
}
- else if (POINTER_TYPE_P (t))
- {
- /* From the common C and C++ langhook implementation:
-
- Unfortunately, there is no canonical form of a pointer type.
- In particular, if we have `typedef int I', then `int *', and
- `I *' are different types. So, we have to pick a canonical
- representative. We do this below.
-
- Technically, this approach is actually more conservative that
- it needs to be. In particular, `const int *' and `int *'
- should be in different alias sets, according to the C and C++
- standard, since their types are not the same, and so,
- technically, an `int **' and `const int **' cannot point at
- the same thing.
-
- But, the standard is wrong. In particular, this code is
- legal C++:
-
- int *ip;
- int **ipp = &ip;
- const int* const* cipp = ipp;
- And, it doesn't make sense for that to be legal unless you
- can dereference IPP and CIPP. So, we ignore cv-qualifiers on
- the pointed-to types. This issue has been reported to the
- C++ committee. */
-
- /* In addition to the above canonicalization issue with LTO
- we should also canonicalize `T (*)[]' to `T *' avoiding
- alias issues with pointer-to element types and pointer-to
- array types.
-
- Likewise we need to deal with the situation of incomplete
- pointed-to types and make `*(struct X **)&a' and
- `*(struct X {} **)&a' alias. Otherwise we will have to
- guarantee that all pointer-to incomplete type variants
- will be replaced by pointer-to complete type variants if
- they are available.
-
- With LTO the convenient situation of using `void *' to
- access and store any pointer type will also become
- more apparent (and `void *' is just another pointer-to
- incomplete type). Assigning alias-set zero to `void *'
- and all pointer-to incomplete types is a not appealing
- solution. Assigning an effective alias-set zero only
- affecting pointers might be - by recording proper subset
- relationships of all pointer alias-sets.
-
- Pointer-to function types are another grey area which
- needs caution. Globbing them all into one alias-set
- or the above effective zero set would work. */
-
- /* For now just assign the same alias-set to all pointers.
- That's simple and avoids all the above problems. */
- if (t != ptr_type_node)
- return get_alias_set (ptr_type_node);
- }
return -1;
}
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