}
}
+
+/* Return whether the pointer-type T effective for aliasing may
+ access everything and thus the reference has to be assigned
+ alias-set zero. */
+
+static bool
+ref_all_alias_ptr_type_p (const_tree t)
+{
+ return (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE
+ || TYPE_REF_CAN_ALIAS_ALL (t));
+}
+
/* Return the alias set for the memory pointed to by T, which may be
either a type or an expression. Return -1 if there is nothing
special about dereferencing T. */
static alias_set_type
get_deref_alias_set_1 (tree t)
{
- /* If we're not doing any alias analysis, just assume everything
- aliases everything else. */
- if (!flag_strict_aliasing)
- return 0;
-
/* All we care about is the type. */
if (! TYPE_P (t))
t = TREE_TYPE (t);
/* If we have an INDIRECT_REF via a void pointer, we don't
know anything about what that might alias. Likewise if the
pointer is marked that way. */
- if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE
- || TYPE_REF_CAN_ALIAS_ALL (t))
+ if (ref_all_alias_ptr_type_p (t))
return 0;
return -1;
alias_set_type
get_deref_alias_set (tree t)
{
+ /* If we're not doing any alias analysis, just assume everything
+ aliases everything else. */
+ if (!flag_strict_aliasing)
+ return 0;
+
alias_set_type set = get_deref_alias_set_1 (t);
/* Fall back to the alias-set of the pointed-to type. */
return set;
}
+/* Return the pointer-type relevant for TBAA purposes from the
+ memory reference tree *T or NULL_TREE in which case *T is
+ adjusted to point to the outermost component reference that
+ can be used for assigning an alias set. */
+
+static tree
+reference_alias_ptr_type_1 (tree *t)
+{
+ tree inner;
+
+ /* Get the base object of the reference. */
+ inner = *t;
+ while (handled_component_p (inner))
+ {
+ /* If there is a VIEW_CONVERT_EXPR in the chain we cannot use
+ the type of any component references that wrap it to
+ determine the alias-set. */
+ if (TREE_CODE (inner) == VIEW_CONVERT_EXPR)
+ *t = TREE_OPERAND (inner, 0);
+ inner = TREE_OPERAND (inner, 0);
+ }
+
+ /* Handle pointer dereferences here, they can override the
+ alias-set. */
+ if (INDIRECT_REF_P (inner)
+ && ref_all_alias_ptr_type_p (TREE_TYPE (TREE_OPERAND (inner, 0))))
+ return TREE_TYPE (TREE_OPERAND (inner, 0));
+ else if (TREE_CODE (inner) == TARGET_MEM_REF)
+ return TREE_TYPE (TMR_OFFSET (inner));
+ else if (TREE_CODE (inner) == MEM_REF
+ && ref_all_alias_ptr_type_p (TREE_TYPE (TREE_OPERAND (inner, 1))))
+ return TREE_TYPE (TREE_OPERAND (inner, 1));
+
+ /* If the innermost reference is a MEM_REF that has a
+ conversion embedded treat it like a VIEW_CONVERT_EXPR above,
+ using the memory access type for determining the alias-set. */
+ if (TREE_CODE (inner) == MEM_REF
+ && (TYPE_MAIN_VARIANT (TREE_TYPE (inner))
+ != TYPE_MAIN_VARIANT
+ (TREE_TYPE (TREE_TYPE (TREE_OPERAND (inner, 1))))))
+ return TREE_TYPE (TREE_OPERAND (inner, 1));
+
+ /* Otherwise, pick up the outermost object that we could have a pointer
+ to, processing conversions as above. */
+ /* ??? Ick, this is worse than quadratic! */
+ while (component_uses_parent_alias_set (*t))
+ {
+ *t = TREE_OPERAND (*t, 0);
+ STRIP_NOPS (*t);
+ }
+
+ return NULL_TREE;
+}
+
+/* Return the pointer-type relevant for TBAA purposes from the
+ gimple memory reference tree T. This is the type to be used for
+ the offset operand of MEM_REF or TARGET_MEM_REF replacements of T
+ and guarantees that get_alias_set will return the same alias
+ set for T and the replacement. */
+
+tree
+reference_alias_ptr_type (tree t)
+{
+ tree ptype = reference_alias_ptr_type_1 (&t);
+ /* If there is a given pointer type for aliasing purposes, return it. */
+ if (ptype != NULL_TREE)
+ return ptype;
+
+ /* Otherwise build one from the outermost component reference we
+ may use. */
+ if (TREE_CODE (t) == MEM_REF
+ || TREE_CODE (t) == TARGET_MEM_REF)
+ return TREE_TYPE (TREE_OPERAND (t, 1));
+ else
+ return build_pointer_type (TYPE_MAIN_VARIANT (TREE_TYPE (t)));
+}
+
+/* Return whether the pointer-types T1 and T2 used to determine
+ two alias sets of two references will yield the same answer
+ from get_deref_alias_set. */
+
+bool
+alias_ptr_types_compatible_p (tree t1, tree t2)
+{
+ if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
+ return true;
+
+ if (ref_all_alias_ptr_type_p (t1)
+ || ref_all_alias_ptr_type_p (t2))
+ return false;
+
+ return (TYPE_MAIN_VARIANT (TREE_TYPE (t1))
+ == TYPE_MAIN_VARIANT (TREE_TYPE (t2)));
+}
+
/* Return the alias set for T, which may be either a type or an
expression. Call language-specific routine for help, if needed. */
aren't types. */
if (! TYPE_P (t))
{
- tree inner;
-
/* Give the language a chance to do something with this tree
before we look at it. */
STRIP_NOPS (t);
if (set != -1)
return set;
- /* Get the base object of the reference. */
- inner = t;
- while (handled_component_p (inner))
- {
- /* If there is a VIEW_CONVERT_EXPR in the chain we cannot use
- the type of any component references that wrap it to
- determine the alias-set. */
- if (TREE_CODE (inner) == VIEW_CONVERT_EXPR)
- t = TREE_OPERAND (inner, 0);
- inner = TREE_OPERAND (inner, 0);
- }
-
- /* Handle pointer dereferences here, they can override the
- alias-set. */
- if (INDIRECT_REF_P (inner))
- {
- set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0));
- if (set != -1)
- return set;
- }
- else if (TREE_CODE (inner) == TARGET_MEM_REF)
- return get_deref_alias_set (TMR_OFFSET (inner));
- else if (TREE_CODE (inner) == MEM_REF)
- {
- set = get_deref_alias_set_1 (TREE_OPERAND (inner, 1));
- if (set != -1)
- return set;
- }
-
- /* If the innermost reference is a MEM_REF that has a
- conversion embedded treat it like a VIEW_CONVERT_EXPR above,
- using the memory access type for determining the alias-set. */
- if (TREE_CODE (inner) == MEM_REF
- && TYPE_MAIN_VARIANT (TREE_TYPE (inner))
- != TYPE_MAIN_VARIANT
- (TREE_TYPE (TREE_TYPE (TREE_OPERAND (inner, 1)))))
- return get_deref_alias_set (TREE_OPERAND (inner, 1));
-
- /* Otherwise, pick up the outermost object that we could have a pointer
- to, processing conversions as above. */
- while (component_uses_parent_alias_set (t))
- {
- t = TREE_OPERAND (t, 0);
- STRIP_NOPS (t);
- }
+ /* Get the alias pointer-type to use or the outermost object
+ that we could have a pointer to. */
+ tree ptype = reference_alias_ptr_type_1 (&t);
+ if (ptype != NULL)
+ return get_deref_alias_set (ptype);
/* If we've already determined the alias set for a decl, just return
it. This is necessary for C++ anonymous unions, whose component
projects / platform / upstream / linaro-gcc.git / commitdiff