+/* Given REF, either a MEM or a REG, and T, either the type of X or
+ the expression corresponding to REF, set RTX_UNCHANGING_P if
+ appropriate. */
+
+void
+maybe_set_unchanging (ref, t)
+ rtx ref;
+ tree t;
+{
+ /* We can set RTX_UNCHANGING_P from TREE_READONLY for decls whose
+ initialization is only executed once, or whose initializer always
+ has the same value. Currently we simplify this to PARM_DECLs in the
+ first case, and decls with TREE_CONSTANT initializers in the second. */
+ if ((TREE_READONLY (t) && DECL_P (t)
+ && (TREE_CODE (t) == PARM_DECL
+ || DECL_INITIAL (t) == NULL_TREE
+ || TREE_CONSTANT (DECL_INITIAL (t))))
+ || TREE_CODE_CLASS (TREE_CODE (t)) == 'c')
+ RTX_UNCHANGING_P (ref) = 1;
+}
+
+/* Given REF, a MEM, and T, either the type of X or the expression
+ corresponding to REF, set the memory attributes. OBJECTP is nonzero
+ if we are making a new object of this type. */
+
+void
+set_mem_attributes (ref, t, objectp)
+ rtx ref;
+ tree t;
+ int objectp;
+{
+ tree type;
+
+ /* It can happen that type_for_mode was given a mode for which there
+ is no language-level type. In which case it returns NULL, which
+ we can see here. */
+ if (t == NULL_TREE)
+ return;
+
+ type = TYPE_P (t) ? t : TREE_TYPE (t);
+
+ /* Get the alias set from the expression or type (perhaps using a
+ front-end routine) and then copy bits from the type. */
+
+ /* It is incorrect to set RTX_UNCHANGING_P from TREE_READONLY (type)
+ here, because, in C and C++, the fact that a location is accessed
+ through a const expression does not mean that the value there can
+ never change. */
+ MEM_ALIAS_SET (ref) = get_alias_set (t);
+ MEM_VOLATILE_P (ref) = TYPE_VOLATILE (type);
+ MEM_IN_STRUCT_P (ref) = AGGREGATE_TYPE_P (type);
+
+ /* If we are making an object of this type, we know that it is a scalar if
+ the type is not an aggregate. */
+ if (objectp && ! AGGREGATE_TYPE_P (type))
+ MEM_SCALAR_P (ref) = 1;
+
+ /* If T is a type, this is all we can do. Otherwise, we may be able
+ to deduce some more information about the expression. */
+ if (TYPE_P (t))
+ return;
+
+ maybe_set_unchanging (ref, t);
+ if (TREE_THIS_VOLATILE (t))
+ MEM_VOLATILE_P (ref) = 1;
+
+ /* Now see if we can say more about whether it's an aggregate or
+ scalar. If we already know it's an aggregate, don't bother. */
+ if (MEM_IN_STRUCT_P (ref))
+ return;
+
+ /* Now remove any NOPs: they don't change what the underlying object is.
+ Likewise for SAVE_EXPR. */
+ while (TREE_CODE (t) == NOP_EXPR || TREE_CODE (t) == CONVERT_EXPR
+ || TREE_CODE (t) == NON_LVALUE_EXPR || TREE_CODE (t) == SAVE_EXPR)
+ t = TREE_OPERAND (t, 0);
+
+ /* Since we already know the type isn't an aggregate, if this is a decl,
+ it must be a scalar. Or if it is a reference into an aggregate,
+ this is part of an aggregate. Otherwise we don't know. */
+ if (DECL_P (t))
+ MEM_SCALAR_P (ref) = 1;
+ else if (TREE_CODE (t) == COMPONENT_REF || TREE_CODE (t) == ARRAY_REF
+ || TREE_CODE (t) == BIT_FIELD_REF)
+ MEM_IN_STRUCT_P (ref) = 1;
+}
+\f