+ tree sym;
+
+ while (handled_component_p (*tp))
+ tp = &TREE_OPERAND (*tp, 0);
+ if (TREE_CODE (*tp) == MEM_REF
+ && TREE_CODE (TREE_OPERAND (*tp, 0)) == ADDR_EXPR
+ && (sym = TREE_OPERAND (TREE_OPERAND (*tp, 0), 0))
+ && DECL_P (sym)
+ && !TREE_ADDRESSABLE (sym)
+ && symbol_marked_for_renaming (sym))
+ {
+ if (TREE_CODE (TREE_TYPE (sym)) == VECTOR_TYPE
+ && useless_type_conversion_p (TREE_TYPE (*tp),
+ TREE_TYPE (TREE_TYPE (sym)))
+ && multiple_of_p (sizetype, TREE_OPERAND (*tp, 1),
+ TYPE_SIZE_UNIT (TREE_TYPE (*tp))))
+ {
+ *tp = build3 (BIT_FIELD_REF, TREE_TYPE (*tp), sym,
+ TYPE_SIZE (TREE_TYPE (*tp)),
+ int_const_binop (MULT_EXPR,
+ bitsize_int (BITS_PER_UNIT),
+ TREE_OPERAND (*tp, 1)));
+ }
+ else if (TREE_CODE (TREE_TYPE (sym)) == COMPLEX_TYPE
+ && useless_type_conversion_p (TREE_TYPE (*tp),
+ TREE_TYPE (TREE_TYPE (sym))))
+ {
+ *tp = build1 (integer_zerop (TREE_OPERAND (*tp, 1))
+ ? REALPART_EXPR : IMAGPART_EXPR,
+ TREE_TYPE (*tp), sym);
+ }
+ else if (integer_zerop (TREE_OPERAND (*tp, 1)))
+ {
+ if (!useless_type_conversion_p (TREE_TYPE (*tp),
+ TREE_TYPE (sym)))
+ *tp = build1 (VIEW_CONVERT_EXPR,
+ TREE_TYPE (*tp), sym);
+ else
+ *tp = sym;
+ }
+ }
+}
+
+/* For a tree REF return its base if it is the base of a MEM_REF
+ that cannot be rewritten into SSA form. Otherwise return NULL_TREE. */
+
+static tree
+non_rewritable_mem_ref_base (tree ref)
+{
+ tree base = ref;
+
+ /* A plain decl does not need it set. */
+ if (DECL_P (ref))
+ return NULL_TREE;
+
+ while (handled_component_p (base))
+ base = TREE_OPERAND (base, 0);
+
+ /* But watch out for MEM_REFs we cannot lower to a
+ VIEW_CONVERT_EXPR or a BIT_FIELD_REF. */
+ if (TREE_CODE (base) == MEM_REF
+ && TREE_CODE (TREE_OPERAND (base, 0)) == ADDR_EXPR)
+ {
+ tree decl = TREE_OPERAND (TREE_OPERAND (base, 0), 0);
+ if ((TREE_CODE (TREE_TYPE (decl)) == VECTOR_TYPE
+ || TREE_CODE (TREE_TYPE (decl)) == COMPLEX_TYPE)
+ && useless_type_conversion_p (TREE_TYPE (base),
+ TREE_TYPE (TREE_TYPE (decl)))
+ && double_int_fits_in_uhwi_p (mem_ref_offset (base))
+ && double_int_ucmp
+ (tree_to_double_int (TYPE_SIZE_UNIT (TREE_TYPE (decl))),
+ mem_ref_offset (base)) == 1
+ && multiple_of_p (sizetype, TREE_OPERAND (base, 1),
+ TYPE_SIZE_UNIT (TREE_TYPE (base))))
+ return NULL_TREE;
+ if (DECL_P (decl)
+ && (!integer_zerop (TREE_OPERAND (base, 1))
+ || (DECL_SIZE (decl)
+ != TYPE_SIZE (TREE_TYPE (base)))
+ || TREE_THIS_VOLATILE (decl) != TREE_THIS_VOLATILE (base)))
+ return decl;
+ }
+
+ return NULL_TREE;
+}
+
+/* For an lvalue tree LHS return true if it cannot be rewritten into SSA form.
+ Otherwise return true. */
+
+static bool
+non_rewritable_lvalue_p (tree lhs)
+{
+ /* A plain decl is always rewritable. */
+ if (DECL_P (lhs))
+ return false;
+
+ /* A decl that is wrapped inside a MEM-REF that covers
+ it full is also rewritable.
+ ??? The following could be relaxed allowing component
+ references that do not change the access size. */
+ if (TREE_CODE (lhs) == MEM_REF
+ && TREE_CODE (TREE_OPERAND (lhs, 0)) == ADDR_EXPR
+ && integer_zerop (TREE_OPERAND (lhs, 1)))
+ {
+ tree decl = TREE_OPERAND (TREE_OPERAND (lhs, 0), 0);
+ if (DECL_P (decl)
+ && DECL_SIZE (decl) == TYPE_SIZE (TREE_TYPE (lhs))
+ && (TREE_THIS_VOLATILE (decl) == TREE_THIS_VOLATILE (lhs)))
+ return false;
+ }
+
+ return true;
+}
+
+/* When possible, clear TREE_ADDRESSABLE bit or set DECL_GIMPLE_REG_P bit and
+ mark the variable VAR for conversion into SSA. Return true when updating
+ stmts is required. */
+
+static bool
+maybe_optimize_var (tree var, bitmap addresses_taken, bitmap not_reg_needs)
+{
+ bool update_vops = false;
+
+ /* Global Variables, result decls cannot be changed. */
+ if (is_global_var (var)
+ || TREE_CODE (var) == RESULT_DECL
+ || bitmap_bit_p (addresses_taken, DECL_UID (var)))
+ return false;
+
+ /* If the variable is not in the list of referenced vars then we
+ do not need to touch it nor can we rename it. */
+ if (!referenced_var_lookup (cfun, DECL_UID (var)))
+ return false;
+
+ if (TREE_ADDRESSABLE (var)
+ /* Do not change TREE_ADDRESSABLE if we need to preserve var as
+ a non-register. Otherwise we are confused and forget to
+ add virtual operands for it. */
+ && (!is_gimple_reg_type (TREE_TYPE (var))
+ || TREE_CODE (TREE_TYPE (var)) == VECTOR_TYPE
+ || TREE_CODE (TREE_TYPE (var)) == COMPLEX_TYPE
+ || !bitmap_bit_p (not_reg_needs, DECL_UID (var))))
+ {
+ TREE_ADDRESSABLE (var) = 0;
+ if (is_gimple_reg (var))
+ mark_sym_for_renaming (var);
+ update_vops = true;
+ if (dump_file)
+ {
+ fprintf (dump_file, "No longer having address taken: ");
+ print_generic_expr (dump_file, var, 0);
+ fprintf (dump_file, "\n");
+ }
+ }
+
+ if (!DECL_GIMPLE_REG_P (var)
+ && !bitmap_bit_p (not_reg_needs, DECL_UID (var))
+ && (TREE_CODE (TREE_TYPE (var)) == COMPLEX_TYPE
+ || TREE_CODE (TREE_TYPE (var)) == VECTOR_TYPE)
+ && !TREE_THIS_VOLATILE (var)
+ && (TREE_CODE (var) != VAR_DECL || !DECL_HARD_REGISTER (var)))
+ {
+ DECL_GIMPLE_REG_P (var) = 1;
+ mark_sym_for_renaming (var);
+ update_vops = true;
+ if (dump_file)
+ {
+ fprintf (dump_file, "Now a gimple register: ");
+ print_generic_expr (dump_file, var, 0);
+ fprintf (dump_file, "\n");
+ }
+ }
+
+ return update_vops;
+}
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