+/* Update *ARG which is defined in STMT so that it contains the
+ computed value if that seems profitable. Return true if the
+ statement is made dead by that rewriting. */
+
+static bool
+jump_function_from_stmt (tree *arg, gimple stmt)
+{
+ enum tree_code code = gimple_assign_rhs_code (stmt);
+ if (code == ADDR_EXPR)
+ {
+ /* For arg = &p->i transform it to p, if possible. */
+ tree rhs1 = gimple_assign_rhs1 (stmt);
+ HOST_WIDE_INT offset;
+ tree tem = get_addr_base_and_unit_offset (TREE_OPERAND (rhs1, 0),
+ &offset);
+ if (tem
+ && TREE_CODE (tem) == MEM_REF
+ && double_int_zero_p
+ (double_int_add (mem_ref_offset (tem),
+ shwi_to_double_int (offset))))
+ {
+ *arg = TREE_OPERAND (tem, 0);
+ return true;
+ }
+ }
+ /* TODO: Much like IPA-CP jump-functions we want to handle constant
+ additions symbolically here, and we'd need to update the comparison
+ code that compares the arg + cst tuples in our caller. For now the
+ code above exactly handles the VEC_BASE pattern from vec.h. */
+ return false;
+}
+