+2006-02-10 Richard Guenther <rguenther@suse.de>
+
+ * tree-dfa.c (get_ref_base_and_extent): When computing maxsize
+ deal with structures that end in implicitly variable sized arrays.
+
2006-02-09 Zdenek Dvorak <dvorakz@suse.cz>
PR rtl-optimization/24762
HOST_WIDE_INT maxsize = -1;
tree size_tree = NULL_TREE;
tree bit_offset = bitsize_zero_node;
+ bool seen_variable_array_ref = false;
gcc_assert (!SSA_VAR_P (exp));
fold_convert (bitsizetype, index),
bitsize_unit_node);
bit_offset = size_binop (PLUS_EXPR, bit_offset, index);
+
+ /* An array ref with a constant index up in the structure
+ hierarchy will constrain the size of any variable array ref
+ lower in the access hierarchy. */
+ seen_variable_array_ref = false;
}
else
{
}
else
maxsize = -1;
+
+ /* Remember that we have seen an array ref with a variable
+ index. */
+ seen_variable_array_ref = true;
}
}
break;
}
done:
+ /* We need to deal with variable arrays ending structures such as
+ struct { int length; int a[1]; } x; x.a[d]
+ struct { struct { int a; int b; } a[1]; } x; x.a[d].a
+ struct { struct { int a[1]; } a[1]; } x; x.a[0][d], x.a[d][0]
+ where we do not know maxsize for variable index accesses to
+ the array. The simplest way to conservatively deal with this
+ is to punt in the case that offset + maxsize reaches the
+ base type boundary. */
+ if (seen_variable_array_ref
+ && maxsize != -1
+ && host_integerp (TYPE_SIZE (TREE_TYPE (exp)), 1)
+ && TREE_INT_CST_LOW (bit_offset) + maxsize
+ == TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (exp))))
+ maxsize = -1;
+
/* ??? Due to negative offsets in ARRAY_REF we can end up with
negative bit_offset here. We might want to store a zero offset
in this case. */