+2003-07-02 Eric Botcazou <ebotcazou@libertysurf.fr>
+
+ PR optimization/11210
+ * expr.c (handled_component_p) [NOP_EXPR]: Add ??? note
+ about the behaviour with regard to bitfields.
+ * fold-const (decode_field_reference): Record outermost type in
+ case the expression is a NOP. Strip all NOPs. Set the signedness
+ to that of the outermost type (if any) when the bitsize is equal
+ to the size of the type.
+
2003-07-02 Richard Sandiford <rsandifo@redhat.com>
* config/mips/mips.md (addsi3): Remove workaround for adds of -32768.
case VIEW_CONVERT_EXPR:
return 1;
+ /* ??? Sure they are handled, but get_inner_reference may return
+ a different PBITSIZE, depending upon whether the expression is
+ wrapped up in a NOP_EXPR or not, e.g. for bitfields. */
case NOP_EXPR:
case CONVERT_EXPR:
return (TYPE_MODE (TREE_TYPE (t))
enum machine_mode *pmode, int *punsignedp, int *pvolatilep,
tree *pmask, tree *pand_mask)
{
+ tree outer_type = 0;
tree and_mask = 0;
tree mask, inner, offset;
tree unsigned_type;
if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
return 0;
+ /* We are interested in the bare arrangement of bits, so strip everything
+ that doesn't affect the machine mode. However, record the type of the
+ outermost expression if it may matter below. */
+ if (TREE_CODE (exp) == NOP_EXPR
+ || TREE_CODE (exp) == CONVERT_EXPR
+ || TREE_CODE (exp) == NON_LVALUE_EXPR)
+ outer_type = TREE_TYPE (exp);
STRIP_NOPS (exp);
if (TREE_CODE (exp) == BIT_AND_EXPR)
|| TREE_CODE (inner) == PLACEHOLDER_EXPR)
return 0;
+ /* If the number of bits in the reference is the same as the bitsize of
+ the outer type, then the outer type gives the signedness. Otherwise
+ (in case of a small bitfield) the signedness is unchanged. */
+ if (outer_type && *pbitsize == tree_low_cst (TYPE_SIZE (outer_type), 1))
+ *punsignedp = TREE_UNSIGNED (outer_type);
+
/* Compute the mask to access the bitfield. */
unsigned_type = (*lang_hooks.types.type_for_size) (*pbitsize, 1);
precision = TYPE_PRECISION (unsigned_type);