On Mon, Jan 22, 2024 at 11:27:52AM +0100, Richard Biener wrote:
> We run into
>
> static tree
> native_interpret_int (tree type, const unsigned char *ptr, int len)
> {
> ...
> if (total_bytes > len
> || total_bytes * BITS_PER_UNIT > HOST_BITS_PER_DOUBLE_INT)
> return NULL_TREE;
>
> OTOH using a V_C_E to "truncate" a _BitInt looks wrong? OTOH the
> check doesn't really handle native_encode_expr using the "proper"
> wide_int encoding however that's exactly handled. So it might be
> a pre-existing issue that's only uncovered by large _BitInts
> (__int128 might show similar issues?)
I guess the || total_bytes * BITS_PER_UNIT > HOST_BITS_PER_DOUBLE_INT
conditions make no sense, all we care is whether it fits in the buffer
or not.
But then there is
fold_view_convert_expr
(and other spots) which use
/* We support up to 1024-bit values (for GCN/RISC-V V128QImode). */
unsigned char buffer[128];
or something similar.
Perhaps we could use XALLOCAVEC there instead (or use it only for the
larger sizes and keep the static buffer for the common case).
Jakub
