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| author | Jakub Jelinek <jakub@redhat.com> | 2024-01-23 09:02:48 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2024-01-23 09:05:05 +0100 |
| commit | 5015015ae6b29b3f1734c7693ba25b88cdd531a1 (patch) | |
| tree | d6081fad756e67ff631cbcf814ac19e85b2a0a5b | |
| parent | f12317306ee714aed0ca7ed01cafa520296b4c4c (diff) | |
| download | gcc-5015015ae6b29b3f1734c7693ba25b88cdd531a1.zip gcc-5015015ae6b29b3f1734c7693ba25b88cdd531a1.tar.gz gcc-5015015ae6b29b3f1734c7693ba25b88cdd531a1.tar.bz2 | |
fold-const: Fold larger VIEW_CONVERT_EXPRs [PR113462]
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.
This patch fixes even that by using a XALLOCAVEC allocated buffer
if the type size is 129 .. 8192 bytes.
2024-01-22 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/113462
* fold-const.cc (native_interpret_int): Don't punt if total_bytes
is larger than HOST_BITS_PER_DOUBLE_INT / BITS_PER_UNIT.
(fold_view_convert_expr): Use XALLOCAVEC buffers for types with
sizes between 129 and 8192 bytes.
| -rw-r--r-- | gcc/fold-const.cc | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc index 385e4a6..1fd9572 100644 --- a/gcc/fold-const.cc +++ b/gcc/fold-const.cc @@ -8773,8 +8773,7 @@ native_interpret_int (tree type, const unsigned char *ptr, int len) else total_bytes = GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (type)); - if (total_bytes > len - || total_bytes * BITS_PER_UNIT > HOST_BITS_PER_DOUBLE_INT) + if (total_bytes > len) return NULL_TREE; wide_int result = wi::from_buffer (ptr, total_bytes); @@ -9329,9 +9328,10 @@ fold_view_convert_vector_encoding (tree type, tree expr) static tree fold_view_convert_expr (tree type, tree expr) { - /* We support up to 1024-bit values (for GCN/RISC-V V128QImode). */ unsigned char buffer[128]; + unsigned char *buf; int len; + HOST_WIDE_INT l; /* Check that the host and target are sane. */ if (CHAR_BIT != 8 || BITS_PER_UNIT != 8) @@ -9341,11 +9341,23 @@ fold_view_convert_expr (tree type, tree expr) if (tree res = fold_view_convert_vector_encoding (type, expr)) return res; - len = native_encode_expr (expr, buffer, sizeof (buffer)); + l = int_size_in_bytes (type); + if (l > (int) sizeof (buffer) + && l <= WIDE_INT_MAX_PRECISION / BITS_PER_UNIT) + { + buf = XALLOCAVEC (unsigned char, l); + len = l; + } + else + { + buf = buffer; + len = sizeof (buffer); + } + len = native_encode_expr (expr, buf, len); if (len == 0) return NULL_TREE; - return native_interpret_expr (type, buffer, len); + return native_interpret_expr (type, buf, len); } /* Build an expression for the address of T. Folds away INDIRECT_REF |