On Fri, 5 Sept 2025 at 13:54, Richard Biener <rguent...@suse.de> wrote:
>
> The PR reports
>
> vectorizer.h:276:3: runtime error: load of value 32695, which is not a valid
> value for type 'internal_fn'
>
> which I believe is from
>
> slp_node->data = new vect_load_store_data (std::move (ls));
>
> where 'ls' can be partly uninitialized (and that data will be not
> used, but of course the move CTOR doesn't know this). The following
> tries to fix that by using value-initialization of 'ls'.
>
> Bootstrap and regtest running on x86_64-unknown-linux-gnu.
>
> Using ls() failed (somehow that got a function type?),
Yes, 'x y();' is a local declaration of a function that returns 'x',
that syntax comes from C.
> I hope {} is C++14.
Yes, that's valid since C++11, and cannot be parsed as a function.
> I also hope {} will value-initialize a union member in
> the same way a defaulted move CTOR will access it.
Yes, that should work fine. You could also just add a user-provided
default constructor to vect_load_store_data so that it's always
properly initialized, or at least add a default-initializer to the one
member to ensure it's valid:
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -280,7 +280,7 @@ struct vect_load_store_data : vect_data {
vect_memory_access_type memory_access_type;
dr_alignment_support alignment_support_scheme;
int misalignment;
- internal_fn lanes_ifn; // VMAT_LOAD_STORE_LANES
+ internal_fn lanes_ifn{}; // VMAT_LOAD_STORE_LANES
poly_int64 poffset;
union {
internal_fn ifn; // VMAT_GATHER_SCATTER_IFN
>
> PR tree-optimization/121703
> * tree-vect-stmts.cc (vectorizable_store): Value-initialize ls.
> (vectorizable_load): Likewise.
> ---
> gcc/tree-vect-stmts.cc | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
> index 9fcc2fd0849..7eabf169a2b 100644
> --- a/gcc/tree-vect-stmts.cc
> +++ b/gcc/tree-vect-stmts.cc
> @@ -7881,7 +7881,7 @@ vectorizable_store (vec_info *vinfo,
> if (!STMT_VINFO_DATA_REF (stmt_info))
> return false;
>
> - vect_load_store_data _ls_data;
> + vect_load_store_data _ls_data{};
> vect_load_store_data &ls = slp_node->get_data (_ls_data);
> if (cost_vec
> && !get_load_store_type (vinfo, stmt_info, vectype, slp_node,
> mask_node,
> @@ -9451,7 +9451,7 @@ vectorizable_load (vec_info *vinfo,
> else
> group_size = 1;
>
> - vect_load_store_data _ls_data;
> + vect_load_store_data _ls_data{};
> vect_load_store_data &ls = slp_node->get_data (_ls_data);
> if (cost_vec
> && !get_load_store_type (vinfo, stmt_info, vectype, slp_node,
> mask_node,
> --
> 2.51.0
>
