> Am 22.07.2025 um 17:05 schrieb Martin Jambor <mjam...@suse.cz>:
>
> Hi,
>
> we currently use the types encountered in the function body and not in
> type declaration to perform total scalarization. Bug PR 119085
> uncovered that we miss a check that when the same data is accessed
> with aggregate types that those are actually compatible. Without it,
> we can base total scalarization on a type that does not "cover" all
> live data in a different part of the function. This patch adds the
> check.
>
> Bootstrapped and tested on x86_64-linux. OK for master and all active
> release branches?
Ok
Richard
> Thanks,
>
> Martin
>
>
> gcc/ChangeLog:
>
> 2025-07-21 Martin Jambor <mjam...@suse.cz>
>
> PR tree-optimization/119085
> * tree-sra.cc (sort_and_splice_var_accesses): Prevent total
> scalarization if two incompatible aggregates access the same place.
>
> gcc/testsuite/ChangeLog:
>
> 2025-07-21 Martin Jambor <mjam...@suse.cz>
>
> PR tree-optimization/119085
> * gcc.dg/tree-ssa/pr119085.c: New test.
> ---
> gcc/testsuite/gcc.dg/tree-ssa/pr119085.c | 37 ++++++++++++++++++++++++
> gcc/tree-sra.cc | 6 ++++
> 2 files changed, 43 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr119085.c
>
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr119085.c
> b/gcc/testsuite/gcc.dg/tree-ssa/pr119085.c
> new file mode 100644
> index 00000000000..e9811ce12b5
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr119085.c
> @@ -0,0 +1,37 @@
> +/* { dg-do run } */
> +/* { dg-options "-O1" } */
> +
> +struct with_hole {
> + int x;
> + long y;
> +};
> +struct without_hole {
> + int x;
> + int y;
> +};
> +union u {
> + struct with_hole with_hole;
> + struct without_hole without_hole;
> +};
> +
> +void __attribute__((noinline))
> +test (union u *up, union u u)
> +{
> + union u u2;
> + volatile int f = 0;
> + u2 = u;
> + if (f)
> + u2.with_hole = u.with_hole;
> + *up = u2;
> +}
> +
> +int main(void)
> +{
> + union u u;
> + union u u2;
> + u2.without_hole.y = -1;
> + test (&u, u2);
> + if (u.without_hole.y != -1)
> + __builtin_abort ();
> + return 0;
> +}
> diff --git a/gcc/tree-sra.cc b/gcc/tree-sra.cc
> index 240af676ea3..032f2770484 100644
> --- a/gcc/tree-sra.cc
> +++ b/gcc/tree-sra.cc
> @@ -2504,6 +2504,12 @@ sort_and_splice_var_accesses (tree var)
> }
> unscalarizable_region = true;
> }
> + /* If there the same place is accessed with two incompatible
> + aggregate types, trying to base total scalarization on either of
> + them can be wrong. */
> + if (!first_scalar && !types_compatible_p (access->type, ac2->type))
> + bitmap_set_bit (cannot_scalarize_away_bitmap,
> + DECL_UID (access->base));
>
> if (grp_same_access_path
> && (!ac2->grp_same_access_path
> --
> 2.50.1
>
