On Wed, May 14, 2025 at 5:01 PM Andrew Pinski <quic_apin...@quicinc.com> wrote:
>
> As sugguested in
> https://gcc.gnu.org/pipermail/gcc-patches/2025-April/681507.html,
> this adds the aliasing walk limit.
OK for both.
Thanks,
Richard.
> gcc/ChangeLog:
>
> * tree-ssa-forwprop.cc (optimize_memcpy_to_memset): Add a limit on
> the alias walk.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/tree-ssa-forwprop.cc | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
> index 71de99f46ff..0f52e8fe6ef 100644
> --- a/gcc/tree-ssa-forwprop.cc
> +++ b/gcc/tree-ssa-forwprop.cc
> @@ -1216,13 +1216,15 @@ optimize_memcpy_to_memset (gimple_stmt_iterator
> *gsip, tree dest, tree src, tree
> ao_ref_init (&read, src);
> tree vuse = gimple_vuse (stmt);
> gimple *defstmt;
> + unsigned limit = param_sccvn_max_alias_queries_per_access;
> do {
> if (vuse == NULL || TREE_CODE (vuse) != SSA_NAME)
> return false;
> defstmt = SSA_NAME_DEF_STMT (vuse);
> if (is_a <gphi*>(defstmt))
> return false;
> -
> + if (limit-- == 0)
> + return false;
> /* If the len was null, then we can use TBBA. */
> if (stmt_may_clobber_ref_p_1 (defstmt, &read,
> /* tbaa_p = */ len_was_null))
> --
> 2.43.0
>
