On Sat, Jul 15, 2023 at 5:21 AM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> This adds flow_sensitive_info_storage and uses it in
> maybe_fold_comparisons_from_match_pd as mentioned in
> https://gcc.gnu.org/pipermail/gcc-patches/2023-June/621817.html .
> Since using it in maybe_fold_comparisons_from_match_pd was easy
> and allowed me to test the storage earlier, I did it.
>
> This also hides better how the flow sensitive information is
> stored and only a single place needs to be updated if that
> ever changes (again).
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
OK.
Thanks for doing this!
Richard.
> gcc/ChangeLog:
>
> * gimple-fold.cc (fosa_unwind): Replace `vrange_storage *`
> with flow_sensitive_info_storage.
> (follow_outer_ssa_edges): Update how to save off the flow
> sensitive info.
> (maybe_fold_comparisons_from_match_pd): Update restoring
> of flow sensitive info.
> * tree-ssanames.cc (flow_sensitive_info_storage::save): New method.
> (flow_sensitive_info_storage::restore): New method.
> (flow_sensitive_info_storage::save_and_clear): New method.
> (flow_sensitive_info_storage::clear_storage): New method.
> * tree-ssanames.h (class flow_sensitive_info_storage): New class.
> ---
> gcc/gimple-fold.cc | 17 +++++------
> gcc/tree-ssanames.cc | 72 ++++++++++++++++++++++++++++++++++++++++++++
> gcc/tree-ssanames.h | 21 +++++++++++++
> 3 files changed, 100 insertions(+), 10 deletions(-)
>
> diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
> index 4027ff71e10..de94efbcff7 100644
> --- a/gcc/gimple-fold.cc
> +++ b/gcc/gimple-fold.cc
> @@ -6947,7 +6947,7 @@ and_comparisons_1 (tree type, enum tree_code code1,
> tree op1a, tree op1b,
> }
>
> static basic_block fosa_bb;
> -static vec<std::pair<tree, vrange_storage *> > *fosa_unwind;
> +static vec<std::pair<tree, flow_sensitive_info_storage> > *fosa_unwind;
> static tree
> follow_outer_ssa_edges (tree val)
> {
> @@ -6967,14 +6967,11 @@ follow_outer_ssa_edges (tree val)
> || POINTER_TYPE_P (TREE_TYPE (val)))
> && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (val)))
> return NULL_TREE;
> + flow_sensitive_info_storage storage;
> + storage.save_and_clear (val);
> /* If the definition does not dominate fosa_bb temporarily reset
> flow-sensitive info. */
> - if (val->ssa_name.info.range_info)
> - {
> - fosa_unwind->safe_push (std::make_pair
> - (val, val->ssa_name.info.range_info));
> - val->ssa_name.info.range_info = NULL;
> - }
> + fosa_unwind->safe_push (std::make_pair (val, storage));
> return val;
> }
> return val;
> @@ -7034,14 +7031,14 @@ maybe_fold_comparisons_from_match_pd (tree type, enum
> tree_code code,
> type, gimple_assign_lhs (stmt1),
> gimple_assign_lhs (stmt2));
> fosa_bb = outer_cond_bb;
> - auto_vec<std::pair<tree, vrange_storage *>, 8> unwind_stack;
> + auto_vec<std::pair<tree, flow_sensitive_info_storage>, 8> unwind_stack;
> fosa_unwind = &unwind_stack;
> if (op.resimplify (NULL, (!outer_cond_bb
> ? follow_all_ssa_edges : follow_outer_ssa_edges)))
> {
> fosa_unwind = NULL;
> for (auto p : unwind_stack)
> - p.first->ssa_name.info.range_info = p.second;
> + p.second.restore (p.first);
> if (gimple_simplified_result_is_gimple_val (&op))
> {
> tree res = op.ops[0];
> @@ -7065,7 +7062,7 @@ maybe_fold_comparisons_from_match_pd (tree type, enum
> tree_code code,
> }
> fosa_unwind = NULL;
> for (auto p : unwind_stack)
> - p.first->ssa_name.info.range_info = p.second;
> + p.second.restore (p.first);
>
> return NULL_TREE;
> }
> diff --git a/gcc/tree-ssanames.cc b/gcc/tree-ssanames.cc
> index 5fdb6a37e9f..f81332451fc 100644
> --- a/gcc/tree-ssanames.cc
> +++ b/gcc/tree-ssanames.cc
> @@ -916,3 +916,75 @@ make_pass_release_ssa_names (gcc::context *ctxt)
> {
> return new pass_release_ssa_names (ctxt);
> }
> +
> +/* Save and restore of flow sensitive information. */
> +
> +/* Save off the flow sensitive info from NAME. */
> +
> +void
> +flow_sensitive_info_storage::save (tree name)
> +{
> + gcc_assert (state == 0);
> + if (!POINTER_TYPE_P (TREE_TYPE (name)))
> + {
> + range_info = SSA_NAME_RANGE_INFO (name);
> + state = 1;
> + return;
> + }
> + state = -1;
> + auto ptr_info = SSA_NAME_PTR_INFO (name);
> + if (ptr_info)
> + {
> + align = ptr_info->align;
> + misalign = ptr_info->misalign;
> + null = SSA_NAME_PTR_INFO (name)->pt.null;
> + }
> + else
> + {
> + align = 0;
> + misalign = 0;
> + null = true;
> + }
> +}
> +
> +/* Restore the flow sensitive info from NAME. */
> +
> +void
> +flow_sensitive_info_storage::restore (tree name)
> +{
> + gcc_assert (state != 0);
> + if (!POINTER_TYPE_P (TREE_TYPE (name)))
> + {
> + gcc_assert (state == 1);
> + SSA_NAME_RANGE_INFO (name) = range_info;
> + return;
> + }
> + gcc_assert (state == -1);
> + auto ptr_info = SSA_NAME_PTR_INFO (name);
> + /* If there was no flow sensitive info on the pointer
> + just return, there is nothing to restore to. */
> + if (!ptr_info)
> + return;
> + if (align != 0)
> + set_ptr_info_alignment (ptr_info, align, misalign);
> + else
> + mark_ptr_info_alignment_unknown (ptr_info);
> + SSA_NAME_PTR_INFO (name)->pt.null = null;
> +}
> +
> +/* Save off the flow sensitive info from NAME.
> + And reset the flow sensitive info of NAME. */
> +
> +void
> +flow_sensitive_info_storage::save_and_clear (tree name)
> +{
> + save (name);
> + reset_flow_sensitive_info (name);
> +}
> +
> +/* Clear the storage. */
> +void
> +flow_sensitive_info_storage::clear_storage (void)
> +{
> + state = 0;
> +}
> diff --git a/gcc/tree-ssanames.h b/gcc/tree-ssanames.h
> index f3fa609208a..98f4a835483 100644
> --- a/gcc/tree-ssanames.h
> +++ b/gcc/tree-ssanames.h
> @@ -136,5 +136,26 @@ make_temp_ssa_name (tree type, gimple *stmt, const char
> *name)
> return ssa_name;
> }
>
> +/* A class which is used to save/restore the flow sensitive information. */
> +class flow_sensitive_info_storage
> +{
> +public:
> + void save (tree);
> + void save_and_clear (tree);
> + void restore (tree);
> + void clear_storage ();
> +private:
> + /* 0 means there is nothing saved.
> + 1 means non pointer is saved.
> + -1 means a pointer type is saved.
> + -2 means a pointer type is saved but no information was saved. */
> + int state = 0;
> + /* The range info for non pointers */
> + vrange_storage *range_info = nullptr;
> + /* Flow sensitive pointer information. */
> + unsigned int align = 0;
> + unsigned int misalign = 0;
> + bool null = true;
> +};
>
> #endif /* GCC_TREE_SSANAMES_H */
> --
> 2.31.1
>
