On Fri, Nov 17, 2017 at 5:17 AM, Jeff Law <[email protected]> wrote:
> No nyquil tonight, so the proper patch is attached this time...
>
> --
>
>
>
> So the next group of changes is focused on breaking down evrp into an
> analysis engine and the actual optimization pass. The analysis engine
> can be embedded into other dom walker passes quite easily. I've done it
> for the sprintf warnings as well as the main DOM optimizer locally.
>
> Separating analysis from optimization for edge ranges and PHI ranges is
> easy. Doing so for statements isn't terribly hard either, but does
> require a tiny bit of refactoring elsewhere.
>
> Which brings us to this patch.
>
> If we look at evrp_dom_walker::before_dom_children we'll see this in the
> statement processing code:
>
> else if (stmt_interesting_for_vrp (stmt))
> {
> edge taken_edge;
> value_range vr = VR_INITIALIZER;
> extract_range_from_stmt (stmt, &taken_edge, &output, &vr);
> if (output
> && (vr.type == VR_RANGE || vr.type == VR_ANTI_RANGE))
> {
> update_value_range (output, &vr);
> vr = *get_value_range (output);
>
> /* Mark stmts whose output we fully propagate for removal. */
>
> etc.
>
> Conceptually this fragment is part of the analysis side. But the
> subsequent code (optimization side) wants to know the "output" of the
> statement. I'm not keen on calling extract_range_from_stmt on both the
> analysis side and the optimization side.
>
> So this patch factors out a bit of extract_range_from_stmt and its child
> vrp_visit_assignment_or_call into a routine that will return the proper
> SSA_NAME. So the analysis side calls extract_range_from_stmt and the
> optimization side calls the new "get_output_for_vrp".
>
> And of course to avoid duplication we use get_output_for_vrp from within
> vrp_visit_assignment_or_call.
>
>
> Bootstrapped and regression tested on x86_64. OK for the trunk?
Ok.
Richard.
> Jeff
>
>
> * vr-values.h (get_output_for_vrp): Prototype.
> * vr-values.c (get_output_for_vrp): New function extracted from
> vrp_visit_assignment_or_call and extract_range_from_stmt.
> (vrp_visit_assignment_or_call): Use get_output_for_vrp. Simplify.
>
> diff --git a/gcc/vr-values.c b/gcc/vr-values.c
> index d4434de..3e760a3 100644
> --- a/gcc/vr-values.c
> +++ b/gcc/vr-values.c
> @@ -1955,19 +1955,18 @@ vrp_valueize_1 (tree name)
> }
> return name;
> }
> -/* Visit assignment STMT. If it produces an interesting range, record
> - the range in VR and set LHS to OUTPUT_P. */
>
> -void
> -vr_values::vrp_visit_assignment_or_call (gimple *stmt, tree *output_p,
> - value_range *vr)
> +/* Given STMT, an assignment or call, return its LHS if the type
> + of the LHS is suitable for VRP analysis, else return NULL_TREE. */
> +
> +tree
> +get_output_for_vrp (gimple *stmt)
> {
> - tree lhs;
> - enum gimple_code code = gimple_code (stmt);
> - lhs = gimple_get_lhs (stmt);
> - *output_p = NULL_TREE;
> + if (!is_gimple_assign (stmt) && !is_gimple_call (stmt))
> + return NULL_TREE;
>
> /* We only keep track of ranges in integral and pointer types. */
> + tree lhs = gimple_get_lhs (stmt);
> if (TREE_CODE (lhs) == SSA_NAME
> && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
> /* It is valid to have NULL MIN/MAX values on a type. See
> @@ -1975,8 +1974,25 @@ vr_values::vrp_visit_assignment_or_call (gimple *stmt,
> tree *output_p,
> && TYPE_MIN_VALUE (TREE_TYPE (lhs))
> && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
> || POINTER_TYPE_P (TREE_TYPE (lhs))))
> + return lhs;
> +
> + return NULL_TREE;
> +}
> +
> +/* Visit assignment STMT. If it produces an interesting range, record
> + the range in VR and set LHS to OUTPUT_P. */
> +
> +void
> +vr_values::vrp_visit_assignment_or_call (gimple *stmt, tree *output_p,
> + value_range *vr)
> +{
> + tree lhs = get_output_for_vrp (stmt);
> + *output_p = lhs;
> +
> + /* We only keep track of ranges in integral and pointer types. */
> + if (lhs)
> {
> - *output_p = lhs;
> + enum gimple_code code = gimple_code (stmt);
>
> /* Try folding the statement to a constant first. */
> x_vr_values = this;
> diff --git a/gcc/vr-values.h b/gcc/vr-values.h
> index 20bd6c5..24f013a 100644
> --- a/gcc/vr-values.h
> +++ b/gcc/vr-values.h
> @@ -118,4 +118,5 @@ class vr_values
>
> #define VR_INITIALIZER { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }
>
> +extern tree get_output_for_vrp (gimple *);
> #endif /* GCC_VR_VALUES_H */
>
