Alex Coplan <alex.cop...@arm.com> writes:
> On 21/11/2023 16:49, Richard Sandiford wrote:
>> Richard Sandiford <richard.sandif...@arm.com> writes:
>> > Alex Coplan <alex.cop...@arm.com> writes:
>> >> This adds some helpers to access-utils.h for removing accesses from an
>> >> access_array. This is needed by the upcoming aarch64 load/store pair
>> >> fusion pass.
>> >>
>> >> Bootstrapped/regtested as a series on aarch64-linux-gnu, OK for trunk?
>> >>
>> >> gcc/ChangeLog:
>> >>
>> >> * rtl-ssa/access-utils.h (filter_accesses): New.
>> >> (remove_regno_access): New.
>> >> (check_remove_regno_access): New.
>> >> ---
>> >> gcc/rtl-ssa/access-utils.h | 42 ++++++++++++++++++++++++++++++++++++++
>> >> 1 file changed, 42 insertions(+)
>> >>
>> >> diff --git a/gcc/rtl-ssa/access-utils.h b/gcc/rtl-ssa/access-utils.h
>> >> index f078625babf..31259d742d9 100644
>> >> --- a/gcc/rtl-ssa/access-utils.h
>> >> +++ b/gcc/rtl-ssa/access-utils.h
>> >> @@ -78,6 +78,48 @@ drop_memory_access (T accesses)
>> >> return T (arr.begin (), accesses.size () - 1);
>> >> }
>> >>
>> >> +// Filter ACCESSES to return an access_array of only those accesses that
>> >> +// satisfy PREDICATE. Alocate the new array above WATERMARK.
>> >> +template<typename T, typename FilterPredicate>
>> >> +inline T
>> >> +filter_accesses (obstack_watermark &watermark,
>> >> + T accesses,
>> >> + FilterPredicate predicate)
>> >> +{
>> >> + access_array_builder builder (watermark);
>> >> + builder.reserve (accesses.size ());
>> >> + auto it = accesses.begin ();
>> >> + auto end = accesses.end ();
>> >> + for (; it != end; it++)
>> >> + if (predicate (*it))
>> >> + builder.quick_push (*it);
>> >
>> > It looks like the last five lines could be simplified to:
>> >
>> > for (access_info *access : accesses)
>> > if (!predicate (access))
>> > builder.quick_push (access);
>
> So I implemented these changes, but I found that I had to use auto
> instead of access_info * for the type of access in the for loop.
>
> That allows callers to use the most specific/derived type for the
> parameter in the predicate (e.g. use `use_info *` for an array of uses).
>
> Is it OK with that change? I've attached a revised patch.
> Bootstrapped/regtested on aarch64-linux-gnu.
OK, thanks.
Richard
> Thanks,
> Alex
>
>>
>> Oops, I meant:
>>
>> if (predicate (access))
>>
>> of course :)
>
> diff --git a/gcc/rtl-ssa/access-utils.h b/gcc/rtl-ssa/access-utils.h
> index f078625babf..9a62addfd2a 100644
> --- a/gcc/rtl-ssa/access-utils.h
> +++ b/gcc/rtl-ssa/access-utils.h
> @@ -78,6 +78,46 @@ drop_memory_access (T accesses)
> return T (arr.begin (), accesses.size () - 1);
> }
>
> +// Filter ACCESSES to return an access_array of only those accesses that
> +// satisfy PREDICATE. Alocate the new array above WATERMARK.
> +template<typename T, typename FilterPredicate>
> +inline T
> +filter_accesses (obstack_watermark &watermark,
> + T accesses,
> + FilterPredicate predicate)
> +{
> + access_array_builder builder (watermark);
> + builder.reserve (accesses.size ());
> + for (auto access : accesses)
> + if (predicate (access))
> + builder.quick_push (access);
> + return T (builder.finish ());
> +}
> +
> +// Given an array of ACCESSES, remove any access with regno REGNO.
> +// Allocate the new access array above WM.
> +template<typename T>
> +inline T
> +remove_regno_access (obstack_watermark &watermark,
> + T accesses, unsigned int regno)
> +{
> + using Access = decltype (accesses[0]);
> + auto pred = [regno](Access a) { return a->regno () != regno; };
> + return filter_accesses (watermark, accesses, pred);
> +}
> +
> +// As above, but additionally check that we actually did remove an access.
> +template<typename T>
> +inline T
> +check_remove_regno_access (obstack_watermark &watermark,
> + T accesses, unsigned regno)
> +{
> + auto orig_size = accesses.size ();
> + auto result = remove_regno_access (watermark, accesses, regno);
> + gcc_assert (result.size () < orig_size);
> + return result;
> +}
> +
> // If sorted array ACCESSES includes a reference to REGNO, return the
> // access, otherwise return null.
> template<typename T>
> diff --git a/gcc/rtl-ssa/accesses.cc b/gcc/rtl-ssa/accesses.cc
> index 76d70fd8bd3..9ec0e6be071 100644
> --- a/gcc/rtl-ssa/accesses.cc
> +++ b/gcc/rtl-ssa/accesses.cc
> @@ -1597,16 +1597,14 @@ access_array
> rtl_ssa::remove_note_accesses_base (obstack_watermark &watermark,
> access_array accesses)
> {
> + auto predicate = [](access_info *a) {
> + return !a->only_occurs_in_notes ();
> + };
> +
> for (access_info *access : accesses)
> if (access->only_occurs_in_notes ())
> - {
> - access_array_builder builder (watermark);
> - builder.reserve (accesses.size ());
> - for (access_info *access2 : accesses)
> - if (!access2->only_occurs_in_notes ())
> - builder.quick_push (access2);
> - return builder.finish ();
> - }
> + return filter_accesses (watermark, accesses, predicate);
> +
> return accesses;
> }
>
