Commit Graph

8 Commits

Author SHA1 Message Date
Roman Gareev 113fa82c3c [Polly] Check the properties of accesses to operands of a matrix-matrix
multiplication

The following code modifies elements of the array D.

    for (i = 0; i < _PB_NI; i++)
      for (j = 0; j < _PB_NJ; j++)
      {
        for (k = 0; k < _PB_NK; k++)
        {
          double Mul = A[i][k] * B[k][j];
          D[i][j][k] += Mul;
          C[i][j] += Mul;
        }
      }

Nevertheless, the code is recognised as a matrix-matrix multiplication, since
the second and third dimensions of D are accessed with non-zero strides.

This fixes the typo, which was made during the translation to C++ bindings
(https://reviews.llvm.org/D35845).

Reviewed By: Michael Kruse <llvm@meinersbur.de>

Differential Revision: https://reviews.llvm.org/D110491
2021-09-28 22:58:57 +05:00
Michael Kruse cad9f98a2a [Polly] Don't generate inter-iteration noalias metadata.
This metadata was intended to mark all accesses within an iteration to be pairwise non-aliasing, in this case because every memory of a base pointer is touched (read or write) at most once. This is typical for 'sweeps' over all data. The stated motivation from D30606 is to ensure that unrolled iterations are considered non-aliasing.

Rhe implemention had multiple issues:

 * The structure of the noalias metadata was malformed. D110026 added check in the verifier for this metadata, and the tests were failing since then.

 * This is not true for the outer loops of the BLIS matrix multiplication, where it was being inserted. Each element of A, B, C is accessed multiple times, as often as the loop not used as an index is iterating.

 * Scopes were added to SecondLevelOtherAliasScopeList (used for the !noalias scop list) on-the-fly when another SCEV was seen. This meant that previously visited instructions would not be updated with alias scopes that are only seen later, missing out those SCEVs they should not be aliasing with.

 * Since the !noalias scope list would ideally consists of all other SCEV for this base pointer, we might run quickly into scalability issues. Especially after unrolling there would probably at least once SCEV per instruction and unroll instance.

 * The inter-iteration noalias base pointer was not removed after leaving the loop marked with it, effectively marking everything after it to noalias as well.

A solution I considered was to mark each instruction as non-aliasing with its own scope. The instruction itself would obviously alias itself, but such construction might also be considered invalid. Duplicating the instruction (e.g. due to speculation) would mark the instruction non-aliasing with its clone. I don't want to go into this territory, especially since the original motivation of determining unrolled instances as noalias based on SCEV is the what scev-aa does as well.

This effectively reverts D30606 and D35761.
2021-09-20 22:20:17 -05:00
Riccardo Mori d3fdbda6b0 [Polly][Isl] Move to the new-polly-generator branch version of isl-noexceptions.h. NFCI
This is part of an effort to reduce the differences between the custom C++ bindings used right now by polly in `lib/External/isl/include/isl/isl-noxceptions.h` and the official isl C++ interface.

With this commit we are moving from the `polly-generator` branch to the `new-polly-generator` branch that is more mantainable and is based on the official C++ interface `cpp-checked.h`.

Changes made:
 - There are now many sublcasses for `isl::ast_node` representing different isl types. Use `isl::ast_node_for`, `isl::ast_node_user`, `isl::ast_node_block` and `isl::ast_node_mark` where needed.
 - There are now many sublcasses for `isl::schedule_node` representing different isl types. Use `isl::schedule_node_mark`, `isl::schedule_node_extension`, `isl::schedule_node_band` and `isl::schedule_node_filter` where needed.
 - Replace the `isl::*::dump` with `dumpIslObj` since the isl dump method is not exposed in the C++ interface.
 - `isl::schedule_node::get_child` has been renamed to `isl::schedule_node::child`
 - `isl::pw_multi_aff::get_pw_aff` has been renamed to `isl::pw_multi_aff::at`
 - The constructor `isl::union_map(isl::union_pw_multi_aff)` has been replaced with the static method `isl::union_map::from()`
 - Replace usages of `isl::val::add_ui` with `isl::val::add`
 - `isl::union_set_list::alloc` is now a constructor
 - All the `isl_size` values are now wrapped inside the class `isl::size` use `isl::size::release` to get the internal `isl_size` value where needed.
 - `isl-noexceptions.h` has been generated by 73f5ed1f4d

No functional change intended.

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D107225
2021-08-16 15:53:26 +02:00
Riccardo Mori 0813bd1696 [Polly][Isl] Use isl::*::ctx instead of isl::*::get_ctx. NFC
This is part of an effort to reduce the differences between the custom C++ bindings used right now by polly in `lib/External/isl/include/isl/isl-noxceptions.h` and the official isl C++ interface.

Changes made:
 - Use `isl::*::ctx()` instead of `isl::*::get_ctx()` (for example `isl::space::ctx()` instead of `isl::space::get_ctx()`)
 - Add `isl::` namespace in front of isl types to avoid confusion (for example `isl::space::ctx` and `isl::ctx`
 - `isl-noexceptions.h` has been generated by this b64e33c62d

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D105691
2021-07-09 21:14:14 +02:00
patacca f482497c38 [Polly][Isl] Use isl::set::tuple_dim, isl::map::domain_tuple_dim and isl::map::range_tuple_dim. NFC
This is part of an effort to reduce the differences between the custom C++ bindings used right now by polly in `lib/External/isl/include/isl/isl-noxceptions.h` and the official isl C++ interface.

Changes made:
 - Use `isl::set::tuple_dim` instead of `isl::set::dim` and `isl::set::n_dim`
 - Use `isl::map::domain_tuple_dim` instead of `isl::map::dim`
 - Use `isl::map::range_tuple_dim` instead of `isl::map::dim`
 - isl-noexceptions.h has been generated by this 45576e1b42

Note that not all the usage of `isl::{set,map}::dim` where replaced

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D104994
2021-07-06 11:20:45 +02:00
patacca 7c7978a122 [Polly][Isl] Removing explicit operator bool() from isl C++ bindings. NFC.
This is part of an effort to reduce the differences between the custom C++ bindings used right now by polly in `lib/External/isl/include/isl/isl-noxceptions.h` and the official isl C++ interface.

Changes made:
 - Removing explicit operator bool() from all the classes in the isl C++ bindings.
 - Replace each call to operator bool() to method `is_null()`.
 - isl-noexceptions.h has been generated by this 27396daac5

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D103976
2021-06-11 14:44:24 +02:00
Michael Kruse a56bd7dec8 [Polly][Matmul] Re-pack A in every iteration.
Packed_A must be copied repeatedly, not just for the first iteration of
the outer tile.

This fixes llvm.org/PR50557
2021-06-09 15:19:52 -05:00
Michael Kruse d123e983b3 [Polly] Move MatMul optimization into its own file. NFC.
Functions shared between generalized matrix-multiplication optimization
and other post-reschedule optimizations (tiling, prevect) are moved into
the schedule tree transformation utility ScheduleTreeTransform.
2021-06-04 23:22:30 -05:00