Asymmetric consumer element type in ObjectFifo

[yenjames]

Summary

This PR is a proposal to introduce an optional consumerElemType for asymmetric transfers in ObjectFifos.

• Producer sends elemType-sized transfers, consumer receives consumerElemType-sized transfers. Producer element count must be an integer multiple of consumer element count.

Example

Input — a single ObjectFifo with 40xi32 producer type and 10xi32 consumer type:

aie.objectfifo @wts(%mt, {%ct}, 1 : i32) : !aie.objectfifo<memref<40xi32>>  -> !aie.objectfifo<memref<10xi32>>
= [dense<0> : memref<40xi32>]                                                                                                                                            

After --aie-objectFifo-stateful-transform, the producer and consumer get independently-sized buffers and BD lengths:

// MemTile: 40xi32 buffer with static init, BD sends 40 elements
%wts_buff_0 = aie.buffer(%mem_tile) {sym_name = "wts_buff_0"} : memref<40xi32> = dense<0>
aie.dma_bd(%wts_buff_0 : memref<40xi32>, 0, 40) 

// CoreTile: 10xi32 buffer, BD receives 10 elements                                                                                                                                          
%wts_cons_buff_0 = aie.buffer(%core_tile) {sym_name = "wts_cons_buff_0"} : memref<10xi32>
aie.dma_bd(%wts_cons_buff_0 : memref<10xi32>, 0, 10)                                                                                                                                         

The MemTile DMA sends 40 elements, and the CoreTile DMA receives them 10 at a time across 4 acquire/release cycles.

Changes

• AIEOps.td: Optional consumerElemType attribute, -> assembly format, getConsumerElemTypeOrDefault() helper
• AIEDialect.cpp: Verifier (integer multiple check), parser/printer for -> <type> syntax, AcquireOp verifier accepts consumer type
• AIEObjectFifoStatefulTransform.cpp: requiresDMAs() returns true for asymmetric types, split fifo uses consumer type for consumer buffer
• python/dialects/aie.py: consumer_datatype parameter, acquire() returns consumer type for Consume port
• python/iron/dataflow/objectfifo.py: consumer_obj_type parameter plumbed through to low-level bindings
• Tests: verifier error test, two stateful transform tests (basic + initValues), IRON Python test

[github-actions]

Coverage Report

Created: 2026-05-27 17:45

Click here for information about interpreting this report.

Filename	Function Coverage	Line Coverage	Region Coverage	Branch Coverage
IR/AIEDialect.cpp	90.85%	86.56%	87.80%	79.87%
Transforms/AIEObjectFifoStatefulTransform.cpp	100.00%	94.86%	92.83%	86.21%
Totals	93.07%	90.45%	89.66%	82.42%

Generated by llvm-cov -- llvm version 18.1.3

[Copilot]

Pull request overview

This PR proposes adding an optional consumer element type to aie.objectfifo to support asymmetric transfer granularity, where the producer and consumer sides use different element sizes while remaining compatible (producer size is an integer multiple of consumer size). This spans IR syntax/parsing/verification, the stateful ObjectFifo transform, Python bindings, and new tests.

Changes:

• Extend aie.objectfifo with an optional consumerElemType and -> <type> assembly syntax, plus verifier support for producer/consumer size ratio.
• Update aie.objectfifo.acquire verification and the stateful transform to respect the consumer-side element type (buffer type + DMA BD lengths).
• Plumb the feature through Python (dialect + IRON) and add MLIR + Python regression tests.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
include/aie/Dialect/AIE/IR/AIEOps.td	Adds optional consumerElemType, custom -> assembly hook, and helper accessor.
lib/Dialect/AIE/IR/AIEDialect.cpp	Adds verifier for asymmetric sizing, parser/printer for ->, and relaxes acquire verifier to accept consumer type.
lib/Dialect/AIE/Transforms/AIEObjectFifoStatefulTransform.cpp	Forces DMA path for asymmetric FIFOs and uses consumer type for consumer-side split FIFO/buffer.
python/dialects/aie.py	Adds consumer_datatype plumbing and makes consumer-side acquire() return the consumer element type when provided.
python/iron/dataflow/objectfifo.py	Adds IRON-level consumer_obj_type and passes it to the dialect op builder.
test/dialect/AIE/objectfifo_bad.mlir	Adds a verifier-negative test for non-integer-multiple sizing and fixes formatting in an existing case.
test/objectFifo-stateful-transform/asymmetric_element_type/asymmetric_element_type.mlir	New stateful-transform test validating producer/consumer buffer and BD lengths with asymmetric types.
test/objectFifo-stateful-transform/asymmetric_element_type/asymmetric_with_initvalues.mlir	New stateful-transform test covering asymmetric types with initValues and depth>1.
test/python/objFifo_asymmetric.py	New Python test validating IRON plumbing and printed IR contains the -> consumer type.

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