Rename the oneAPI backend to Altera

[jmitrevs]

Description

This PR renames the old oneAPI branch as Altera (with the help of AI), and based on discussions in #1529, this removes oneAPI backwards compatibility.

Actual ahls compatibility is a added by cherry-picking the commits from #1529.

Type of change

• Documentation update
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Tests

The testing infrastructure does not currently support ahls so all the Altera backend tests are expected to fail. Not sure what is the best migration strategy for the tests. Maybe when we add back oneAPI support we go back to using that?

Test Configuration:

Checklist

• I have read the guidelines for contributing.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have installed and run pre-commit on the files I edited or added.
• I have added tests that prove my fix is effective or that my feature works.

[jmitrevs]

This is largely ready for review, except that we can't run ahls tests in our CI just yet.

[Copilot]

Pull request overview

Introduces the Altera HLS backend and migrates oneAPI-oriented implementation, reporting, documentation, and tests to Altera naming while retaining a legacy oneAPI wrapper.

Changes:

• Adds Altera SYCL templates, optimization passes, types, reporting, and registration.
• Migrates backend test matrices and synthesis baselines to Altera.
• Updates documentation for Altera HLS IP Gen and legacy oneAPI usage.

Reviewed changes

Copilot reviewed 79 out of 147 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
README.md	Updates supported-backend wording.
docs/api/configuration.rst	Uses Altera in configuration example.
docs/backend/altera.rst	Documents Altera and legacy oneAPI.
docs/backend/quartus.rst	Recommends migration to Altera.
docs/index.rst	Links Altera backend documentation.
docs/intro/setup.rst	Documents Altera toolchain setup.
docs/intro/status.rst	Updates backend support status.
docs/ir/ir.rst	Renames oneAPI references to Altera.
hls4ml/backends/__init__.py	Registers the Altera backend.
hls4ml/backends/altera/__init__.py	Initializes the Altera package.
hls4ml/backends/altera/altera_template.py	Renames backend template abstractions.
hls4ml/backends/altera/altera_types.py	Defines Altera-specific type converters.
hls4ml/backends/altera/passes/__init__.py	Initializes Altera passes.
hls4ml/backends/altera/passes/bn_quant.py	Migrates quantized batch-normalization imports.
hls4ml/backends/altera/passes/clone_templates.py	Migrates stream-cloning templates.
hls4ml/backends/altera/passes/convolution_templates.py	Migrates convolution templates.
hls4ml/backends/altera/passes/convolution_winograd.py	Adds Altera Winograd transformation.
hls4ml/backends/altera/passes/core_templates.py	Migrates core layer templates.
hls4ml/backends/altera/passes/einsum.py	Uses Altera product types.
hls4ml/backends/altera/passes/einsum_dense.py	Uses Altera dense product types.
hls4ml/backends/altera/passes/embedding_templates.py	Migrates embedding templates.
hls4ml/backends/altera/passes/feature_check.py	Updates unsupported-feature errors.
hls4ml/backends/altera/passes/merge_templates.py	Migrates merge templates.
hls4ml/backends/altera/passes/pointwise.py	Migrates pointwise-convolution passes.
hls4ml/backends/altera/passes/pooling_templates.py	Migrates pooling templates.
hls4ml/backends/altera/passes/quantization_templates.py	Migrates quantization templates.
hls4ml/backends/altera/passes/recurrent_templates.py	Migrates recurrent templates.
hls4ml/backends/altera/passes/reshaping_templates.py	Migrates reshape templates.
hls4ml/backends/altera/passes/resource_strategy.py	Renames resource-strategy reference.
hls4ml/backends/altera/passes/transform_types.py	Uses Altera type converters.
hls4ml/backends/fpga/fpga_types.py	Updates AC fixed-point commentary.
hls4ml/backends/fpga/passes/hgq_proxy_model.py	Adds Altera HGQ handling.
hls4ml/backends/vivado/passes/distributed_arithmetic.py	Supports Altera DA flavor selection.
hls4ml/report/__init__.py	Exports Altera report APIs.
hls4ml/report/altera_report.py	Renames report parsing and printing APIs.
hls4ml/templates/altera/CMakeLists.txt	Makes compiler selection configurable.
hls4ml/templates/altera/exception_handler.hpp	Adds SYCL exception handling.
hls4ml/templates/altera/firmware/defines.h	Uses the SYCL compatibility header.
hls4ml/templates/altera/firmware/myproject.cpp	Uses portable task-sequence namespace.
hls4ml/templates/altera/firmware/myproject.h	Uses portable Altera/Intel properties.
hls4ml/templates/altera/firmware/parameters.h	Adds generated parameter template.
hls4ml/templates/altera/firmware/nnet_utils/hls4ml_sycl.h	Selects Altera or Intel SYCL extensions.
hls4ml/templates/altera/firmware/nnet_utils/nnet_activation.h	Adds activation implementations.
hls4ml/templates/altera/firmware/nnet_utils/nnet_batchnorm.h	Adds parallel batch normalization.
hls4ml/templates/altera/firmware/nnet_utils/nnet_batchnorm_stream.h	Adds streaming batch normalization.
hls4ml/templates/altera/firmware/nnet_utils/nnet_code_gen.h	Adds code-generation placeholder.
hls4ml/templates/altera/firmware/nnet_utils/nnet_common.h	Centralizes SYCL compatibility includes.
hls4ml/templates/altera/firmware/nnet_utils/nnet_conv1d.h	Adds Conv1D dispatch.
hls4ml/templates/altera/firmware/nnet_utils/nnet_conv1d_resource.h	Adds resource Conv1D algorithms.
hls4ml/templates/altera/firmware/nnet_utils/nnet_conv1d_stream.h	Adds streaming Conv1D.
hls4ml/templates/altera/firmware/nnet_utils/nnet_conv2d.h	Adds Conv2D dispatch.
hls4ml/templates/altera/firmware/nnet_utils/nnet_depthconv1d.h	Adds depthwise Conv1D dispatch.
hls4ml/templates/altera/firmware/nnet_utils/nnet_depthconv1d_resource.h	Adds depthwise Conv1D implementation.
hls4ml/templates/altera/firmware/nnet_utils/nnet_depthconv2d.h	Adds depthwise Conv2D dispatch.
hls4ml/templates/altera/firmware/nnet_utils/nnet_depthconv2d_resource.h	Adds depthwise Conv2D implementation.
hls4ml/templates/altera/firmware/nnet_utils/nnet_dense.h	Adds dense resource implementation.
hls4ml/templates/altera/firmware/nnet_utils/nnet_dense_stream.h	Adds streaming dense implementation.
hls4ml/templates/altera/firmware/nnet_utils/nnet_einsum.h	Adds Einsum implementation.
hls4ml/templates/altera/firmware/nnet_utils/nnet_einsum_dense.h	Adds EinsumDense implementation.
hls4ml/templates/altera/firmware/nnet_utils/nnet_embed.h	Adds embedding implementation.
hls4ml/templates/altera/firmware/nnet_utils/nnet_embed_stream.h	Adds streaming embedding.
hls4ml/templates/altera/firmware/nnet_utils/nnet_helpers.h	Adds generated-project helpers.
hls4ml/templates/altera/firmware/nnet_utils/nnet_mult.h	Adds multiplication strategies.
hls4ml/templates/altera/firmware/nnet_utils/nnet_padding.h	Adds parallel zero padding.
hls4ml/templates/altera/firmware/nnet_utils/nnet_padding_stream.h	Adds streaming zero padding.
hls4ml/templates/altera/firmware/nnet_utils/nnet_printf.h	Adds device printf helper.
hls4ml/templates/altera/firmware/nnet_utils/nnet_recurrent_activation.h	Adds recurrent activation wrappers.
hls4ml/templates/altera/firmware/nnet_utils/nnet_recurrent_stream.h	Adds streaming GRU support.
hls4ml/templates/altera/firmware/nnet_utils/nnet_resize.h	Adds nearest-neighbor resize.
hls4ml/templates/altera/firmware/nnet_utils/nnet_resize_stream.h	Adds streaming resize.
hls4ml/templates/altera/firmware/nnet_utils/nnet_transpose.h	Adds transpose implementation.
hls4ml/templates/altera/firmware/nnet_utils/nnet_transpose_stream.h	Adds streaming transpose.
hls4ml/templates/altera/firmware/nnet_utils/nnet_types.h	Adds array, pipe, and shift-register types.
hls4ml/templates/altera/myproject_bridge.cpp	Uses portable FPGA selector namespace.
hls4ml/templates/altera/myproject_test.cpp	Uses portable FPGA selectors.
hls4ml/writer/__init__.py	Registers the Altera writer.
test/pytest/ci-template.yml	Relabels oneAPI environment setup.
test/pytest/conftest.py	Adds Altera synthesis configuration.
test/pytest/synthesis_helpers.py	Adds Altera report comparison.
test/pytest/test_activations.py	Migrates activation tests to Altera.
test/pytest/test_batchnorm.py	Migrates batch-normalization tests.
test/pytest/test_bit_exact_grouped_conv.py	Migrates grouped-convolution checks.
test/pytest/test_bit_exact_zeropadding.py	Migrates zero-padding bit-exact tests.
test/pytest/test_conv1d.py	Migrates Conv1D tests and IDs.
test/pytest/test_embed.py	Migrates embedding tests and IDs.
test/pytest/test_globalpooling.py	Migrates global-pooling tests.
test/pytest/test_keras_api.py	Migrates Keras API tests.
test/pytest/test_keras_v3_api.py	Migrates Keras v3 tests.
test/pytest/test_merge.py	Migrates merge tests.
test/pytest/test_multi_dense.py	Migrates multi-dense tests.
test/pytest/test_multiout_network.py	Migrates multi-output tests.
test/pytest/test_oneapi_backend.py	Tests Altera and legacy oneAPI generation.
test/pytest/test_pointwiseconv.py	Migrates pointwise-convolution tests.
test/pytest/test_pooling.py	Migrates pooling tests.
test/pytest/test_pytorch_api.py	Migrates PyTorch API tests.
test/pytest/test_qeinsum.py	Migrates quantized Einsum tests.
test/pytest/test_qkeras.py	Migrates QKeras tests.
test/pytest/test_qkerasV3.py	Migrates QKeras v3 tests.
test/pytest/test_qonnx.py	Migrates QONNX tests.
test/pytest/test_recurrent_pytorch.py	Migrates PyTorch recurrent tests.
test/pytest/test_repack_stream.py	Migrates stream-repacking tests.
test/pytest/test_report.py	Tests Altera report parsing.
test/pytest/test_report/Altera/loop_attr.ndjson	Adds sample loop report.
test/pytest/test_report/Altera/quartus.ndjson	Adds sample Quartus report.
test/pytest/test_report/Altera/summary.ndjson	Adds sample HLS report.
test/pytest/test_reshape.py	Migrates reshape tests.
test/pytest/test_rnn.py	Migrates recurrent test cases and IDs.
test/pytest/test_serialization.py	Migrates serialization tests.
test/pytest/test_stream_clone.py	Migrates stream-cloning tests.
test/pytest/test_transpose_concat.py	Migrates transpose/concatenate tests.
test/pytest/test_upsampling.py	Migrates upsampling tests.
test/pytest/test_zeropadding.py	Migrates zero-padding tests.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_pooling_Altera-channels_last-valid-MaxPooling2D.json	Adds synthesis baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_pooling_Altera-channels_last-valid-MaxPooling1D.json	Adds synthesis baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_pooling_Altera-channels_last-valid-AveragePooling2D.json	Adds synthesis baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_pooling_Altera-channels_last-valid-AveragePooling1D.json	Adds synthesis baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_pooling_Altera-channels_last-same-MaxPooling2D.json	Adds synthesis baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_pooling_Altera-channels_last-same-MaxPooling1D.json	Adds synthesis baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_pooling_Altera-channels_last-same-AveragePooling2D.json	Adds synthesis baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_pooling_Altera-channels_last-same-AveragePooling1D.json	Adds synthesis baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_dense_io_stream-Altera.json	Adds dense-stream baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_dense_io_parallel-Altera.json	Adds dense-parallel baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_conv2d_io_parallel-Altera-Resource-same-channels_last.json	Adds Conv2D baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_activations_io_stream-Altera-sigmoid.json	Adds activation baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_activations_io_stream-Altera-relu.json	Adds activation baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_activations_io_stream-Altera-prelu.json	Adds activation baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_activations_io_stream-Altera-leaky_relu.json	Adds activation baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_activations_io_stream-Altera-elu.json	Adds activation baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_activations_io_parallel-Altera-sigmoid.json	Adds activation baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_activations_io_parallel-Altera-relu.json	Adds activation baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_activations_io_parallel-Altera-prelu.json	Adds activation baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_activations_io_parallel-Altera-leaky_relu.json	Adds activation baseline.
test/pytest/baselines/Altera/2025.0.1/test_keras_api_test_activations_io_parallel-Altera-elu.json	Adds activation baseline.

Suppressed comments (2)

docs/backend/altera.rst:9

• This documentation explicitly promises that the oneAPI backend remains available, while the PR description says oneAPI backward compatibility is removed. Please make the implementation/documentation and stated breaking-change policy agree so users know whether backend='oneAPI' remains supported.
  hls4ml/backends/altera/passes/resource_strategy.py:13
• Correct the typo in the resource-strategy explanation.

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[jmitrevs]

Locally some Altera tests fail, so this is not ready for merging. I am curious if the analogous oneAPI tests pass. (I accidentally destroyed my oneAPI setup so I can't check locally at the moment.) They fail the same way in #1529.

[jmitrevs]

Superseded by #1536.