[SYCL][Doc] Add initial draft of the device registry #18822
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jdnk
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@gmlueck Would you be able to check this? |
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Would it be possible to get a review on this? |
MrSidims
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Jul 15, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
vmaksimo
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Jul 29, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome. Original commit: KhronosGroup/SPIRV-LLVM-Translator@aaa23785dcbd7ca
jdnk
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
jdnk
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
jdnk
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
jdnk
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
jdnk
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
jdnk
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
jdnk
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
jdnk
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
jdnk
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
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Aug 13, 2025
This PR implements [SPV_INTEL_function_variants](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/spirv-extensions/SPV_INTEL_function_variants.asciidoc). It adds an optional SPIR-V to SPIR-V specialization pass that converts a multitarget module into a targeted one. The multitarget module does not have a LLVM IR representation, the extension only describes the specialization algorithm that takes place before converting the SPIR-V module into LLVM-IR. For this reason, it is only implemented as a part of SPIRVReader and not SPIRVWriter. The specialization is controlled by the user supplying the target device category, family, architecture, target ISA, supported features and/or supported capabilities via CLI flags. For example, to specialize for an Intel x86_64 CPU with Lion Cove microarchitecture that supports SSE, SSE2, SSE3, SSE4.1, SSE4.2, SSE4a, AVX, AVX2 and AVX512f features and Addresses, Linkage, Kernel, Int64 and Int8 capabilities, the user needs to provide the following flags: ``` llvm-spirv -r \ --spirv-ext=+SPV_INTEL_function_variants \ --fnvar-spec-enable \ --fnvar-spv-out targeted.spv \ --fnvar-category 1 --fnvar-family 1 --fnvar-arch 15 \ --fnvar-target 4 --fnvar-features '4,5,6,7,8,9,10,11,12' \ --fnvar-capabilities '4,5,6,11,39' \ multitarget.spv -o targeted.bc ``` Omitting a flag means that the target device supports all values for the flag. For example, in the above example, leaving out the `--fnvar-features` flag means that that the target device supports all features available for the x86_64 target. The integer values passed to the CLI flags are taken from a proposed [targets _registry_](intel/llvm#18822) accompanying the extension. (Capabilities correspond directly to the values defined in the SPIR-V specification). During the specialization pass, the specialization pass compares these CLI-supplied integers with the operands of `OpSpecConstantTargetINTEL`, `OpSpecConstantArchitectureINTEL` and `OpSpecConstantCapabilitiesINTEL` instructions in the input multitarget module, converts these instructions to constant true/false and proceeds with the specialization according to the rules described in the extension. Providing the CLI values as raw integer is not the most user friendly, and the translator does not validate the values in any way (eg., checking that feature X is allowed for target Y). This can be improved after the _registry_ is merged and more mature (version >0). Note: `--spirv-debug` can be used to print out details about what's happening when evaluating the above spec constants. It's useful for getting an insight into why a certain function variant got selected if the selection does not match the expected outcome.
bashbaug
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Aug 21, 2025
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Definitely not something that needs to be changed in this PR, but you may want to investigate something like the Mako template library to improve maintainability in the future.
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Yes, good idea. The current generation script is quite bare-bones, but it will need something more robust going forward. I added it to a new TODO section.
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Have you thought about including a license in this source file?
In a subsequent PR, it may be helpful to generate several different types of header files, such as a pure C header file like this one and a header file that uses C++ features.
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Actually I haven't thought about license, but there should be one. Perhaps not only in the header but for all files?
I saw SPIRV-Headers is licensed by CC-BY-4.0 and MIT. Would MIT with "The Khronos Group Inc." copyright be appropriate here?
pjaaskel
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Aug 21, 2025
jdnk
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This PR adds a registry containing enumerator values of device targets, features and architectures to be used with the SPV_INTEL_function_variants extension (and other extensions that find it useful). See the README file for details.
The purpose of the PR is to iterate on the registry format before filling in all the entries.
Targets and features come from inspecting compiler output (
llc --versionandllc --mtriple=<target> -mattr=help). A bulk of the architectures I took directly from sycl_ext_oneapi_device_architecture (mostly the GPUs). Others I added by hand (eg. Intel and ARM CPUs).Open questions: