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Diffstat (limited to 'llvm/docs/SPIRVUsage.rst')
| -rw-r--r-- | llvm/docs/SPIRVUsage.rst | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/llvm/docs/SPIRVUsage.rst b/llvm/docs/SPIRVUsage.rst index fdefc53..b6cd4b4 100644 --- a/llvm/docs/SPIRVUsage.rst +++ b/llvm/docs/SPIRVUsage.rst @@ -232,7 +232,7 @@ Below is a list of supported SPIR-V extensions, sorted alphabetically by their e * - ``SPV_INTEL_int4`` - Adds support for 4-bit integer type, and allow this type to be used in cooperative matrices. * - ``SPV_KHR_float_controls2`` - - Adds ability to specify the floating-point environment in shaders. It can be used on whole modules and individual instructions. + - Adds execution modes and decorations to control floating-point computations in both kernels and shaders. It can be used on whole modules and individual instructions. SPIR-V representation in LLVM IR ================================ @@ -589,3 +589,31 @@ Group and Subgroup Operations For workgroup and subgroup operations, LLVM uses function calls to represent SPIR-V's group-based instructions. These builtins facilitate group synchronization, data sharing, and collective operations essential for efficient parallel computation. + +SPIR-V Instructions Mapped to LLVM Metadata +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Some SPIR-V instructions don't have a direct equivalent in the LLVM IR language. To +address this, the SPIR-V Target uses different specific LLVM named metadata to convey +the necessary information. The SPIR-V specification allows multiple module-scope +instructions, where as LLVM named metadata must be unique. Therefore, the encoding of +such instructions has the following format: + +.. code-block:: llvm + + !spirv.<OpCodeName> = !{!<InstructionMetadata1>, !<InstructionMetadata2>, ..} + !<InstructionMetadata1> = !{<Operand1>, <Operand2>, ..} + !<InstructionMetadata2> = !{<Operand1>, <Operand2>, ..} + +Below, you will find the mappings between SPIR-V instruction and their corresponding +LLVM IR representations. + ++--------------------+---------------------------------------------------------+ +| SPIR-V instruction | LLVM IR | ++====================+=========================================================+ +| OpExecutionMode | .. code-block:: llvm | +| | | +| | !spirv.ExecutionMode = !{!0} | +| | !0 = !{void @worker, i32 30, i32 262149} | +| | ; Set execution mode with id 30 (VecTypeHint) and | +| | ; literal `262149` operand. | ++--------------------+---------------------------------------------------------+ |