[SPIRV] Add legalization for long vectors #165444
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This change sets the hasSideEffects flag to false on type and constant opcodes so that they can be considered trivially dead if their result is unused. This means that instruction selection will now be able to remove them.
The spv_bitcast intrinsic is currently replaced by an OpBitcast during prelegalization. This will cause a problem when we need to legalize the OpBitcast. The legalizer assumes that instruction already lowered to a target specific opcode is legal. We cannot lower it to a G_BITCAST because the bitcasts sometimes the LLT type will be the same, causing an error in the verifier, even if the SPIR-V types will be different. This commit keeps the intrinsic around until instructoin selection. We can create rules to legalize a G_INTRINISIC* instruction, and it does not create problem for the verifier.
The previous check for vector bitcasts in `loadVectorFromVector` only compared the number of elements, which is insufficient when the element types differ. This can lead to incorrect assumptions about the validity of the cast. This commit replaces the element count check with a comparison of the total size of the vectors in bits. This ensures that the bitcast is only performed between vectors of the same size, preventing potential miscompilations.
This commit refactors the SPIRV post-legalizer to use a worklist to process new instructions. Previously, the post-legalizer would iterate through all instructions and try to assign types. This could fail if a new instruction depended on another new instruction that had not been processed yet. The new implementation adds all new instructions that require a SPIR-V type to a worklist. It then iteratively processes the worklist until it is empty. This ensures that all dependencies are met before an instruction is processed. This change makes the post-legalizer more robust and fixes potential ordering issues with newly generated instructions. Existing tests cover existing functionality. More tests will be added as the legalizer is modified. Part of llvm#153091
…tcast-intrinsic' and 'legalize_ptr_cast' into legalize-long-vectors-final
This commit refactors the SPIRV post-legalizer to use a worklist to process new instructions. Previously, the post-legalizer would iterate through all instructions and try to assign types. This could fail if a new instruction depended on another new instruction that had not been processed yet. The new implementation adds all new instructions that require a SPIR-V type to a worklist. It then iteratively processes the worklist until it is empty. This ensures that all dependencies are met before an instruction is processed. This change makes the post-legalizer more robust and fixes potential ordering issues with newly generated instructions. Existing tests cover existing functionality. More tests will be added as the legalizer is modified. Part of llvm#153091
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This patch introduces the necessary infrastructure to legalize vector operations on vectors that are longer than what the SPIR-V target supports. For instance, shaders only support vectors up to 4 elements. The legalization is done by splitting the long vectors into smaller vectors of a legal size. Specifically, this patch does the following: - Introduces `vectorElementCountIsGreaterThan` and `vectorElementCountIsLessThanOrEqualTo` legality predicates. - Adds legalization rules for `G_SHUFFLE_VECTOR`, `G_EXTRACT_VECTOR_ELT`, `G_BUILD_VECTOR`, `G_CONCAT_VECTORS`, `G_SPLAT_VECTOR`, and `G_UNMERGE_VALUES`. - Handles `G_BITCAST` of long vectors by converting them to `@llvm.spv.bitcast` intrinsics which are then legalized. - Updates `selectUnmergeValues` to handle extraction of both scalars and vectors from a larger vector, using `OpCompositeExtract` and `OpVectorShuffle` respectively. - Adds a test case to verify the legalization of a bitcast between a `<8 x i32>` and `<4 x f64>`, which is a pattern generated by HLSL's `asuint` and `asdouble` intrinsics. Fixes: llvm#165444
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I need to rename the file.
This patch introduces the necessary infrastructure to legalize vector operations on vectors that are longer than what the SPIR-V target supports. For instance, shaders only support vectors up to 4 elements. The legalization is done by splitting the long vectors into smaller vectors of a legal size. Specifically, this patch does the following: - Introduces `vectorElementCountIsGreaterThan` and `vectorElementCountIsLessThanOrEqualTo` legality predicates. - Adds legalization rules for `G_SHUFFLE_VECTOR`, `G_EXTRACT_VECTOR_ELT`, `G_BUILD_VECTOR`, `G_CONCAT_VECTORS`, `G_SPLAT_VECTOR`, and `G_UNMERGE_VALUES`. - Handles `G_BITCAST` of long vectors by converting them to `@llvm.spv.bitcast` intrinsics which are then legalized. - Updates `selectUnmergeValues` to handle extraction of both scalars and vectors from a larger vector, using `OpCompositeExtract` and `OpVectorShuffle` respectively. - Adds a test case to verify the legalization of a bitcast between a `<8 x i32>` and `<4 x f64>`, which is a pattern generated by HLSL's `asuint` and `asdouble` intrinsics. Fixes: llvm#165444
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This patch introduces the necessary infrastructure to legalize vector
operations on vectors that are longer than what the SPIR-V target
supports. For instance, shaders only support vectors up to 4 elements.
The legalization is done by splitting the long vectors into smaller
vectors of a legal size.
Specifically, this patch does the following:
vectorElementCountIsGreaterThanandvectorElementCountIsLessThanOrEqualTolegality predicates.G_SHUFFLE_VECTOR,G_EXTRACT_VECTOR_ELT,G_BUILD_VECTOR,G_CONCAT_VECTORS,G_SPLAT_VECTOR, andG_UNMERGE_VALUES.G_BITCASTof long vectors by converting them to@llvm.spv.bitcastintrinsics which are then legalized.selectUnmergeValuesto handle extraction of both scalarsand vectors from a larger vector, using
OpCompositeExtractandOpVectorShufflerespectively.a
<8 x i32>and<4 x f64>, which is a pattern generated byHLSL's
asuintandasdoubleintrinsics.Fixes #165444