[Backport to 16] fpbuiltin-max-error support #2403
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Changes were cherry-picked from the following commit: c6fe12b Also cherry-picked fixes from: This changes add SPIR-V translator support for the SPIR-V extension documented here: KhronosGroup/SPIRV-Registry#193. This extension adds one decoration to represent maximum error for FP operations and adds the related Capability. SPIRV Headers support for representing this in SPIR-V: KhronosGroup/SPIRV-Headers#363 intel/llvm#8134 added a new call-site attribute associated with FP builtin intrinsics. This attribute is named 'fpbuiltin-max-error'. Following example shows how this extension is supported in the translator. The input LLVM IR uses new LLVM builtin calls to represent FP operations. An attribute named 'fpbuiltin-max-error' is used to represent the max-error allowed in the FP operation. Example Input LLVM: %t6 = call float @llvm.fpbuiltin.sin.f32(float %f1) KhronosGroup#2 attributes KhronosGroup#2 = { "fpbuiltin-max-error"="2.5" } This is translated into a SPIR-V instruction (for add/sub/mul/div/rem) and OpenCl extended instruction for other instructions. A decoration to represent the max-error is attached to the SPIR-V instruction. SPIR-V code: 4 Decorate 97 FPMaxErrorDecorationINTEL 1075838976 6 ExtInst 2 97 1 sin 88 No new support is added to support translating this SPIR_V back to LLVM. Existing support is used. The decoration is translated back into named metadata associated with the LLVM instruction. This can be readily consumed by backends. Based on input from @andykaylor, we emit attributes when the FP operation is translated back to a call to a builtin function and emit metadata otherwise. Translated LLVM code for basic math functions (add/sub/mul/div/rem): %t6 = fmul float %f1, %f2, !fpbuiltin-max-error !7 !7 = !{!"2.500000"} Translated LLVM code for other math functions: %t6 = call spir_func float @_Z3sinf(float %f1) KhronosGroup#3 attributes KhronosGroup#3 = { "fpbuiltin-max-error"="4.000000" }
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Changes were cherry-picked from the following commit: c6fe12b
This changes add SPIR-V translator support for the SPIR-V extension documented here: KhronosGroup/SPIRV-Registry#193. This extension adds one decoration to represent maximum error for FP operations and adds the related Capability. SPIRV Headers support for representing this in SPIR-V: KhronosGroup/SPIRV-Headers#363
intel/llvm#8134 added a new call-site attribute associated with FP builtin intrinsics. This attribute is named 'fpbuiltin-max-error'. Following example shows how this extension is supported in the translator. The input LLVM IR uses new LLVM builtin calls to represent FP operations. An attribute named 'fpbuiltin-max-error' is used to represent the max-error allowed in the FP operation. Example Input LLVM:
%t6 = call float @llvm.fpbuiltin.sin.f32(float %f1) #2 attributes #2 = { "fpbuiltin-max-error"="2.5" }
This is translated into a SPIR-V instruction (for add/sub/mul/div/rem) and OpenCl extended instruction for other instructions. A decoration to represent the max-error is attached to the SPIR-V instruction.
SPIR-V code:
4 Decorate 97 FPMaxErrorDecorationINTEL 1075838976 6 ExtInst 2 97 1 sin 88
No new support is added to support translating this SPIR_V back to LLVM. Existing support is used. The decoration is translated back into named metadata associated with the LLVM instruction. This can be readily consumed by backends.
Based on input from @andykaylor, we emit attributes when the FP operation is translated back to a call to a builtin function and emit metadata otherwise.
Translated LLVM code for basic math functions (add/sub/mul/div/rem): %t6 = fmul float %f1, %f2, !fpbuiltin-max-error !7 !7 = !{!"2.500000"}
Translated LLVM code for other math functions:
%t6 = call spir_func float @_Z3sinf(float %f1) #3
attributes #3 = { "fpbuiltin-max-error"="4.000000" }