Resolves#99114.
Tasks completed:
- Implement `faceforward` in
`hlsl_intrinsics.h`/`hlsl_intrinsic_helpers.h`
- Implement `faceforward` SPIR-V target builtin in
`clang/include/clang/Basic/BuiltinsSPIRV.td`
- Add a SPIR-V fast path in `hlsl_intrinsic_helpers.h`
- Add sema checks for `faceforward` to `CheckSPIRVBuiltinFunctionCall`
in `clang/lib/Sema/SemaSPIRV.cpp`
- Add codegen for SPIR-V `faceforward` builtin to `EmitSPIRVBuiltinExpr`
in `SPIR.cpp`
- Add HLSL codegen tests to
`clang/test/CodeGenHLSL/builtins/faceforward.hlsl`
- Add SPIRV builtin codegen tests to
`clang/test/CodeGenSPIRV/Builtins/faceforward.c`
- Add sema tests to
`clang/test/SemaHLSL/BuiltIns/faceforward-errors.hlsl`
- Add spirv sema tests to
`clang/test/SemaSPIRV/BuiltIns/faceforward-errors.c`
- Create the `int_spv_faceforward` intrinsic in `IntrinsicsSPIRV.td`
- In `SPIRVInstructionSelector.cpp` create the `faceforward` lowering
and map it to `int_spv_faceforward` in
`SPIRVInstructionSelector::selectIntrinsic`
- Create SPIR-V backend test case in
`llvm/test/CodeGen/SPIRV/hlsl-intrinsics/faceforward.ll`
Incomplete tasks:
- Create SPIR-V backend test case in
`llvm/test/CodeGen/SPIRV/opencl/faceforward.ll`
- Not applicable because the OpenCL SPIR-V extended instruction set does
not include a `faceforward` function
Follow-up tasks:
- Implement pattern matching for `faceforward` in `SPIRVCombine.td` and
`SPIRVPreLegalizerCombiner.cpp`
- In `faceforward.ll`, change `--target-env spv1.4` to `vulkan1.3` and
update the test accordingly once
[#136344](https://github.com/llvm/llvm-project/issues/136344) has been
resolved
