aaron.ballman added a comment. In D124790#3489690 <https://reviews.llvm.org/D124790#3489690>, @python3kgae wrote:
> Add option -fcgl which output clang codeGen result to avoid test dependent on > build DirectX backend. Thanks -- I think this should actually be a separate patch though, because it's not really related to the `half` datatype. (You can always wait to land this patch until after the `-fcgl` one has landed.) Aside from the `-fcgl` flag, this looks ready to go though. ================ Comment at: clang/lib/Basic/LangOptions.cpp:197 - // OpenCL has half keyword - Opts.Half = Opts.OpenCL; + // OpenCL and HLSL have half keyword + Opts.Half = Opts.OpenCL || Opts.HLSL; ---------------- python3kgae wrote: > python3kgae wrote: > > aaron.ballman wrote: > > > python3kgae wrote: > > > > aaron.ballman wrote: > > > > > Shouldn't this be looking for HLSL 2018? Or shader model 6.2? > > > > half keyword is always available. > > > > Without enable_16bit_types, half will be like using half=float. > > > > With enable_16bit_types, half will be real half. > > > > > > > > The check for HLSL 2018 and shader model 6.2 will be in another PR, > > > > still WIP. I'll add FIXME about it. > > > > half keyword is always available. > > > > Without enable_16bit_types, half will be like using half=float. > > > > With enable_16bit_types, half will be real half. > > > > > > Is there room for change here, or is this strictly required by HLSL? This > > > strikes me as just begging to confuse users into creating ODR violations. > > > CC @beanz > > Here's the doc about half for dxc. > > https://github.com/microsoft/DirectXShaderCompiler/wiki/16-Bit-Scalar-Types > > > > Old doc for fxc (the old shader compiler for shader model <= 5.1) is here > > https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-scalar > > > > Change the behavior might affect a lot of existing shaders. > More detail about half from https://github.com/tex3d. > > half originally mapped to a fuzzy "partial precision" float, where some > operations were designated as _pp, meaning the implementation was free to use > lower-precision math for those operations (like 24-bit, but not specified for > the language). All storage in host-visible memory would still be float. > "partial precision" went away with DX9, eventually to be replaced with > min-precision with a specific minimum precision an implementation was allowed > to use. When "partial precision" went away, it simply mapped to float for > DX10+. > People could have tried to use it liberally when they thought 32-bit > precision wasn't necessary, without explicitly targeting/testing API/hardware > that actually supported lower precision. Thank you for the extra information, it sounds like we're stuck supporting this. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D124790/new/ https://reviews.llvm.org/D124790 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
