beanz added inline comments.
================ 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; ---------------- aaron.ballman wrote: > 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. Because HLSL’s library linking mode is pretty constrained, in practice this hasn’t hurt us yet. That said, I think we probably should consider some retroactive changes to how we handle float-16, especially in the presence of library shaders… I’ll try and float this topic in some team meetings this week and see if we can come up with a set of tweaks that may have limited impact on existing code. We might be able to change the default behavior in clang with a switch to toggle back to the old mode for legacy code. ================ Comment at: clang/lib/Driver/ToolChains/HLSL.cpp:177 + A->claim(); + continue; + } ---------------- `-fcgl` also should imply `-disable-llvm-options` 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
