[CUDA] Implemented _[bi]mma* builtins.
These builtins provide access to the new integer and
sub-integer variants of MMA (matrix multiply-accumulate) instructions
provided by CUDA-10.x on sm_75 (AKA Turing) GPUs.
Also added a feature for PTX 6.4. While Clang/LLVM does not generate
any PTX instructions that need it, we still need to pass it through to
ptxas in order to be able to compile code that uses the new 'mma'
instruction as inline assembly (e.g used by NVIDIA's CUTLASS library
https://github.com/NVIDIA/cutlass/blob/master/cutlass/arch/mma.h#L101)
Differential Revision: https://reviews.llvm.org/D60279
llvm-svn: 359248
diff --git a/clang/lib/Driver/ToolChains/Cuda.cpp b/clang/lib/Driver/ToolChains/Cuda.cpp
index 7d01f4b..42eaf71 100644
--- a/clang/lib/Driver/ToolChains/Cuda.cpp
+++ b/clang/lib/Driver/ToolChains/Cuda.cpp
@@ -644,19 +644,25 @@
CC1Args.push_back("-mlink-builtin-bitcode");
CC1Args.push_back(DriverArgs.MakeArgString(LibDeviceFile));
- // Libdevice in CUDA-7.0 requires PTX version that's more recent than LLVM
- // defaults to. Use PTX4.2 by default, which is the PTX version that came with
- // CUDA-7.0.
- const char *PtxFeature = "+ptx42";
- // TODO(tra): CUDA-10+ needs PTX 6.3 to support new features. However that
- // requires fair amount of work on LLVM side. We'll keep using PTX 6.1 until
- // all prerequisites are in place.
- if (CudaInstallation.version() >= CudaVersion::CUDA_91) {
- // CUDA-9.1 uses new instructions that are only available in PTX6.1+
- PtxFeature = "+ptx61";
- } else if (CudaInstallation.version() >= CudaVersion::CUDA_90) {
- // CUDA-9.0 uses new instructions that are only available in PTX6.0+
- PtxFeature = "+ptx60";
+ // New CUDA versions often introduce new instructions that are only supported
+ // by new PTX version, so we need to raise PTX level to enable them in NVPTX
+ // back-end.
+ const char *PtxFeature = nullptr;
+ switch(CudaInstallation.version()) {
+ case CudaVersion::CUDA_101:
+ PtxFeature = "+ptx64";
+ break;
+ case CudaVersion::CUDA_100:
+ PtxFeature = "+ptx63";
+ break;
+ case CudaVersion::CUDA_91:
+ PtxFeature = "+ptx61";
+ break;
+ case CudaVersion::CUDA_90:
+ PtxFeature = "+ptx60";
+ break;
+ default:
+ PtxFeature = "+ptx42";
}
CC1Args.append({"-target-feature", PtxFeature});
if (DriverArgs.hasFlag(options::OPT_fcuda_short_ptr,