forked from OSchip/llvm-project
e01e4c9115
The current lowering from GPU to NVVM does not correctly handle the following cases when lowering the gpu shuffle op. 1. When the active width is set to 32 (all lanes), then the current approach computes (1 << 32) -1 which results in poison values in the LLVM IR. We fix this by defining the active mask as (-1) >> (32 - width). 2. In the case of shuffle up, the computation of the third operand c has to be different from the other 3 modes due to the op definition in the ISA reference. (https://docs.nvidia.com/cuda/parallel-thread-execution/index.html) Specifically, the predicate value is computed as j >= maxLane for up and j <= maxLane for all other modes. We fix this by computing maskAndClamp as 32 - width for this mode. TEST: We modify the existing test and add more checks for the up mode. Reviewed By: ThomasRaoux Differential Revision: https://reviews.llvm.org/D118086 |
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| .. | ||
| CMakeLists.txt | ||
| GPUToNVVM.td | ||
| LowerGpuOpsToNVVMOps.cpp | ||
| WmmaOpsToNvvm.cpp | ||