https://bugs.freedesktop.org/show_bug.cgi?id=78163
Priority: medium Bug ID: 78163 Assignee: dri-devel@lists.freedesktop.org Summary: Opencl app with multiprecision math return wrong results Severity: normal Classification: Unclassified OS: Linux (All) Reporter: alexxy@gentoo.org Hardware: x86-64 (AMD64) Status: NEW Version: git Component: Drivers/Gallium/r600 Product: Mesa
Opencl app that uses multiprecision math gives wrong results
App is https://github.com/eXtremal-ik7/xpmminer
$ ./xpmclminer -b --opencl-platform Mesa OpenCL platform available: Mesa 8 warnings generated. 8 warnings generated. [0] AMD TURKS; 1 compute units [1] AMD TURKS; 1 compute units * GPU 1 benchmark start: Multiply 256 bits CPU time: 4.868, GPU time: 4.131 (1.178 times faster) element index: 0 gmp: 79016B22 1C710C4A DF86F5C0 18E693EF D677434D 28B50A0A 4A2F8F5E 6FF1E1A6 C17B67E2 77B8CB65 8BA0DF48 3CD297F7 AD74948C 6B99D76B 8A81F331 DF8A45CB 8869E036 825665FF 9505CD30 543C80C6 96E3B1A5 72CE6A4A CEA9324B 7C37E23C gpu: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 results differ! Multiply 384 bits CPU time: 9.280, GPU time: 15.885 (0.584 times faster)