rampitec wrote: > Hi @rampitec > > With UBSan built binaries the MC/AMDGPU/literals.s testcase fails and > triggers UB like > > ``` > 07:33:04 ../lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:2246:59: runtime > error: left shift of negative value -54321 > 07:33:04 SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior > ../lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp:2246:59 > ``` > > It's this new shift that it complains on: > > ``` > Val = AMDGPU::isSISrcFPOperand(InstDesc, OpNum) ? Val << 32 : Lo_32(Val); > ```
I am happy to fix it, but I do not understand how a LEFT shift can be a UB? Low bits will be zero, right? High bits will be disposed. I really do not understand. https://github.com/llvm/llvm-project/pull/68740 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
