Yonghong Song f6a86e448a BPF: avoid NE/EQ loop exit condition ... Kuniyuki Iwashima reported in [1] that llvm compiler may convert a loop exit condition with "i < bound" to "i != bound", where "i" is the loop index variable and "bound" is the upper bound. In case that "bound" is not a constant, verifier will always have "i != bound" true, which will cause verifier failure since to verifier this is an infinite loop. The fix is to avoid transforming "i < bound" to "i != bound". In llvm, the transformation is done by IndVarSimplify pass. The compiler checks loop condition cost (i = i + 1) and if the cost is lower, it may transform "i < bound" to "i != bound". This patch implemented getArithmeticInstrCost() in BPF TargetTransformInfo class to return a higher cost for such an operation, which will prevent the transformation for the test case added in this patch. [1] https://lore.kernel.org/netdev/1994df05-8f01-371f-3c3b-d33d7836878c@fb.com/ Differential Revision: https://reviews.llvm.org/D107483 (cherry picked from commit e52946b9ababcbf8e6f40b1b15900ae2e795a1c6)		2021-08-06 12:45:53 -07:00
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AsmParser
Disassembler
MCTargetDesc
TargetInfo
BPF.h
BPF.td
BPFAbstractMemberAccess.cpp
BPFAdjustOpt.cpp
BPFAsmPrinter.cpp
BPFCallingConv.td
BPFCheckAndAdjustIR.cpp
BPFCORE.h
BPFFrameLowering.cpp
BPFFrameLowering.h
BPFInstrFormats.td
BPFInstrInfo.cpp
BPFInstrInfo.h
BPFInstrInfo.td
BPFISelDAGToDAG.cpp
BPFISelLowering.cpp
BPFISelLowering.h
BPFMCInstLower.cpp
BPFMCInstLower.h
BPFMIChecking.cpp
BPFMIPeephole.cpp
BPFMISimplifyPatchable.cpp
BPFPreserveDIType.cpp
BPFRegisterInfo.cpp
BPFRegisterInfo.h
BPFRegisterInfo.td
BPFSelectionDAGInfo.cpp
BPFSelectionDAGInfo.h
BPFSubtarget.cpp
BPFSubtarget.h
BPFTargetMachine.cpp
BPFTargetMachine.h
BPFTargetTransformInfo.h
BTF.def
BTF.h
BTFDebug.cpp
BTFDebug.h
CMakeLists.txt