Commit 037e4e65 authored by Dylan McKay's avatar Dylan McKay
Browse files

Merging r314891: 

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r314891 | dylanmckay | 2017-10-04 22:51:28 +1300 (Wed, 04 Oct 2017) | 8 lines

[AVR] Insert JMP for long branches

Previously, on long branches (relative jumps of >4 kB), an assertion
failure was hit, as AVRInstrInfo::insertIndirectBranch was not
implemented. Despite its name, it is called by the branch relaxator
for *all* unconditional jumps.

Patch by Thomas Backman.
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llvm-svn: 315833
parent a8575044

llvm/lib/Target/AVR/AVRInstrInfo.cpp

+16 −2
Original line number Diff line number Diff line
@@ -537,8 +537,7 @@ bool AVRInstrInfo::isBranchOffsetInRange(unsigned BranchOp, 
    llvm_unreachable("unexpected opcode!");

  case AVR::JMPk:

  case AVR::CALLk:

    assert(BrOffset >= 0 && "offset must be absolute address");

    return isUIntN(16, BrOffset);

    return true;

  case AVR::RCALLk:

  case AVR::RJMPk:

    return isIntN(13, BrOffset);
@@ -556,5 +555,20 @@ bool AVRInstrInfo::isBranchOffsetInRange(unsigned BranchOp, 
  }

}



unsigned AVRInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB,

                                            MachineBasicBlock &NewDestBB,

                                            const DebugLoc &DL,

                                            int64_t BrOffset,

                                            RegScavenger *RS) const {

    // This method inserts a *direct* branch (JMP), despite its name.

    // LLVM calls this method to fixup unconditional branches; it never calls

    // insertBranch or some hypothetical "insertDirectBranch".

    // See lib/CodeGen/RegisterRelaxation.cpp for details.

    // We end up here when a jump is too long for a RJMP instruction.

    auto &MI = *BuildMI(&MBB, DL, get(AVR::JMPk)).addMBB(&NewDestBB);



    return getInstSizeInBytes(MI);

}



} // end of namespace llvm

llvm/lib/Target/AVR/AVRInstrInfo.h

+6 −0
Original line number Diff line number Diff line
@@ -107,6 +107,12 @@ public: 


  bool isBranchOffsetInRange(unsigned BranchOpc,

                             int64_t BrOffset) const override;



  unsigned insertIndirectBranch(MachineBasicBlock &MBB,

                                MachineBasicBlock &NewDestBB,

                                const DebugLoc &DL,

                                int64_t BrOffset,

                                RegScavenger *RS) const override;

private:

  const AVRRegisterInfo RI;

};

llvm/test/CodeGen/AVR/branch-relaxation-long.ll

0 → 100644
+4137 −0

File added.

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