[llvm] r274193 - CodeGen: Add an explicit BuildMI overload for MachineInstr&

[Duncan P. N. Exon Smith via llvm-commits]

> On 2016-Jun-30, at 11:40, Justin Bogner <mail at justinbogner.com> wrote:
> 
> "Duncan P. N. Exon Smith via llvm-commits" <llvm-commits at lists.llvm.org>
> writes:
>> Author: dexonsmith
>> Date: Wed Jun 29 19:10:17 2016
>> New Revision: 274193
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=274193&view=rev
>> Log:
>> CodeGen: Add an explicit BuildMI overload for MachineInstr&
>> 
>> Add an explicit overload to BuildMI for MachineInstr& to deal with
>> insertions inside of instruction bundles.
> 
> You missed the other BuildMI MachineInstr* overload. I've added it in
> r274259 following the same pattern as here.

Yikes; sorry; thanks!

> 
>> - Use it to re-implement MachineInstr* to give it coverage.
>> 
>> - Document how the overload for MachineBasicBlock::instr_iterator
>>  differs from that for MachineBasicBlock::iterator (the previous
>>  (implicit) overload for MachineInstr&).
>> 
>> - Add a comment explaining why the MachineInstr& and MachineInstr*
>>  overloads don't universally forward to the
>>  MachineBasicBlock::instr_iterator overload.
>> 
>> Thanks to Justin for noticing the API quirk.  While this doesn't fix any
>> known bugs -- all uses of BuildMI with a MachineInstr& were previously
>> using MachineBasicBlock::iterator -- it protects against future bugs.
>> 
>> Modified:
>>    llvm/trunk/include/llvm/CodeGen/MachineInstrBuilder.h
>> 
>> Modified: llvm/trunk/include/llvm/CodeGen/MachineInstrBuilder.h
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineInstrBuilder.h?rev=274193&r1=274192&r2=274193&view=diff
>> ==============================================================================
>> --- llvm/trunk/include/llvm/CodeGen/MachineInstrBuilder.h (original)
>> +++ llvm/trunk/include/llvm/CodeGen/MachineInstrBuilder.h Wed Jun 29 19:10:17 2016
>> @@ -265,6 +265,12 @@ inline MachineInstrBuilder BuildMI(Machi
>>   return MachineInstrBuilder(MF, MI).addReg(DestReg, RegState::Define);
>> }
>> 
>> +/// This version of the builder inserts the newly-built instruction before
>> +/// the given position in the given MachineBasicBlock, and sets up the first
>> +/// operand as a destination virtual register.
>> +///
>> +/// If \c I is inside a bundle, then the newly inserted \a MachineInstr is
>> +/// added to the same bundle.
>> inline MachineInstrBuilder BuildMI(MachineBasicBlock &BB,
>>                                    MachineBasicBlock::instr_iterator I,
>>                                    const DebugLoc &DL, const MCInstrDesc &MCID,
>> @@ -275,16 +281,20 @@ inline MachineInstrBuilder BuildMI(Machi
>>   return MachineInstrBuilder(MF, MI).addReg(DestReg, RegState::Define);
>> }
>> 
>> -inline MachineInstrBuilder BuildMI(MachineBasicBlock &BB, MachineInstr *I,
>> +inline MachineInstrBuilder BuildMI(MachineBasicBlock &BB, MachineInstr &I,
>>                                    const DebugLoc &DL, const MCInstrDesc &MCID,
>>                                    unsigned DestReg) {
>> -  if (I->isInsideBundle()) {
>> -    MachineBasicBlock::instr_iterator MII(I);
>> -    return BuildMI(BB, MII, DL, MCID, DestReg);
>> -  }
>> +  // Calling the overload for instr_iterator is always correct.  However, the
>> +  // definition is not available in headers, so inline the check.
>> +  if (I.isInsideBundle())
>> +    return BuildMI(BB, MachineBasicBlock::instr_iterator(I), DL, MCID, DestReg);
>> +  return BuildMI(BB, MachineBasicBlock::iterator(I), DL, MCID, DestReg);
>> +}
>> 
>> -  MachineBasicBlock::iterator MII = I;
>> -  return BuildMI(BB, MII, DL, MCID, DestReg);
>> +inline MachineInstrBuilder BuildMI(MachineBasicBlock &BB, MachineInstr *I,
>> +                                   const DebugLoc &DL, const MCInstrDesc &MCID,
>> +                                   unsigned DestReg) {
>> +  return BuildMI(BB, *I, DL, MCID, DestReg);
>> }
>> 
>> /// This version of the builder inserts the newly-built instruction before the
>> 
>> 
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