[llvm-commits] [llvm] r58964 - in /llvm/trunk: docs/LangRef.html lib/Bitcode/Reader/BitcodeReader.cpp lib/CodeGen/SelectionDAG/DAGCombiner.cpp lib/CodeGen/SelectionDAG/LegalizeDAG.cpp lib/CodeGen/SelectionDAG/LegalizeTypes.h lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp lib/CodeGen/SelectionDAG/SelectionDAG.cpp lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp lib/Transforms/Scalar/InstructionCombining.cpp lib/VMCore/ConstantFold.cpp lib/VMCore/Instructions.cpp lib/VMCore/Verifier.cpp

[Mon Ping Wang]

Hi Chris,

I took some .ll files that used shuffles and created bc files using  
llvm 2.4 llvm-as  and run them through a 2.4 opt and then called a TOT  
llc  on the llvm-as and opt generated bytecode files to generate  
assembly.  For the limited number of files that I tried, I didn't have  
any problems.  Is there some other experiment I should be doing?

Thanks,
   -- Mon Ping


On Nov 15, 2008, at 10:29 PM, Chris Lattner wrote:

> On Nov 9, 2008, at 8:46 PM, Mon P Wang wrote:
>> URL: http://llvm.org/viewvc/llvm-project?rev=58964&view=rev
>> Log:
>> Added support for the following definition of shufflevector
>> <result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <m x  
>> i32> <mask>
>
> Very nice Mon Ping!
>
> One import comment though:
>
>> +++ llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp Sun Nov  9  
>> 22:46:22 2008
>> @@ -1592,16 +1592,12 @@
>>          getValue(Record, OpNum, Vec1->getType(), Vec2))
>>        return Error("Invalid SHUFFLEVEC record");
>>
>> -      const Type *MaskTy =
>> -        VectorType::get(Type::Int32Ty,
>> -                        cast<VectorType>(Vec1->getType())- 
>> >getNumElements());
>> -
>> -      if (getValue(Record, OpNum, MaskTy, Mask))
>> +      if (getValueTypePair(Record, OpNum, NextValueNo, Mask))
>>        return Error("Invalid SHUFFLEVEC record");
>>      I = new ShuffleVectorInst(Vec1, Vec2, Mask);
>>      break;
>>    }
>
> AFAICT, this will break compatibility with LLVM 2.4 bc files.  This  
> isn't good.  It should be possible to check the number of operands  
> in Record.  If there are N+1 entries, it is the new format, if there  
> are N, it is the old format.  Please verify that you can read 2.4  
> (or earlier) bc files with shuffles in them.
>
> -Chris