[llvm] r182062 - Generate debug info for by-value struct args even if they are not used.

[Eric Christopher]

On Fri, May 17, 2013 at 12:35 PM, Bob Wilson <bob.wilson at apple.com> wrote:
>
> On May 16, 2013, at 4:44 PM, Adrian Prantl <aprantl at apple.com> wrote:
>
>> Author: adrian
>> Date: Thu May 16 18:44:12 2013
>> New Revision: 182062
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=182062&view=rev
>> Log:
>> Generate debug info for by-value struct args even if they are not used.
>> radar://problem/13865940
>>
>> Added:
>>    llvm/trunk/test/DebugInfo/X86/byvalstruct.ll
>> Modified:
>>    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
>>
>> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=182062&r1=182061&r2=182062&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
>> +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Thu May 16 18:44:12 2013
>> @@ -6753,9 +6753,15 @@ void SelectionDAGISel::LowerArguments(co
>>
>>     // If this argument is unused then remember its value. It is used to generate
>>     // debugging information.
>> -    if (I->use_empty() && NumValues)
>> +    if (I->use_empty() && NumValues) {
>>       SDB->setUnusedArgValue(I, InVals[i]);
>>
>> +      // Also remember any frame index for use in FastISel.
>> +      if (FrameIndexSDNode *FI =
>> +          dyn_cast<FrameIndexSDNode>(InVals[i].getNode()))
>> +        FuncInfo->setArgumentFrameIndex(I, FI->getIndex());
>> +    }
>
> dyn_cast may return 0 if the type does not match, yet you're unconditionally dereferencing the result.  If you're sure of the type, it should just be a regular cast.

Looks like it's under the conditional no?

-eric