[llvm-commits] [llvm] r125458 - in /llvm/trunk: lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp test/CodeGen/X86/crash.ll

[Chris Lattner]

On Feb 13, 2011, at 3:28 AM, Duncan Sands wrote:

>> --- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp (original)
>> +++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp Sun Feb 13 03:10:56 2011
>> @@ -1167,13 +1167,19 @@
>>    unsigned NVTBits = NVT.getSizeInBits();
>>    EVT ShTy = N->getOperand(1).getValueType();
>> 
>> +  // If this is a large integer being legalized (e.g. an i512) then plop the
>> +  // shift amount down as a fixed i32.  The target shift amount may be something
>> +  // like i8, but this isn't enough to represent the shift amount.
>> +  if (NVTBits>  256)
>> +    ShTy = MVT::i32;
> 
> I'm confused as to why this helps.  ShTy was defined (see above) to be
> N->getOperand(1).getValueType()  How can that ever be too small?

You're right, there is a more general and quite pervasive problem here.  I'll revisit this.

-Chris