[llvm-commits] [llvm] r105305 - /llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

[Duncan Sands]

>> LegalizeTypes has code for legalizing add-with-overflow, so I'm surprised it
>> doesn't work.
>
> It has code for promoting them, but not expanding them.

OK, I see - thanks for the explanation.  This doesn't seem hard to implement.
In fact you could even cheat, and turn the 64 bit add-with-overflow into a
65 bit add, with the top bit being used to compute the overflow flag.  That
should then all get expanded out automagically.

Ciao,

Duncan.