[llvm-commits] [llvm] r56087 - /llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp

[Dale Johannesen]

On Sep 11, 2008, at 1:27 AMPDT, Duncan Sands wrote:
>> Succumb utterly to compatibility and implement
>> __sync_fetch_and_nand as ANDC, even though that's
>> not what nand means.
>
> what's this about?

 From the function's name one would expect it to do a NAND operation,  
~(A&B), and that's what I thought when I implemented it on ppc (which  
conveniently has a NAND instruction).  In fact gcc generates ANDC,  
(~A)&B, consistently on all platforms AFAICT.  I don't see anything  
definitive in any documentation, so I'm going with gcc compatibility.   
(I don't imagine anybody is using this anyway.)