[LLVMdev] Floating point comparison doubt

[Chris Lattner]

On Jun 22, 2009, at 3:56 AM, Sachin.Punyani at microchip.com wrote:

> Hi,
>
> In unordered floating point comparison before making a call for  
> comparison proper one node called UO_F32 is generated. In targets  
> this node is replaced with a call to __unordsf2.
>
> My doubts here
> 1)  What are these UO_F32 and O_F32 nodes for?
> 2)  What is this function (__unordsf2) supposed to do?
>

uo -> unordered,  o -> ordered.

unordered(x,y) is true if either x or y is a NaN
ordered(x,y) is true if neither x or y is a nan.

See also the CondCode enum in llvm/include/llvm/CodeGen/ 
SelectionDAGNodes.h.

-Chris
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