[LLVMdev] VFCmp failing when unordered or UnsafeFPMath on x86
evan.cheng at apple.com
Fri Jun 13 18:03:54 CDT 2008
On Jun 13, 2008, at 12:27 AM, Nicolas Capens wrote:
> Hi all,
> When trying to generate a VFCmp instruction when UnsafeFPMath is set
> to true I get an assert “Unexpected CondCode” on my x86 system. This
> also happens with UnsafeFPMath set to false and using an unordered
> compare. Could someone look into this?
Have you filed a bug?
> While I’m at it, is there any reason why only the most significant
> bit of the return value of VFCmp is defined (according to the
> documentation)? Both AltiVec and SSE set the components of the
> result to either all 1’s or all 0’s. Having only the most
> significant bit doesn’t seem useful to me at all, and (arithmetic)
> shifting vectors to replicate the bit isn’t supported.
Nate can probably explain this better than anyone.
> Nicolas Capens
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu
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