[LLVMdev] Ordered / Unordered FP compare are not handled properly on X86

Tim Northover t.p.northover at gmail.com
Thu Aug 29 00:19:37 PDT 2013


On 29 August 2013 06:31, Demikhovsky, Elena <elena.demikhovsky at intel.com> wrote:
> Should I open a ticket for this?

I think he was saying this is intended behaviour. Isn't the difference
between ucomiss and comiss just whether an exception is raised for
NaN?

If so, a compare that used that instruction would have to become more
like an "invoke" with a landingpad for the exception and so on,
wouldn't it? The current fcmp can already distinguish between ordered
and unordered, because ucomiss provides that information.

Tim.



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