comiss vs. ucomiss

[Vladimir Kozlov]

Even if exceptions are masked CPU need some
logic to check it. I think, a program with
ucom will be faster if a data has a lot of QNaN.

Vladimir

Tom Rodriguez wrote:
> I was just making some comparisons between x86_32.ad and x86_64.ad and 
> noticed that x86_32.ad uses comiss/comisd for floating point compares 
> with SSE but x86_64.ad uses ucomiss/ucomisd.  The only difference 
> between them is that the ucom versions don't signal for quiet NaNs.  We 
> have fp exception suppressed so functionally it doesn't make any 
> difference.  It does seem like they should be doing the same thing 
> though.  Anyone know why they emit different things?
> 
> tom