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Jeff Cohen wrote:
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Reid Spencer wrote:
<blockquote cite="mid1174605761.13912.605.camel@bashful.x10sys.com"
type="cite">
<pre wrap="">On Thu, 2007-03-22 at 15:50 -0700, leo han wrote:
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<pre wrap="">Hello, I have a question about the constant folding for fdiv instructions.
For the instruction "fdiv double 0.0, 0.0", the folded result is inf. I
think this should be nan. Can anyone tell me why it is not nan?
</pre>
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<pre wrap=""><!---->
I think the specification says that it is "undefined" so any value will
do. inf is just as undefined as nan.
Reid.</pre>
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<br>
In IEEE Std 754-1985, subclause 7.2- Division by Zero, it says:<br>
<br>
<i>"If the divisor is zero and the dividend is a finite nonzero
number,
then the division by zero shall be signaled. The result, when no trap
occurs, shall be a correctly signed (infinity symbol)(6.3)."<br>
<br>
</i>So LLVM is correct (assuming it handles signs correctly).<br>
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<br>
Never mind... only applies if a non-zero number is being divided by
zero.<br>
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