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digitalmars.D.bugs - [Issue 5999] New: Inconsistent equality with array of NaNs between runtime and CTFE

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=5999

           Summary: Inconsistent equality with array of NaNs between
                    runtime and CTFE
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Mac OS X
            Status: NEW
          Keywords: wrong-code
          Severity: minor
          Priority: P2
         Component: druntime
        AssignedTo: nobody puremagic.com
        ReportedBy: kennytm gmail.com



In CTFE, an array of NaN will not be equal to itself. However, this return
'true' in the runtime:

-----------------------------------------------
bool f() {
    float[] h = [float.nan];
    float[] i = [float.nan];
    return h == i;
}
void main() {
    static assert(!f());    // ctfe is OK
    assert(!f());           // runtime asserts
}
-----------------------------------------------

The CTFE and runtime result should be consistent.

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May 14 2011
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=5999


Paul D. Anderson <paul.d.anderson comcast.net> changed:

           What    |Removed                     |Added
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                 CC|                            |paul.d.anderson comcast.net



14:01:19 PDT ---
At the risk of stating the obvious, the correct result for a NaN compared to
itself is false. I would assume (correct me if I'm wrong) that an array of NaN
compared to itself would therefore also be false, since each element is != to
itself. That is, the runtime assert is correct and the CTFE is incorrect.

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Jun 14 2011
prev sibling next sibling parent d-bugmail puremagic.com writes:
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Don <clugdbug yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |clugdbug yahoo.com.au





 At the risk of stating the obvious, the correct result for a NaN compared to
 itself is false. I would assume (correct me if I'm wrong) that an array of NaN
 compared to itself would therefore also be false, since each element is != to
 itself. 


Yes.


That is, the runtime assert is correct and the CTFE is incorrect.


I think you misread the code. CTFE returns not equal, runtime returns equal.

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Jun 14 2011
prev sibling parent d-bugmail puremagic.com writes:
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Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bugzilla digitalmars.com



22:05:03 PST ---
Yes, the runtime is in error here.

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Jan 20 2012