LOGICAL FUNCTION DLAISNAN(DIN1,DIN2)
*
* -- LAPACK auxiliary routine (version 3.1) --
* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
* November 2006
*
* .. Scalar Arguments ..
DOUBLE PRECISION DIN1,DIN2
* ..
*
* Purpose
* =======
*
* This routine is not for general use. It exists solely to avoid
* over-optimization in DISNAN.
*
* DLAISNAN checks for NaNs by comparing its two arguments for
* inequality. NaN is the only floating-point value where NaN != NaN
* returns .TRUE. To check for NaNs, pass the same variable as both
* arguments.
*
* Strictly speaking, Fortran does not allow aliasing of function
* arguments. So a compiler must assume that the two arguments are
* not the same variable, and the test will not be optimized away.
* Interprocedural or whole-program optimization may delete this
* test. The ISNAN functions will be replaced by the correct
* Fortran 03 intrinsic once the intrinsic is widely available.
*
* Arguments
* =========
*
* DIN1 (input) DOUBLE PRECISION
* DIN2 (input) DOUBLE PRECISION
* Two numbers to compare for inequality.
*
* =====================================================================
*
* .. Executable Statements ..
DLAISNAN = (DIN1.NE.DIN2)
RETURN
END