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Fabian Schriever 18b4e0e518 Fix error in fdim/f for infinities
The comparison c == FP_INFINITE causes the function to return +inf as it
expects x = +inf to always be larger than y. This shortcut causes
several issues as it also returns +inf for the following cases:
 - fdim(+inf, +inf), expected (as per C99): +0.0
 - fdim(-inf, any non NaN), expected: +0.0

I don't see a reason to keep the comparison as all the infinity cases
return the correct result using just the ternary operation.
2020-03-10 15:11:23 +01:00

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C

/* Copyright (C) 2002 by Red Hat, Incorporated. All rights reserved.
*
* Permission to use, copy, modify, and distribute this software
* is freely granted, provided that this notice is preserved.
*/
#include "fdlibm.h"
#ifdef __STDC__
float fdimf(float x, float y)
#else
float fdimf(x,y)
float x;
float y;
#endif
{
if (__fpclassifyf(x) == FP_NAN) return(x);
if (__fpclassifyf(y) == FP_NAN) return(y);
return x > y ? x - y : 0.0;
}
#ifdef _DOUBLE_IS_32BITS
#ifdef __STDC__
double fdim(double x, double y)
#else
double fdim(x,y)
double x;
double y;
#endif
{
return (double) fdimf((float) x, (float) y);
}
#endif /* defined(_DOUBLE_IS_32BITS) */