Fix ldbl-128ibm logl inaccuracy near 1 (bug 19351).
The ldbl-128ibm implementation of logl is inaccurate for arguments near 1, because when deciding whether to bypass a series expansion for log(1+z), where z = x-1, it compares the square of z rather than z itself with an epsilon value. This patch fixes that comparison, so eliminating the test failures for inaccuracy of logl in such cases. Tested for powerpc. [BZ #19351] * sysdeps/ieee754/ldbl-128ibm/e_logl.c (__ieee754_logl): When expanding log(1+z), compare z rather than its square with epsilon to determine when to avoid evaluating the expansion.
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2015-12-09 Joseph Myers <joseph@codesourcery.com>
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[BZ #19351]
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* sysdeps/ieee754/ldbl-128ibm/e_logl.c (__ieee754_logl): When
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expanding log(1+z), compare z rather than its square with epsilon
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to determine when to avoid evaluating the expansion.
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[BZ #19350]
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* sysdeps/ieee754/ldbl-128ibm/e_sinhl.c (__ieee754_sinhl):
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Increase overflow threshold.
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@ -270,7 +270,7 @@ __ieee754_logl(long double x)
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/* Series expansion of log(1+z). */
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w = z * z;
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/* Avoid spurious underflows. */
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if (__glibc_unlikely(w <= ldbl_epsilon))
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if (__glibc_unlikely (fabsl (z) <= ldbl_epsilon))
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y = 0.0L;
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else
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{
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