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authorSzabolcs Nagy <szabolcs.nagy@arm.com>2017-10-03 17:13:18 +0100
committerSzabolcs Nagy <szabolcs.nagy@arm.com>2017-10-04 10:13:56 +0100
commit8f8f8ef7aba40ef883291e4c4d95a419c3327d70 (patch)
tree31b06c0b90a6b188783e2037e19c35e8530d3228 /sysdeps/ieee754/dbl-64
parent955774751b71c4bc94029dd541ad9d34634ec995 (diff)
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[BZ #22243] fix log2(0) and log(10) in downward rounding
On 64bit targets if the SVID compat wrapper is suppressed (e.g. static linking)
then log2(0) and log10(0) returned inf instead of -inf.

	[BZ #22243]
	* sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c (__ieee754_log10): Use fabs.
	* sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c (__ieee754_log2): Likewise.
Diffstat (limited to 'sysdeps/ieee754/dbl-64')
-rw-r--r--sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c2
-rw-r--r--sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c b/sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c
index 4f5a81669e..cd5567182f 100644
--- a/sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c
+++ b/sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c
@@ -65,7 +65,7 @@ __ieee754_log10 (double x)
   if (hx < INT64_C(0x0010000000000000))
     {				/* x < 2**-1022  */
       if (__glibc_unlikely ((hx & UINT64_C(0x7fffffffffffffff)) == 0))
-	return -two54 / (x - x);	/* log(+-0)=-inf */
+	return -two54 / fabs (x);	/* log(+-0)=-inf */
       if (__glibc_unlikely (hx < 0))
 	return (x - x) / (x - x);	/* log(-#) = NaN */
       k -= 54;
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c b/sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c
index 5ccb78cf03..f08d5b337d 100644
--- a/sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c
+++ b/sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c
@@ -81,7 +81,7 @@ __ieee754_log2 (double x)
   if (hx < INT64_C(0x0010000000000000))
     {				/* x < 2**-1022  */
       if (__glibc_unlikely ((hx & UINT64_C(0x7fffffffffffffff)) == 0))
-	return -two54 / (x - x);	/* log(+-0)=-inf */
+	return -two54 / fabs (x);	/* log(+-0)=-inf */
       if (__glibc_unlikely (hx < 0))
 	return (x - x) / (x - x);	/* log(-#) = NaN */
       k -= 54;