aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
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
parent955774751b71c4bc94029dd541ad9d34634ec995 (diff)
downloadglibc-8f8f8ef7aba40ef883291e4c4d95a419c3327d70.tar
glibc-8f8f8ef7aba40ef883291e4c4d95a419c3327d70.tar.gz
glibc-8f8f8ef7aba40ef883291e4c4d95a419c3327d70.tar.bz2
glibc-8f8f8ef7aba40ef883291e4c4d95a419c3327d70.zip
[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.
-rw-r--r--ChangeLog6
-rw-r--r--sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c2
-rw-r--r--sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c2
3 files changed, 8 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog
index a8d731c75d..6161509499 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-04 Szabolcs Nagy <szabolcs.nagy@arm.com>
+
+ [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.
+
2017-10-03 H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/i386/start.S: Replace "leal main@GOT(%ebx), %eax" with
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;