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authorJoseph Myers <joseph@codesourcery.com>2015-04-08 17:14:12 +0000
committerJoseph Myers <joseph@codesourcery.com>2015-04-08 17:14:12 +0000
commitae63c7ebedcaa57017df4cb8ff0494a4705321ee (patch)
tree4f2b413430bffe2a9c5354c5bd4e731106d7b832 /sysdeps
parentd5856d06c3ef62907f2865c502ada4baf3c9efa1 (diff)
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Fix dbl-64 atan in non-default rounding modes (bug 18197).
The dbl-64 implementation of atan does computations that expect to run in round-to-nearest mode, and in other modes the errors can accumulate to more than the maximum accepted 9ulp. This patch makes it use FE_TONEAREST internally, similar to other functions with such issues. Tested for x86_64 and x86; no ulps updates needed. [BZ #18197] * sysdeps/ieee754/dbl-64/s_atan.c: Include <fenv.h>. (atan): Set FE_TONEAREST mode for internal computations. * math/auto-libm-test-in: Add more tests of atan. * math/auto-libm-test-out: Regenerated.
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/ieee754/dbl-64/s_atan.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_atan.c b/sysdeps/ieee754/dbl-64/s_atan.c
index 7b598f1..5035ae8 100644
--- a/sysdeps/ieee754/dbl-64/s_atan.c
+++ b/sysdeps/ieee754/dbl-64/s_atan.c
@@ -41,6 +41,7 @@
#include "MathLib.h"
#include "uatan.tbl"
#include "atnat.h"
+#include <fenv.h>
#include <float.h>
#include <math.h>
#include <math_private.h>
@@ -81,6 +82,7 @@ atan (double x)
return x + x;
/* Regular values of x, including denormals +-0 and +-INF */
+ SET_RESTORE_ROUND (FE_TONEAREST);
u = (x < 0) ? -x : x;
if (u < C)
{