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authorJoseph Myers <joseph@codesourcery.com>2015-05-15 17:47:29 +0000
committerJoseph Myers <joseph@codesourcery.com>2015-05-15 17:47:29 +0000
commit5a608ccc2d676aa124f6b55a7b20d071e408ca31 (patch)
tree41c40103e1b049d25bc519ca0688f48d82d61656 /math/auto-libm-test-in
parentff069f024ae8cf15d53429e034d67ddcece0f67a (diff)
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Fix tanf spurious underflows (bug 18221).
The flt-32 implementation of tanf produces spurious underflow
exceptions for some small arguments, through computing values on the
order of x^5.  This patch fixes this by adjusting the threshold for
returning x (or, as applicable, +/- 1/x) to 2**-13 (the next term in
the power series being x^3/3).

Tested for x86_64 and x86.

	[BZ #18221]
	* sysdeps/ieee754/flt-32/k_tanf.c (__kernel_tanf): Use 2**-13 not
	2**-28 as threshold for returning x or +/- 1/x.
	* math/auto-libm-test-in: Add more tests of tan.
	* math/auto-libm-test-out: Regenerated.
Diffstat (limited to 'math/auto-libm-test-in')
-rw-r--r--math/auto-libm-test-in2
1 files changed, 2 insertions, 0 deletions
diff --git a/math/auto-libm-test-in b/math/auto-libm-test-in
index 2a88403aa7..e483569dad 100644
--- a/math/auto-libm-test-in
+++ b/math/auto-libm-test-in
@@ -2418,6 +2418,8 @@ tan pi/4
 tan 0.75
 tan 0x1p65
 tan -0x1p65
+tan 0x1p-27
+tan -0x1p-27
 tan 0xc.9p-4
 tan 0xc.908p-4
 tan 0xc.90cp-4