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authorJoseph Myers <joseph@codesourcery.com>2015-02-25 11:13:41 +0000
committerJoseph Myers <joseph@codesourcery.com>2015-02-25 11:13:41 +0000
commit137cef7d433407bd2ded8bcc5bea70e5858df47a (patch)
treedeb0a6e04c5e7220d1e4eebcf59ab9d792a8eca6 /sysdeps/i386/fpu
parentcb43bb0d68f001fc3d6e054d712ab8794b5fd1de (diff)
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Fix ldbl-128ibm asinhl inaccuracy (bug 18020).
The ldbl-128ibm implementation of asinhl uses cut-offs of 0x1p28 and
0x1p-29 to determine when to use simpler formulas that avoid possible
overflow / underflow.  Both those cut-offs are inappropriate for this
format, resulting in large errors.  This patch changes the code to use
more appropriate cut-offs of 0x1p56 and 0x1p-56, adding tests around
the cut-offs for various floating-point formats.

Tested for powerpc.  Also tested for x86_64 and x86 and updated ulps.

	[BZ #18020]
	* sysdeps/ieee754/ldbl-128ibm/s_asinhl.c (__asinhl): Use 2**56 and
	2**-56 not 2**28 and 2**-29 as thresholds for simpler formulas.
	* math/auto-libm-test-in: Add more tests of asinh.
	* math/auto-libm-test-out: Regenerated.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
Diffstat (limited to 'sysdeps/i386/fpu')
-rw-r--r--sysdeps/i386/fpu/libm-test-ulps8
1 files changed, 4 insertions, 4 deletions
diff --git a/sysdeps/i386/fpu/libm-test-ulps b/sysdeps/i386/fpu/libm-test-ulps
index 0977557f02..3ba23a4fc5 100644
--- a/sysdeps/i386/fpu/libm-test-ulps
+++ b/sysdeps/i386/fpu/libm-test-ulps
@@ -68,14 +68,14 @@ ldouble: 1
 Function: "asinh_downward":
 double: 1
 float: 1
-ildouble: 1
+ildouble: 3
 ldouble: 3
 
 Function: "asinh_towardzero":
 double: 1
 float: 1
-ildouble: 1
-ldouble: 2
+ildouble: 3
+ldouble: 3
 
 Function: "asinh_upward":
 double: 1
@@ -83,7 +83,7 @@ float: 1
 idouble: 1
 ifloat: 1
 ildouble: 5
-ldouble: 2
+ldouble: 3
 
 Function: "atan2":
 ildouble: 1