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authorJoseph Myers <joseph@codesourcery.com>2015-02-25 00:01:15 +0000
committerJoseph Myers <joseph@codesourcery.com>2015-02-25 00:01:15 +0000
commit440169d681cc9f422e8486f1324079bef0e0c35a (patch)
tree9b732f618ba081518cf0cca84ef33328526a4633 /sysdeps/x86_64
parentba7d2c543f7d69883ece7eab39bf6c5cd5dc3081 (diff)
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Fix ldbl-128ibm acoshl inaccuracy (bug 18019).
The ldbl-128ibm implementation of acoshl uses a cut-off of 0x1p28 to
determine when to use log(x) + log(2) as a formula.  That cut-off is
too small for this format, resulting in large errors.  This patch
changes it to a more appropriate cut-off of 0x1p56, 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 #18019]
	* sysdeps/ieee754/ldbl-128ibm/e_acoshl.c (__ieee754_acoshl): Use
	2**56 not 2**28 as threshold for log (2x) formula.
	* math/auto-libm-test-in: Add more tests of acosh.
	* 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/x86_64')
-rw-r--r--sysdeps/x86_64/fpu/libm-test-ulps17
1 files changed, 15 insertions, 2 deletions
diff --git a/sysdeps/x86_64/fpu/libm-test-ulps b/sysdeps/x86_64/fpu/libm-test-ulps
index 36e1b76811..cd9e44f4a4 100644
--- a/sysdeps/x86_64/fpu/libm-test-ulps
+++ b/sysdeps/x86_64/fpu/libm-test-ulps
@@ -29,20 +29,33 @@ ldouble: 1
 
 Function: "acosh":
 double: 1
+float: 1
 idouble: 1
+ifloat: 1
+ildouble: 1
+ldouble: 1
 
 Function: "acosh_downward":
+double: 1
 float: 1
-ildouble: 1
+idouble: 1
+ifloat: 1
+ildouble: 2
 ldouble: 2
 
 Function: "acosh_towardzero":
+double: 1
 float: 1
-ildouble: 1
+idouble: 1
+ifloat: 1
+ildouble: 2
 ldouble: 2
 
 Function: "acosh_upward":
 double: 1
+float: 1
+idouble: 1
+ifloat: 1
 ildouble: 1
 ldouble: 1