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authorJoseph Myers <joseph@codesourcery.com>2015-09-30 21:44:42 +0000
committerJoseph Myers <joseph@codesourcery.com>2015-09-30 21:44:42 +0000
commit8c6c9236361fbc077769673c259828216403bc33 (patch)
tree04b02cf33c6654bc380d2c2ef986c41c4166d2ee /math
parent93e448cbed1095c88133f2a304b1bbba72e480af (diff)
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Fix i386 acosh (-qNaN) spurious "invalid" exception.
The i386 versions of acoshf and acosh raise a spurious "invalid"
exception for an argument that is a quiet NaN with the sign bit set.
The integer arithmetic to detect arguments < 1 also detects -NaN, and
then the computation 0 / 0 in that case raises the exception.  This
patch fixes this by using (x - x) / (x - x) as the computation in that
case instead, which will always raise the exception for non-NaN
arguments reaching that code, but not for quiet NaN arguments.

Tested for x86_64 and x86.

	[BZ #19032]
	* sysdeps/i386/fpu/e_acosh.S (__ieee754_acosh): For arguments < 1,
	compute result as (x - x) / (x - x) not as 0 / 0.
	* sysdeps/i386/fpu/e_acoshf.S (__ieee754_acoshf): Likewise.
	* math/libm-test.inc (acosh_test_data): Add another test of acosh.
Diffstat (limited to 'math')
-rw-r--r--math/libm-test.inc1
1 files changed, 1 insertions, 0 deletions
diff --git a/math/libm-test.inc b/math/libm-test.inc
index 744c66dbb1..8615957600 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -1790,6 +1790,7 @@ static const struct test_f_f_data acosh_test_data[] =
     TEST_f_f (acosh, plus_infty, plus_infty, ERRNO_UNCHANGED),
     TEST_f_f (acosh, minus_infty, qnan_value, INVALID_EXCEPTION|ERRNO_EDOM),
     TEST_f_f (acosh, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_f (acosh, -qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
 
     /* x < 1:  */
     TEST_f_f (acosh, 0.75L, qnan_value, INVALID_EXCEPTION|ERRNO_EDOM),