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| author | Joseph Myers <joseph@codesourcery.com> | 2015-02-26 12:57:21 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2015-02-26 12:57:21 +0000 |
| commit | 524ae9ea2e3ae9f5bf5d655595fda827e9dc50a1 (patch) | |
| tree | 363ab7a9bab473dc18c22b1179d8b549d8497f80 /math | |
| parent | 23d43090e0b275e47e09e859823e965a1eb323dc (diff) | |
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Fix ldbl-128ibm ilogbl near powers of 2 (bug 18029).
The ldbl-128ibm implementation of ilogbl produces incorrect results
when the high part of the argument is a power of 2 and the low part a
nonzero number with the opposite sign (and so the returned exponent
should be 1 less than that of the high part). For example, ilogbl
(0x1.ffffffffffffffp1L) returns 2 but should return 1. (This is
similar to (fixed) bug 16740 for frexpl, and bug 18030 for logbl.)
This patch adds checks for that case.
Tested for powerpc.
[BZ #18029]
* sysdeps/ieee754/ldbl-128ibm/e_ilogbl.c (__ieee754_ilogbl):
Adjust exponent of power of 2 down when low part has opposite
sign.
* math/libm-test.inc (ilogb_test_data): Add more tests.
Diffstat (limited to 'math')
| -rw-r--r-- | math/libm-test.inc | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/math/libm-test.inc b/math/libm-test.inc index b3396b6a79..6045764fd3 100644 --- a/math/libm-test.inc +++ b/math/libm-test.inc @@ -7219,6 +7219,11 @@ static const struct test_f_i_data ilogb_test_data[] = TEST_f_i (ilogb, 1024, 10, NO_INEXACT_EXCEPTION), TEST_f_i (ilogb, -2000, 10, NO_INEXACT_EXCEPTION), +#if defined TEST_LDOUBLE && LDBL_MANT_DIG >= 57 + TEST_f_i (ilogb, 0x1.ffffffffffffffp1L, 1, NO_INEXACT_EXCEPTION), + TEST_f_i (ilogb, -0x1.ffffffffffffffp1L, 1, NO_INEXACT_EXCEPTION), +#endif + /* ilogb (0.0) == FP_ILOGB0 plus invalid exception */ TEST_f_i (ilogb, 0.0, FP_ILOGB0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM), /* ilogb (qNaN) == FP_ILOGBNAN plus invalid exception */ |