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| author | Joseph Myers <joseph@codesourcery.com> | 2016-12-15 23:52:18 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2016-12-15 23:52:18 +0000 |
| commit | 0a2546cdaa4284cc6ed6af06835fd858ba341838 (patch) | |
| tree | 7396415495f5f470f72cf4e73b77e01baebc1635 /ChangeLog | |
| parent | 67f779f1ead0bf38d1ca0e882e20c7ce0c03c204 (diff) | |
| download | glibc-0a2546cdaa4284cc6ed6af06835fd858ba341838.tar.gz glibc-0a2546cdaa4284cc6ed6af06835fd858ba341838.tar.xz glibc-0a2546cdaa4284cc6ed6af06835fd858ba341838.zip | |
Fix x86, x86_64 fmax, fmin sNaN handling, add tests (bug 20947).
Various fmax and fmin function implementations mishandle sNaN arguments: (a) When both arguments are NaNs, the return value should be a qNaN, but sometimes it is an sNaN if at least one argument is an sNaN. (b) Under TS 18661-1 semantics, if either argument is an sNaN then the result should be a qNaN (whereas if one argument is a qNaN and the other is not a NaN, the result should be the non-NaN argument). Various implementations treat sNaNs like qNaNs here. This patch fixes the x86 and x86_64 versions (ignoring float and double for 32-bit x86 given the inability to reliably avoid the sNaN turning into a qNaN before it gets to the called function). Tests of sNaN inputs to these functions are added. Note on architecture versions I haven't changed for this issue: AArch64 already gets this right (it uses a hardware instruction with the correct semantics for both quiet and signaling NaNs) and does not need changes. It's possible Alpha, IA64, SPARC might need changes (this would be shown by the testsuite if so). Tested for x86_64 and x86 (both i686 and i586 builds, to cover the different x86 implementations). [BZ #20947] * sysdeps/i386/fpu/s_fmaxl.S (__fmaxl): Add the arguments when either is a signaling NaN. * sysdeps/i386/fpu/s_fminl.S (__fminl): Likewise. Make code follow fmaxl more closely. * sysdeps/i386/i686/fpu/s_fmaxl.S (__fmaxl): Add the arguments when either is a signaling NaN. * sysdeps/i386/i686/fpu/s_fminl.S (__fminl): Likewise. * sysdeps/x86_64/fpu/s_fmax.S (__fmax): Likewise. * sysdeps/x86_64/fpu/s_fmaxf.S (__fmaxf): Likewise. * sysdeps/x86_64/fpu/s_fmaxl.S (__fmaxl): Likewise. * sysdeps/x86_64/fpu/s_fmin.S (__fmin): Likewise. * sysdeps/x86_64/fpu/s_fminf.S (__fminf): Likewise. * sysdeps/x86_64/fpu/s_fminl.S (__fminl): Likewise. * math/libm-test.inc (fmax_test_data): Add tests of sNaN inputs. (fmin_test_data): Likewise.
Diffstat (limited to 'ChangeLog')
| -rw-r--r-- | ChangeLog | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog index 523028da4a..3f7e5d6e20 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,22 @@ +2016-12-15 Joseph Myers <joseph@codesourcery.com> + + [BZ #20947] + * sysdeps/i386/fpu/s_fmaxl.S (__fmaxl): Add the arguments when + either is a signaling NaN. + * sysdeps/i386/fpu/s_fminl.S (__fminl): Likewise. Make code + follow fmaxl more closely. + * sysdeps/i386/i686/fpu/s_fmaxl.S (__fmaxl): Add the arguments + when either is a signaling NaN. + * sysdeps/i386/i686/fpu/s_fminl.S (__fminl): Likewise. + * sysdeps/x86_64/fpu/s_fmax.S (__fmax): Likewise. + * sysdeps/x86_64/fpu/s_fmaxf.S (__fmaxf): Likewise. + * sysdeps/x86_64/fpu/s_fmaxl.S (__fmaxl): Likewise. + * sysdeps/x86_64/fpu/s_fmin.S (__fmin): Likewise. + * sysdeps/x86_64/fpu/s_fminf.S (__fminf): Likewise. + * sysdeps/x86_64/fpu/s_fminl.S (__fminl): Likewise. + * math/libm-test.inc (fmax_test_data): Add tests of sNaN inputs. + (fmin_test_data): Likewise. + 2016-12-15 Andreas Schwab <schwab@suse.de> * support/support_test_main.c (support_test_main): Don't shadow |