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| author | Joseph Myers <joseph@codesourcery.com> | 2015-05-19 23:05:22 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2015-05-19 23:05:22 +0000 |
| commit | 526af54142db14c1edcd2d80dc1b56d33ff4e8ce (patch) | |
| tree | 04991e58f9d8c05a94a492eda37747bdcc8a4740 /sysdeps | |
| parent | 88ed594f5d431d855256edbe7e886c8cf4b575dc (diff) | |
| download | glibc-526af54142db14c1edcd2d80dc1b56d33ff4e8ce.tar.gz glibc-526af54142db14c1edcd2d80dc1b56d33ff4e8ce.tar.xz glibc-526af54142db14c1edcd2d80dc1b56d33ff4e8ce.zip | |
Fix i386 atanhl spurious underflows (bug 18049).
The i386 implementation of atanhl, for small arguments, does a calculation that involves computing twice the square of the argument, resulting in spurious underflows for some arguments. This patch fixes this by just returning the argument when its exponent is below -32, with underflow being forced as needed for subnormal arguments. Tested for x86 and x86_64. [BZ #18049] * sysdeps/i386/fpu/e_atanhl.S (__ieee754_atanhl): For exponents below -32, return the argument, with underflow if subnormal. * math/auto-libm-test-in: Add more tests of atanh. * math/auto-libm-test-out: Regenerated.
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/i386/fpu/e_atanhl.S | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/sysdeps/i386/fpu/e_atanhl.S b/sysdeps/i386/fpu/e_atanhl.S index 88a970378d..1ad6851058 100644 --- a/sysdeps/i386/fpu/e_atanhl.S +++ b/sysdeps/i386/fpu/e_atanhl.S @@ -56,6 +56,16 @@ ENTRY(__ieee754_atanhl) andl $0x7fff, %eax cmpl $0x7fff, %eax je 5f + cmpl $0x3fdf, %eax + jge 7f + // Exponent below -32; return x, with underflow if subnormal. + fldt 4(%esp) + cmpl $0, %eax + jne 8f + fld %st(0) + fmul %st(0) + fstp %st(0) +8: ret 7: #ifdef PIC |