diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | NEWS | 4 | ||||
| -rw-r--r-- | sysdeps/powerpc/fpu/e_sqrt.c | 33 |
3 files changed, 26 insertions, 17 deletions
diff --git a/ChangeLog b/ChangeLog index 92b8a2e35c..a81d6234a7 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2015-02-12 Joseph Myers <joseph@codesourcery.com> + + [BZ #17964] + * sysdeps/powerpc/fpu/e_sqrt.c (__slow_ieee754_sqrt): Use + __builtin_fma instead of relying on contraction of a * b + c. + 2015-01-28 Adhemerval Zanellla <azanella@linux.vnet.ibm.com> [BZ #16576] diff --git a/NEWS b/NEWS index f62b876d81..bdbf52bd7c 100644 --- a/NEWS +++ b/NEWS @@ -12,8 +12,8 @@ Version 2.19.1 15946, 16009, 16545, 16574, 16576, 16623, 16657, 16695, 16743, 16758, 16759, 16760, 16878, 16882, 16885, 16916, 16932, 16943, 16958, 17048, 17062, 17069, 17079, 17137, 17153, 17213, 17263, 17269, 17325, 17523, - 17555, 17905, 18007, 18032, 18080, 18240, 18287, 18508, 18665, 18905, - 18928, 19018, 19779, 19791, 19879, 20010, 20112. + 17555, 17905, 17964, 18007, 18032, 18080, 18240, 18287, 18508, 18665, + 18905, 18928, 19018, 19779, 19791, 19879, 20010, 20112. * A buffer overflow in gethostbyname_r and related functions performing DNS requests has been fixed. If the NSS functions were called with a diff --git a/sysdeps/powerpc/fpu/e_sqrt.c b/sysdeps/powerpc/fpu/e_sqrt.c index 24dfe68625..022d71bcb0 100644 --- a/sysdeps/powerpc/fpu/e_sqrt.c +++ b/sysdeps/powerpc/fpu/e_sqrt.c @@ -99,38 +99,41 @@ __slow_ieee754_sqrt (double x) /* Here we have three Newton-Raphson iterations each of a division and a square root and the remainder of the argument reduction, all interleaved. */ - sd = -(sg * sg - sx); + sd = -__builtin_fma (sg, sg, -sx); fsgi = (xi0 + 0x40000000) >> 1 & 0x7ff00000; sy2 = sy + sy; - sg = sy * sd + sg; /* 16-bit approximation to sqrt(sx). */ + sg = __builtin_fma (sy, sd, sg); /* 16-bit approximation to + sqrt(sx). */ /* schedule the INSERT_WORDS (fsg, fsgi, 0) to get separation between the store and the load. */ INSERT_WORDS (fsg, fsgi, 0); iw_u.parts.msw = fsgi; iw_u.parts.lsw = (0); - e = -(sy * sg - almost_half); - sd = -(sg * sg - sx); + e = -__builtin_fma (sy, sg, -almost_half); + sd = -__builtin_fma (sg, sg, -sx); if ((xi0 & 0x7ff00000) == 0) goto denorm; - sy = sy + e * sy2; - sg = sg + sy * sd; /* 32-bit approximation to sqrt(sx). */ + sy = __builtin_fma (e, sy2, sy); + sg = __builtin_fma (sy, sd, sg); /* 32-bit approximation to + sqrt(sx). */ sy2 = sy + sy; /* complete the INSERT_WORDS (fsg, fsgi, 0) operation. */ fsg = iw_u.value; - e = -(sy * sg - almost_half); - sd = -(sg * sg - sx); - sy = sy + e * sy2; + e = -__builtin_fma (sy, sg, -almost_half); + sd = -__builtin_fma (sg, sg, -sx); + sy = __builtin_fma (e, sy2, sy); shx = sx * fsg; - sg = sg + sy * sd; /* 64-bit approximation to sqrt(sx), - but perhaps rounded incorrectly. */ + sg = __builtin_fma (sy, sd, sg); /* 64-bit approximation to + sqrt(sx), but perhaps + rounded incorrectly. */ sy2 = sy + sy; g = sg * fsg; - e = -(sy * sg - almost_half); - d = -(g * sg - shx); - sy = sy + e * sy2; + e = -__builtin_fma (sy, sg, -almost_half); + d = -__builtin_fma (g, sg, -shx); + sy = __builtin_fma (e, sy2, sy); fesetenv_register (fe); - return g + sy * d; + return __builtin_fma (sy, d, g); denorm: /* For denormalised numbers, we normalise, calculate the square root, and return an adjusted result. */ |