diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | NEWS | 2 | ||||
| -rw-r--r-- | sysdeps/powerpc/fpu/e_sqrt.c | 33 |
3 files changed, 25 insertions, 16 deletions
@@ -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. + 2015-02-12 Roland McGrath <roland@hack.frob.com> * Makeconfig (ASFLAGS): Add -Werror=undef. @@ -9,7 +9,7 @@ Version 2.22 * The following bugs are resolved with this release: - 4719, 15467, 15790, 16560, 17912, 17932, 17944, 17949, 17965. + 4719, 15467, 15790, 16560, 17912, 17932, 17944, 17949, 17964, 17965. Version 2.21 diff --git a/sysdeps/powerpc/fpu/e_sqrt.c b/sysdeps/powerpc/fpu/e_sqrt.c index 0934faa5fe..9b55ef8390 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. */ |