remainder, remainderf, remainderl: Fix computation for large quotients.

* lib/remainder.c: Completely rewritten.
* lib/remainderf.c (remainderf): Use implementation of remainder.c with
USE_FLOAT.
* lib/remainderl.c (remainderl): Use implementation of remainder.c with
USE_LONG_DOUBLE.
* modules/remainder (Depends-on): Add isfinite, signbit, fabs, fmod,
isnand, isinf. Remove round, fma.
* modules/remainderf (Files): Add lib/remainder.c.
(Depends-on): Add isfinite, signbit, fabsf, fmodf, isnanf, isinf.
Remove roundf, fmaf.
* modules/remainderl (Files): Add lib/remainder.c.
(Depends-on): Add float, isfinite, signbit, fabsl, fmodl, isnanl,
isinf. Remove roundl, fmal.
* m4/remainder.m4 (gl_FUNC_REMAINDER): Update computation of
REMAINDER_LIBM.
* m4/remainderf.m4 (gl_FUNC_REMAINDERF): Update computation of
REMAINDERF_LIBM.
* m4/remainderl.m4 (gl_FUNC_REMAINDERL): Update computation of
REMAINDERL_LIBM.

1 files changed, 2 insertions, 25 deletions

diff --git a/lib/remainderl.c b/lib/remainderl.c
index 3476f948e2..474ebe217c 100644
--- a/lib/remainderl.c
+++ b/lib/remainderl.c
@@ -29,30 +29,7 @@ remainderl (long double x, long double y)
 
 #else
 
-long double
-remainderl (long double x, long double y)
-{
-  long double q = - roundl (x / y);
-  long double r = fmal (q, y, x); /* = x + q * y, computed in one step */
-  /* Correct possible rounding errors in the quotient x / y.  */
-  long double half_y = 0.5L * y;
-  if (y >= 0)
-    {
-      /* Expect -y/2 <= r <= y/2.  */
-      if (r > half_y)
-        q -= 1, r = fmal (q, y, x);
-      else if (r < - half_y)
-        q += 1, r = fmal (q, y, x);
-    }
-  else
-    {
-      /* Expect y/2 <= r <= -y/2.  */
-      if (r > - half_y)
-        q += 1, r = fmal (q, y, x);
-      else if (r < half_y)
-        q -= 1, r = fmal (q, y, x);
-    }
-  return r;
-}
+# define USE_LONG_DOUBLE
+# include "remainder.c"
 
 #endif