use scalbn or *2.0 instead of ldexp, fix fmal

Some code assumed ldexp(x, 1) is faster than 2.0*x,
but ldexp is a wrapper around scalbn which uses
multiplications inside, so this optimization is
wrong.

This commit also fixes fmal which accidentally
used ldexp instead of ldexpl loosing precision.

There are various additional changes from the
work-in-progress const cleanups.

1 files changed, 6 insertions, 6 deletions

diff --git a/src/math/fmal.c b/src/math/fmal.c
index cbaf46eb..be64f145 100644
--- a/src/math/fmal.c
+++ b/src/math/fmal.c
@@ -115,7 +115,7 @@ static inline long double add_and_denormalize(long double a, long double b, int
 		if (bits_lost != 1 ^ (int)(u.bits.manl & 1))
 			sum.hi = nextafterl(sum.hi, INFINITY * sum.lo);
 	}
-	return (ldexp(sum.hi, scale));
+	return scalbnl(sum.hi, scale);
 }
 
 /*
@@ -228,7 +228,7 @@ long double fmal(long double x, long double y, long double z)
 		}
 	}
 	if (spread <= LDBL_MANT_DIG * 2)
-		zs = ldexpl(zs, -spread);
+		zs = scalbnl(zs, -spread);
 	else
 		zs = copysignl(LDBL_MIN, zs);
 
@@ -254,7 +254,7 @@ long double fmal(long double x, long double y, long double z)
 		 */
 		fesetround(oround);
 		volatile long double vzs = zs; /* XXX gcc CSE bug workaround */
-		return (xy.hi + vzs + ldexpl(xy.lo, spread));
+		return xy.hi + vzs + scalbnl(xy.lo, spread);
 	}
 
 	if (oround != FE_TONEAREST) {
@@ -264,13 +264,13 @@ long double fmal(long double x, long double y, long double z)
 		 */
 		fesetround(oround);
 		adj = r.lo + xy.lo;
-		return (ldexpl(r.hi + adj, spread));
+		return scalbnl(r.hi + adj, spread);
 	}
 
 	adj = add_adjusted(r.lo, xy.lo);
 	if (spread + ilogbl(r.hi) > -16383)
-		return (ldexpl(r.hi + adj, spread));
+		return scalbnl(r.hi + adj, spread);
 	else
-		return (add_and_denormalize(r.hi, adj, spread));
+		return add_and_denormalize(r.hi, adj, spread);
 }
 #endif