Optimize ldexp and scalbn

4 files changed, 48 insertions, 92 deletions

diff --git a/sysdeps/ieee754/dbl-64/s_scalbn.c b/sysdeps/ieee754/dbl-64/s_scalbn.c
index 3dbfe8fef0..1e67dbe5eb 100644
--- a/sysdeps/ieee754/dbl-64/s_scalbn.c
+++ b/sysdeps/ieee754/dbl-64/s_scalbn.c
@@ -1,4 +1,3 @@
-/* @(#)s_scalbn.c 5.1 93/09/24 */
 /*
  * ====================================================
  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
@@ -10,10 +9,6 @@
  * ====================================================
  */
 
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: s_scalbn.c,v 1.8 1995/05/10 20:48:08 jtc Exp $";
-#endif
-
 /*
  * scalbn (double x, int n)
  * scalbn(x,n) returns x* 2**n  computed by  exponent
@@ -24,44 +19,37 @@ static char rcsid[] = "$NetBSD: s_scalbn.c,v 1.8 1995/05/10 20:48:08 jtc Exp $";
 #include "math.h"
 #include "math_private.h"
 
-#ifdef __STDC__
 static const double
-#else
-static double
-#endif
 two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
 twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
 huge   = 1.0e+300,
 tiny   = 1.0e-300;
 
-#ifdef __STDC__
-	double __scalbn (double x, int n)
-#else
-	double __scalbn (x,n)
-	double x; int n;
-#endif
+double
+__scalbn (double x, int n)
 {
 	int32_t k,hx,lx;
 	EXTRACT_WORDS(hx,lx,x);
-        k = (hx&0x7ff00000)>>20;		/* extract exponent */
-        if (k==0) {				/* 0 or subnormal x */
-            if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
+	k = (hx&0x7ff00000)>>20;		/* extract exponent */
+	if (__builtin_expect(k==0, 0)) {	/* 0 or subnormal x */
+	    if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
 	    x *= two54;
 	    GET_HIGH_WORD(hx,x);
 	    k = ((hx&0x7ff00000)>>20) - 54;
 	    }
-        if (k==0x7ff) return x+x;		/* NaN or Inf */
-        k = k+n;
-        if (n> 50000 || k >  0x7fe)
+	if (__builtin_expect(k==0x7ff, 0)) return x+x;	/* NaN or Inf */
+	k = k+n;
+	if (__builtin_expect(n> 50000 || k >  0x7fe, 0))
 	  return huge*__copysign(huge,x); /* overflow  */
-	if (n< -50000) return tiny*__copysign(tiny,x); /*underflow*/
-        if (k > 0) 				/* normal result */
+	if (__builtin_expect(n< -50000, 0))
+	  return tiny*__copysign(tiny,x); /*underflow*/
+	if (__builtin_expect(k > 0, 1))		/* normal result */
 	    {SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20)); return x;}
-        if (k <= -54)
+	if (k <= -54)
 	  return tiny*__copysign(tiny,x); 	/*underflow*/
-        k += 54;				/* subnormal result */
+	k += 54;				/* subnormal result */
 	SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20));
-        return x*twom54;
+	return x*twom54;
 }
 weak_alias (__scalbn, scalbn)
 #ifdef NO_LONG_DOUBLE
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbn.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbn.c
index 25cf3b1699..7f0e21f646 100644
--- a/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbn.c
+++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbn.c
@@ -1,4 +1,3 @@
-/* @(#)s_scalbn.c 5.1 93/09/24 */
 /*
  * ====================================================
  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
@@ -20,39 +19,32 @@
 #include "math.h"
 #include "math_private.h"
 
-#ifdef __STDC__
 static const double
-#else
-static double
-#endif
 two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
 twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
 huge   = 1.0e+300,
 tiny   = 1.0e-300;
 
-#ifdef __STDC__
-	double __scalbn (double x, int n)
-#else
-	double __scalbn (x,n)
-	double x; int n;
-#endif
+double
+__scalbn (double x, int n)
 {
 	int64_t ix;
 	int64_t k;
 	EXTRACT_WORDS64(ix,x);
 	k = (ix >> 52) & 0x7ff;			/* extract exponent */
-	if (k==0) {				/* 0 or subnormal x */
+	if (__builtin_expect(k==0, 0)) {	/* 0 or subnormal x */
 	    if ((ix & UINT64_C(0xfffffffffffff))==0) return x; /* +-0 */
 	    x *= two54;
 	    EXTRACT_WORDS64(ix,x);
 	    k = ((ix >> 52) & 0x7ff) - 54;
 	    }
-	if (k==0x7ff) return x+x;		/* NaN or Inf */
+	if (__builtin_expect(k==0x7ff, 0)) return x+x;	/* NaN or Inf */
 	k = k+n;
-	if (n> 50000 || k >  0x7fe)
+	if (__builtin_expect(n> 50000 || k >  0x7fe, 0))
 	  return huge*__copysign(huge,x); /* overflow  */
-	if (n< -50000) return tiny*__copysign(tiny,x); /*underflow*/
-	if (k > 0)				/* normal result */
+	if (__builtin_expect(n< -50000, 0))
+	  return tiny*__copysign(tiny,x); /*underflow*/
+	if (__builtin_expect(k > 0, 1))		/* normal result */
 	    {INSERT_WORDS64(x,(ix&UINT64_C(0x800fffffffffffff))|(k<<52));
 	      return x;}
 	if (k <= -54)
diff --git a/sysdeps/ieee754/flt-32/s_scalbnf.c b/sysdeps/ieee754/flt-32/s_scalbnf.c
index 407cf607c7..3be2925a03 100644
--- a/sysdeps/ieee754/flt-32/s_scalbnf.c
+++ b/sysdeps/ieee754/flt-32/s_scalbnf.c
@@ -13,51 +13,39 @@
  * ====================================================
  */
 
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: s_scalbnf.c,v 1.4 1995/05/10 20:48:10 jtc Exp $";
-#endif
-
 #include "math.h"
 #include "math_private.h"
 
-#ifdef __STDC__
 static const float
-#else
-static float
-#endif
 two25   =  3.355443200e+07,	/* 0x4c000000 */
 twom25  =  2.9802322388e-08,	/* 0x33000000 */
 huge   = 1.0e+30,
 tiny   = 1.0e-30;
 
-#ifdef __STDC__
-	float __scalbnf (float x, int n)
-#else
-	float __scalbnf (x,n)
-	float x; int n;
-#endif
+float
+__scalbnf (float x, int n)
 {
 	int32_t k,ix;
 	GET_FLOAT_WORD(ix,x);
-        k = (ix&0x7f800000)>>23;		/* extract exponent */
-        if (k==0) {				/* 0 or subnormal x */
-            if ((ix&0x7fffffff)==0) return x; /* +-0 */
+	k = (ix&0x7f800000)>>23;		/* extract exponent */
+	if (__builtin_expect(k==0, 0)) {	/* 0 or subnormal x */
+	    if ((ix&0x7fffffff)==0) return x; /* +-0 */
 	    x *= two25;
 	    GET_FLOAT_WORD(ix,x);
 	    k = ((ix&0x7f800000)>>23) - 25;
 	    }
-        if (k==0xff) return x+x;		/* NaN or Inf */
-        k = k+n;
-        if (n> 50000 || k >  0xfe)
+	if (__builtin_expect(k==0xff, 0)) return x+x;	/* NaN or Inf */
+	k = k+n;
+	if (__builtin_expect(n> 50000 || k >  0xfe, 0))
 	  return huge*__copysignf(huge,x); /* overflow  */
-	if (n< -50000)
+	if (__builtin_expect(n< -50000, 0))
 	  return tiny*__copysignf(tiny,x);	/*underflow*/
-        if (k > 0) 				/* normal result */
+	if (__builtin_expect(k > 0, 1))		/* normal result */
 	    {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
-        if (k <= -25)
+	if (k <= -25)
 	    return tiny*__copysignf(tiny,x);	/*underflow*/
-        k += 25;				/* subnormal result */
+	k += 25;				/* subnormal result */
 	SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));
-        return x*twom25;
+	return x*twom25;
 }
 weak_alias (__scalbnf, scalbnf)
diff --git a/sysdeps/ieee754/ldbl-96/s_scalbnl.c b/sysdeps/ieee754/ldbl-96/s_scalbnl.c
index 9f441fd1e9..6a41920aca 100644
--- a/sysdeps/ieee754/ldbl-96/s_scalbnl.c
+++ b/sysdeps/ieee754/ldbl-96/s_scalbnl.c
@@ -14,10 +14,6 @@
  * ====================================================
  */
 
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: $";
-#endif
-
 /*
  * scalbnl (long double x, int n)
  * scalbnl(x,n) returns x* 2**n  computed by  exponent
@@ -28,44 +24,36 @@ static char rcsid[] = "$NetBSD: $";
 #include "math.h"
 #include "math_private.h"
 
-#ifdef __STDC__
 static const long double
-#else
-static long double
-#endif
 two64   =  1.8446744073709551616e19L,
 twom64  =  5.421010862427522170037e-20L,
 huge   = 1.0e+4900L,
 tiny   = 1.0e-4900L;
 
-#ifdef __STDC__
-	long double __scalbnl (long double x, int n)
-#else
-	long double __scalbnl (x,n)
-	long double x; int n;
-#endif
+long double
+__scalbnl (long double x, int n)
 {
 	int32_t k,es,hx,lx;
 	GET_LDOUBLE_WORDS(es,hx,lx,x);
-        k = es&0x7fff;				/* extract exponent */
-        if (k==0) {				/* 0 or subnormal x */
-            if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
+	k = es&0x7fff;				/* extract exponent */
+	if (__builtin_expect(k==0, 0)) {	/* 0 or subnormal x */
+	    if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
 	    x *= two64;
 	    GET_LDOUBLE_EXP(hx,x);
 	    k = (hx&0x7fff) - 64;
 	    }
-        if (k==0x7fff) return x+x;		/* NaN or Inf */
-        k = k+n;
-        if (n> 50000 || k > 0x7ffe)
+	if (__builtin_expect(k==0x7fff, 0)) return x+x;	/* NaN or Inf */
+	k = k+n;
+	if (__builtin_expect(n> 50000 || k > 0x7ffe, 0))
 	  return huge*__copysignl(huge,x); /* overflow  */
-	if (n< -50000)
+	if (__builtin_expect(n< -50000, 0))
 	  return tiny*__copysignl(tiny,x);
-        if (k > 0) 				/* normal result */
+	if (__builtin_expect(k > 0, 1))		/* normal result */
 	    {SET_LDOUBLE_EXP(x,(es&0x8000)|k); return x;}
-        if (k <= -64)
+	if (k <= -64)
 	    return tiny*__copysignl(tiny,x); 	/*underflow*/
-        k += 64;				/* subnormal result */
+	k += 64;				/* subnormal result */
 	SET_LDOUBLE_EXP(x,(es&0x8000)|k);
-        return x*twom64;
+	return x*twom64;
 }
 weak_alias (__scalbnl, scalbnl)