Optimize ldexp and scalbn

diff --git a/ChangeLog b/ChangeLog
index 666a9ee785cbe662652f1499e600749e870c4e23..b137d4e2681da761cdd40b3d36dd26ef5fd634fe 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2012-01-10  Ulrich Drepper  <drepper@gmail.com>
+
+       * sysdeps/ieee754/dbl-64/s_scalbn.c: Add branch prediction.
+       * sysdeps/ieee754/dbl-64/wordsize-64/s_scalbn.c: Likewise.
+       * sysdeps/ieee754/flt-32/s_scalbnf.c: Likewise.
+       * sysdeps/ieee754/ldbl-96/s_scalbnl.c: Likewise.
+
+       * math/bits/math-finite.h: Add ldexp support.
+
 2012-01-10  Marek Polacek  <polacek@redhat.com>
 
        * locale/programs/localedef.h (show_archive_content): Add noreturn

diff --git a/math/bits/math-finite.h b/math/bits/math-finite.h
index dcf427ca81aa44a82d9a1126a7440426771d4cc2..00e07a13c9e8581421693365bf66ca0693e4aba3 100644 (file)
--- a/math/bits/math-finite.h
+++ b/math/bits/math-finite.h
@@ -1,5 +1,5 @@
 /* Entry points to finite-math-only compiler runs.
-   Copyright (C) 2011 Free Software Foundation, Inc.
+   Copyright (C) 2011, 2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -261,6 +261,13 @@ extern long double __REDIRECT_NTH (log2l, (long double), __log2l_finite);
 # endif
 #endif
 
+/* ldexp.  */
+extern double __REDIRECT_NTH (ldexp, (double, int), scalbn);
+extern float __REDIRECT_NTH (ldexpf, (float, int), scalbnf);
+#ifdef __MATH_DECLARE_LDOUBLE
+extern long double __REDIRECT_NTH (ldexpl, (long double, int), scalbnl);
+#endif
+
 /* pow.  */
 extern double __REDIRECT_NTH (pow, (double, double), __pow_finite);
 extern float __REDIRECT_NTH (powf, (float, float), __powf_finite);

diff --git a/sysdeps/ieee754/dbl-64/s_scalbn.c b/sysdeps/ieee754/dbl-64/s_scalbn.c
index 3dbfe8fef063765d909259b7ce10717355e12318..1e67dbe5ebd4a812d38551906aa420545a5e956c 100644 (file)
--- 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 25cf3b1699801eec1ad9357adf67225297fd0b0e..7f0e21f646fa177f902b965e48e19de1be9d3fd8 100644 (file)
--- 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 407cf607c7f801f56406da55d6ef0f7ca14e0023..3be2925a03a4263dbecef18c8c461ab71fbd1a6f 100644 (file)
--- 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 9f441fd1e926ded8a5cf9c8b8dedd26a3ad6e044..6a41920aca6197d3b1b82922e1edb4a9d07f80e5 100644 (file)
--- 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)