Optimize mpfr_prec_round.

Optimize mpfr_set (Case of both src & dest have the same precision).
Start optimizing mpfr_sub1.


git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@2535 280ebfd0-de03-0410-8827-d642c229c3f4

5 files changed, 22 insertions, 11 deletions

diff --git a/cmp2.c b/cmp2.c
index a64cd35ed..4b260feff 100644
--- a/cmp2.c
+++ b/cmp2.c
@@ -47,9 +47,10 @@ mpfr_cmp2 (mpfr_srcptr b, mpfr_srcptr c, mp_prec_t *cancel)
   MPFR_ASSERTD(MPFR_IS_FP(c));
 
   /* Optimized case x - x */
-  if (b == c)
+  if (MPFR_UNLIKELY(b == c))
     return 0;
 
+  /*FIXME: Useless for sub1 ? */
   if (MPFR_IS_ZERO(b))
     {
       if (MPFR_IS_ZERO(c))
diff --git a/mpfr-impl.h b/mpfr-impl.h
index 7fca300ea..8165e6aa1 100644
--- a/mpfr-impl.h
+++ b/mpfr-impl.h
@@ -292,6 +292,8 @@ long double __gmpfr_longdouble_volatile _MPFR_PROTO ((long double)) ATTRIBUTE_CO
 #define MPFR_ARE_SINGULAR(x,y) \
   (MPFR_UNLIKELY(MPFR_IS_SINGULAR(x)) || MPFR_UNLIKELY(MPFR_IS_SINGULAR(y)))
 
+/* TODO: Redo all the macros dealing with the signs */
+
 /* Without zeros */
 #define MPFR_ISNONNEG(x)  (MPFR_NOTZERO((x)) && MPFR_SIGN(x) > 0)
 #define MPFR_ISNEG(x)     (MPFR_NOTZERO((x)) && MPFR_SIGN(x) < 0)
@@ -312,8 +314,7 @@ long double __gmpfr_longdouble_volatile _MPFR_PROTO ((long double)) ATTRIBUTE_CO
   (MPFR_CHECK_SIGN(s), MPFR_SIGN(x) = s)
 #define MPFR_IS_POS_SIGN(s1) (s1 > 0)
 #define MPFR_IS_NEG_SIGN(s1) (s1 < 0)
-#define MPFR_MULT_SIGN(s1, s2) \
-  ((s1) * (s2))
+#define MPFR_MULT_SIGN(s1, s2) ((s1) * (s2))
 #define MPFR_SET_MULT_SIGN(x, s) \
   (MPFR_CHECK_SIGN(s), MPFR_SIGN(x) *= s)
 /* Transform a sign to 1 or -1 */
diff --git a/round_prec.c b/round_prec.c
index 42376ac26..d938ffb84 100644
--- a/round_prec.c
+++ b/round_prec.c
@@ -72,12 +72,12 @@ mpfr_round_raw_generic(mp_limb_t *yp, mp_limb_t *xp, mp_prec_t xprec,
       lomask = -1;
       himask = -1;
     }
-  MPFR_ASSERTN(nw >= 1);
+  MPFR_ASSERTD(nw >= 1);
 
   if (xprec <= yprec)
     { /* No rounding is necessary. */
       /* if yp=xp, maybe an overlap: MPN_COPY_DECR is ok when src <= dst */
-      MPFR_ASSERTN(nw >= xsize);
+      MPFR_ASSERTD(nw >= xsize);
       if (inexp)
         *inexp = 0;
       if (flag)
@@ -100,7 +100,7 @@ mpfr_round_raw_generic(mp_limb_t *yp, mp_limb_t *xp, mp_prec_t xprec,
           k = xsize - nw;
           if (!rw)
             k--;
-          MPFR_ASSERTN(k >= 0);
+          MPFR_ASSERTD(k >= 0);
           sb = xp[k] & lomask;  /* First non-significant bits */
           if (rnd_mode == GMP_RNDN)
             {
@@ -172,7 +172,7 @@ mpfr_prec_round (mpfr_ptr x, mp_prec_t prec, mp_rnd_t rnd_mode)
       MPFR_SET_ALLOC_SIZE(x, nw); /* new number of allocated limbs */
     }
 
-  if (MPFR_UNLIKELY(MPFR_IS_SINGULAR(x)))
+  if (MPFR_UNLIKELY( MPFR_IS_SINGULAR(x) ))
     {
       if (MPFR_IS_NAN(x))
 	MPFR_RET_NAN;
@@ -185,7 +185,7 @@ mpfr_prec_round (mpfr_ptr x, mp_prec_t prec, mp_rnd_t rnd_mode)
   TMP_MARK(marker); 
   tmp = TMP_ALLOC (nw * BYTES_PER_MP_LIMB);
   xp = MPFR_MANT(x);
-  carry = mpfr_round_raw (tmp, xp, MPFR_PREC(x), MPFR_SIGN(x) < 0,
+  carry = mpfr_round_raw (tmp, xp, MPFR_PREC(x), MPFR_IS_NEG(x),
                           prec, rnd_mode, &inexact);
   MPFR_PREC(x) = prec;
 
diff --git a/set.c b/set.c
index 83075e227..732235bbf 100644
--- a/set.c
+++ b/set.c
@@ -52,6 +52,16 @@ mpfr_set4 (mpfr_ptr a, mpfr_srcptr b, mp_rnd_t rnd_mode, int signb)
 	/* Should never reach this code */
 	MPFR_ASSERTN(1);
     }
+  else if (MPFR_LIKELY(MPFR_PREC(b) == MPFR_PREC(a)))
+    {
+      /* Same precision and b is not special: 
+       * just copy the mantissa, and set the exponent and the sign */
+      MPFR_CLEAR_FLAGS(a);
+      MPN_COPY(MPFR_MANT(a), MPFR_MANT(b), MPFR_LIMB_SIZE(b));
+      MPFR_SET_SIGN(a, signb);
+      MPFR_SET_EXP(a, MPFR_GET_EXP(b));
+      MPFR_RET(0);
+    }
   else
     {
       mp_limb_t *ap;
diff --git a/sub1.c b/sub1.c
index 6f4f900a4..d9814d4a1 100644
--- a/sub1.c
+++ b/sub1.c
@@ -49,11 +49,10 @@ mpfr_sub1 (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mp_rnd_t rnd_mode)
   an = 1 + (MPFR_PREC(a) - 1) / BITS_PER_MP_LIMB;
 
   sign = mpfr_cmp2 (b, c, &cancel);
-  if (sign == 0)
+  if (MPFR_UNLIKELY(sign == 0))
     {
       if (rnd_mode == GMP_RNDD)
         MPFR_SET_NEG(a);
-
       else
         MPFR_SET_POS(a);
       MPFR_SET_ZERO(a);
@@ -80,7 +79,7 @@ mpfr_sub1 (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mp_rnd_t rnd_mode)
     {
       mpfr_srcptr t;
       MPFR_CHANGE_SIGN(a);
-      t = b; b = c; c = t;
+      t = b; b = c; c = t;      
     }
 
   diff_exp = (mp_exp_unsigned_t) MPFR_GET_EXP (b) - MPFR_GET_EXP (c);