[PATCH] Consolidate and inline calls to __acr

[Siddhesh Poyarekar <siddhesh at redhat dot com>]

Hi,

The __acr function is a simple comparison between the absolute values
of two mp numbers.  It is not used anywhere outside of the base
operations, so I have made it a static internal function.  The
performance improvement is not much (approx. 0.2%) with the current
code, but it gets better once the mantissa gets converted to int
(approx 0.5%).  However, I see this patch more as cleanup than as
being of any significant value in terms of performance.  I have
verified that the testsuite does not regress as a result of this
change.  OK to commit?


Siddhesh

ChangeLog:

	* sysdeps/ieee754/dbl-64/mpa.c (mcr): Remove.
	(__acr): Make static inline.
	(__add): Clean up and consolidate calls to __acr.
	(__sub): Likewise.
	* sysdeps/ieee754/dbl-64/mpa.h (__acr): Remove declaration.

diff --git a/sysdeps/ieee754/dbl-64/mpa.c b/sysdeps/ieee754/dbl-64/mpa.c
index e608cf1..26b2632 100644
--- a/sysdeps/ieee754/dbl-64/mpa.c
+++ b/sysdeps/ieee754/dbl-64/mpa.c
@@ -56,41 +56,33 @@ const mp_no mpone = {1, {1.0, 1.0}};
 const mp_no mptwo = {1, {1.0, 2.0}};
 #endif
 
-#ifndef NO___ACR
-/* mcr() compares the sizes of the mantissas of two multiple precision  */
-/* numbers. Mantissas are compared regardless of the signs of the       */
-/* numbers, even if x->d[0] or y->d[0] are zero. Exponents are also     */
-/* disregarded.                                                         */
-static int
-mcr(const mp_no *x, const mp_no *y, int p) {
-  int i;
-  for (i=1; i<=p; i++) {
-    if      (X[i] == Y[i])  continue;
-    else if (X[i] >  Y[i])  return  1;
-    else                    return -1; }
-  return 0;
-}
-
-
-/* acr() compares the absolute values of two multiple precision numbers */
-int
-__acr(const mp_no *x, const mp_no *y, int p) {
-  int i;
-
-  if      (X[0] == ZERO) {
-    if    (Y[0] == ZERO) i= 0;
-    else                 i=-1;
-  }
-  else if (Y[0] == ZERO) i= 1;
-  else {
-    if      (EX >  EY)   i= 1;
-    else if (EX <  EY)   i=-1;
-    else                 i= mcr(x,y,p);
-  }
+/* Compare the absolute values of two multiple precision numbers.  */
+static inline int
+__acr (const mp_no *x, const mp_no *y, int p)
+{
+  if (X[0] == ZERO || Y[0] == ZERO)
+    return (int) (X[0] - Y[0]);
 
-  return i;
+  if (EX >  EY)
+    return 1;
+  else if (EX <  EY)
+    return -1;
+  else
+    {
+      /* Mantissa may be different.  */
+      int i;
+      for (i=1; i<=p; i++)
+        {
+	  if (X[i] < Y[i])
+	    return -1;
+          else if (X[i] >  Y[i])
+	    return  1;
+	  else
+	    continue;
+	}
+    }
+  return 0;
 }
-#endif
 
 
 #if 0
@@ -394,22 +386,49 @@ sub_magnitudes(const mp_no *x, const mp_no *y, mp_no *z, int p) {
 
 void
 SECTION
-__add(const mp_no *x, const mp_no *y, mp_no *z, int p) {
-
-  int n;
+__add(const mp_no *x, const mp_no *y, mp_no *z, int p)
+{
+  if (X[0] == ZERO)
+    {
+      __cpy(y,z,p);
+      return;
+    }
+  else if (Y[0] == ZERO)
+    {
+      __cpy(x,z,p);
+      return;
+    }
 
-  if      (X[0] == ZERO)     {__cpy(y,z,p);  return; }
-  else if (Y[0] == ZERO)     {__cpy(x,z,p);  return; }
+  int n = __acr (x, y, p);
 
-  if (X[0] == Y[0])   {
-    if (__acr(x,y,p) > 0)      {add_magnitudes(x,y,z,p);  Z[0] = X[0]; }
-    else                     {add_magnitudes(y,x,z,p);  Z[0] = Y[0]; }
-  }
-  else                       {
-    if ((n=__acr(x,y,p)) == 1) {sub_magnitudes(x,y,z,p);  Z[0] = X[0]; }
-    else if (n == -1)        {sub_magnitudes(y,x,z,p);  Z[0] = Y[0]; }
-    else                      Z[0] = ZERO;
-  }
+  if (X[0] == Y[0])
+    {
+      if (n == 1)
+	{
+	  add_magnitudes(x,y,z,p);
+	  Z[0] = X[0];
+	}
+      else
+	{
+	  add_magnitudes(y,x,z,p);
+	  Z[0] = Y[0];
+	}
+    }
+  else
+    {
+      if (n == 1)
+	{
+	  sub_magnitudes(x,y,z,p);
+	  Z[0] = X[0];
+	}
+      else if (n == -1)
+	{
+	  sub_magnitudes(y,x,z,p);
+	  Z[0] = Y[0];
+	}
+      else
+	Z[0] = ZERO;
+    }
 }
 
 
@@ -419,22 +438,50 @@ __add(const mp_no *x, const mp_no *y, mp_no *z, int p) {
 
 void
 SECTION
-__sub(const mp_no *x, const mp_no *y, mp_no *z, int p) {
-
-  int n;
+__sub(const mp_no *x, const mp_no *y, mp_no *z, int p)
+{
+  if (X[0] == ZERO)
+    {
+      __cpy(y,z,p);
+      Z[0] = -Z[0];
+      return;
+    }
+  else if (Y[0] == ZERO)
+    {
+      __cpy(x,z,p);
+      return;
+    }
 
-  if      (X[0] == ZERO)     {__cpy(y,z,p);  Z[0] = -Z[0];  return; }
-  else if (Y[0] == ZERO)     {__cpy(x,z,p);                 return; }
+  int n = __acr (x, y, p);
 
-  if (X[0] != Y[0])    {
-    if (__acr(x,y,p) > 0)      {add_magnitudes(x,y,z,p);  Z[0] =  X[0]; }
-    else                     {add_magnitudes(y,x,z,p);  Z[0] = -Y[0]; }
-  }
-  else                       {
-    if ((n=__acr(x,y,p)) == 1) {sub_magnitudes(x,y,z,p);  Z[0] =  X[0]; }
-    else if (n == -1)        {sub_magnitudes(y,x,z,p);  Z[0] = -Y[0]; }
-    else                      Z[0] = ZERO;
-  }
+  if (X[0] != Y[0])
+    {
+      if (n == 1)
+	{
+	  add_magnitudes(x,y,z,p);
+	  Z[0] =  X[0];
+	}
+      else
+	{
+	  add_magnitudes(y,x,z,p);
+	  Z[0] = -Y[0];
+	}
+    }
+  else
+    {
+      if (n == 1)
+	{
+	  sub_magnitudes(x,y,z,p);
+	  Z[0] =  X[0];
+	}
+      else if (n == -1)
+	{
+	  sub_magnitudes(y,x,z,p);
+	  Z[0] = -Y[0];
+	}
+      else
+	Z[0] = ZERO;
+    }
 }
 
 
diff --git a/sysdeps/ieee754/dbl-64/mpa.h b/sysdeps/ieee754/dbl-64/mpa.h
index 2a2deb4..da6db31 100644
--- a/sysdeps/ieee754/dbl-64/mpa.h
+++ b/sysdeps/ieee754/dbl-64/mpa.h
@@ -66,7 +66,6 @@ extern const mp_no mptwo;
 
 #define ABS(x)   ((x) <  0  ? -(x) : (x))
 
-int __acr(const mp_no *, const mp_no *, int);
 // int  __cr(const mp_no *, const mp_no *, int);
 void __cpy(const mp_no *, mp_no *, int);
 // void __cpymn(const mp_no *, int, mp_no *, int);