Modified Files:

	ChangeLog generated/matmul_c4.c generated/matmul_c8.c
	generated/matmul_i4.c generated/matmul_i8.c
	generated/matmul_r4.c generated/matmul_r8.c m4/matmul.m4

2004-11-18  Victor Leikehman  <lei@il.ibm.com>

	* m4/matmul.m4: Loops reordered to improve cache behavior.
	* generated/matmul_??.c: Regenerated.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@90853 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 94 insertions, 60 deletions

diff --git a/libgfortran/generated/matmul_c8.c b/libgfortran/generated/matmul_c8.c
index 7ed46ec57a9..bc51e4a9db3 100644
--- a/libgfortran/generated/matmul_c8.c
+++ b/libgfortran/generated/matmul_c8.c
@@ -21,37 +21,46 @@ Boston, MA 02111-1307, USA.  */
 
 #include "config.h"
 #include <stdlib.h>
+#include <string.h>
 #include <assert.h>
 #include "libgfortran.h"
 
-/* Dimensions: retarray(x,y) a(x, count) b(count,y).
-   Either a or b can be rank 1.  In this case x or y is 1.  */
+/* This is a C version of the following fortran pseudo-code. The key
+   point is the loop order -- we access all arrays column-first, which
+   improves the performance enough to boost galgel spec score by 50%.
+
+   DIMENSION A(M,COUNT), B(COUNT,N), C(M,N)
+   C = 0
+   DO J=1,N
+     DO K=1,COUNT
+       DO I=1,M
+         C(I,J) = C(I,J)+A(I,K)*B(K,J)
+*/
+
 void
 __matmul_c8 (gfc_array_c8 * retarray, gfc_array_c8 * a, gfc_array_c8 * b)
 {
   GFC_COMPLEX_8 *abase;
   GFC_COMPLEX_8 *bbase;
   GFC_COMPLEX_8 *dest;
-  GFC_COMPLEX_8 res;
-  index_type rxstride;
-  index_type rystride;
-  index_type xcount;
-  index_type ycount;
-  index_type xstride;
-  index_type ystride;
-  index_type x;
-  index_type y;
-
-  GFC_COMPLEX_8 *pa;
-  GFC_COMPLEX_8 *pb;
-  index_type astride;
-  index_type bstride;
-  index_type count;
-  index_type n;
+
+  index_type rxstride, rystride, axstride, aystride, bxstride, bystride;
+  index_type x, y, n, count, xcount, ycount;
 
   assert (GFC_DESCRIPTOR_RANK (a) == 2
           || GFC_DESCRIPTOR_RANK (b) == 2);
 
+/* C[xcount,ycount] = A[xcount, count] * B[count,ycount]
+
+   Either A or B (but not both) can be rank 1:
+
+   o One-dimensional argument A is implicitly treated as a row matrix
+     dimensioned [1,count], so xcount=1.
+
+   o One-dimensional argument B is implicitly treated as a column matrix
+     dimensioned [count, 1], so ycount=1.
+  */
+
   if (retarray->data == NULL)
     {
       if (GFC_DESCRIPTOR_RANK (a) == 1)
@@ -95,8 +104,10 @@ __matmul_c8 (gfc_array_c8 * retarray, gfc_array_c8 * a, gfc_array_c8 * b)
 
   if (GFC_DESCRIPTOR_RANK (retarray) == 1)
     {
-      rxstride = retarray->dim[0].stride;
-      rystride = rxstride;
+      /* One-dimensional result may be addressed in the code below
+	 either as a row or a column matrix. We want both cases to
+	 work. */
+      rxstride = rystride = retarray->dim[0].stride;
     }
   else
     {
@@ -104,65 +115,88 @@ __matmul_c8 (gfc_array_c8 * retarray, gfc_array_c8 * a, gfc_array_c8 * b)
       rystride = retarray->dim[1].stride;
     }
 
-  /* If we have rank 1 parameters, zero the absent stride, and set the size to
-     one.  */
+
   if (GFC_DESCRIPTOR_RANK (a) == 1)
     {
-      astride = a->dim[0].stride;
-      count = a->dim[0].ubound + 1 - a->dim[0].lbound;
-      xstride = 0;
-      rxstride = 0;
+      /* Treat it as a a row matrix A[1,count]. */
+      axstride = a->dim[0].stride;
+      aystride = 1;
+
       xcount = 1;
+      count = a->dim[0].ubound + 1 - a->dim[0].lbound;
     }
   else
     {
-      astride = a->dim[1].stride;
+      axstride = a->dim[0].stride;
+      aystride = a->dim[1].stride;
+
       count = a->dim[1].ubound + 1 - a->dim[1].lbound;
-      xstride = a->dim[0].stride;
       xcount = a->dim[0].ubound + 1 - a->dim[0].lbound;
     }
+
+  assert(count == b->dim[0].ubound + 1 - b->dim[0].lbound);
+
   if (GFC_DESCRIPTOR_RANK (b) == 1)
     {
-      bstride = b->dim[0].stride;
-      assert(count == b->dim[0].ubound + 1 - b->dim[0].lbound);
-      ystride = 0;
-      rystride = 0;
+      /* Treat it as a column matrix B[count,1] */
+      bxstride = b->dim[0].stride;
+
+      /* bystride should never be used for 1-dimensional b.
+	 in case it is we want it to cause a segfault, rather than
+	 an incorrect result. */
+      bystride = 0xDEADBEEF; 
       ycount = 1;
     }
   else
     {
-      bstride = b->dim[0].stride;
-      assert(count == b->dim[0].ubound + 1 - b->dim[0].lbound);
-      ystride = b->dim[1].stride;
+      bxstride = b->dim[0].stride;
+      bystride = b->dim[1].stride;
       ycount = b->dim[1].ubound + 1 - b->dim[1].lbound;
     }
 
-  for (y = 0; y < ycount; y++)
+  assert (a->base == 0);
+  assert (b->base == 0);
+  assert (retarray->base == 0);
+
+  abase = a->data;
+  bbase = b->data;
+  dest = retarray->data;
+
+  if (rxstride == 1 && axstride == 1 && bxstride == 1)
     {
-      for (x = 0; x < xcount; x++)
-        {
-          /* Do the summation for this element.  For real and integer types
-             this is the same as DOT_PRODUCT.  For complex types we use do
-             a*b, not conjg(a)*b.  */
-          pa = abase;
-          pb = bbase;
-          res = 0;
-
-          for (n = 0; n < count; n++)
-            {
-              res += *pa * *pb;
-              pa += astride;
-              pb += bstride;
-            }
-
-          *dest = res;
-
-          dest += rxstride;
-          abase += xstride;
-        }
-      abase -= xstride * xcount;
-      bbase += ystride;
-      dest += rystride - (rxstride * xcount);
+      GFC_COMPLEX_8 *bbase_y;
+      GFC_COMPLEX_8 *dest_y;
+      GFC_COMPLEX_8 *abase_n;
+      GFC_COMPLEX_8 bbase_yn;
+
+      memset (dest, 0, (sizeof (GFC_COMPLEX_8) * size0(retarray)));
+
+      for (y = 0; y < ycount; y++)
+	{
+	  bbase_y = bbase + y*bystride;
+	  dest_y = dest + y*rystride;
+	  for (n = 0; n < count; n++)
+	    {
+	      abase_n = abase + n*aystride;
+	      bbase_yn = bbase_y[n];
+	      for (x = 0; x < xcount; x++)
+		{
+		  dest_y[x] += abase_n[x] * bbase_yn;
+		}
+	    }
+	}
+    }
+  else
+    {
+      for (y = 0; y < ycount; y++)
+	for (x = 0; x < xcount; x++)
+	  dest[x*rxstride + y*rystride] = (GFC_COMPLEX_8)0;
+
+      for (y = 0; y < ycount; y++)
+	for (n = 0; n < count; n++)
+	  for (x = 0; x < xcount; x++)
+	    /* dest[x,y] += a[x,n] * b[n,y] */
+	    dest[x*rxstride + y*rystride] += abase[x*axstride + n*aystride] * bbase[n*bxstride + y*bystride];
     }
 }