re PR tree-optimization/37539 (Hang for -O3)

	PR tree-optimization/37539
	* tree-vect-transform.c (vect_transform_strided_load): Save vector
	statement in related statement field only for the first load of the
	group of loads with the same data reference.

From-SVN: r140522

gcc/ChangeLog

+2008-09-21  Ira Rosen  <irar@il.ibm.com>
+
+	PR tree-optimization/37539
+	* tree-vect-transform.c (vect_transform_strided_load): Save vector
+	statement in related statement field only for the first load of the
+	group of loads with the same data reference.
+
 2008-09-20  Adam Nemet  <anemet@caviumnetworks.com>
 
 	* config/mips/mips.h (TUNE_OCTEON): New macro.

gcc/testsuite/ChangeLog

+2008-09-21  Ira Rosen  <irar@il.ibm.com>
+
+	PR tree-optimization/37539
+	* gcc.dg/vect/pr37539.c: New test.
+
 2008-09-20  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR rtl-optimization/33642

gcc/testsuite/gcc.dg/vect/pr37539.c

+/* { dg-require-effective-target vect_int } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+__attribute__ ((noinline)) void
+ayuv2yuyv_ref (int *d, int *src, int n)
+{
+  char *dest = (char *)d;
+  int i;
+
+  for(i=0;i<n/2;i++){
+    dest[i*4 + 0] = (src[i*2 + 0])>>16;
+    dest[i*4 + 1] = (src[i*2 + 1])>>8;
+    dest[i*4 + 2] = (src[i*2 + 0])>>16;
+    dest[i*4 + 3] = (src[i*2 + 0])>>0;
+  }
+
+  /* Check results.  */
+  for(i=0;i<n/2;i++){
+   if (dest[i*4 + 0] != (src[i*2 + 0])>>16
+       || dest[i*4 + 1] != (src[i*2 + 1])>>8
+       || dest[i*4 + 2] != (src[i*2 + 0])>>16
+       || dest[i*4 + 3] != (src[i*2 + 0])>>0) 
+     abort();
+  }
+}
+
+int main ()
+{
+  int d[256], src[128], i;
+ 
+  for (i = 0; i < 128; i++)
+    src[i] = i; 
+  
+  ayuv2yuyv_ref(d, src, 128);
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 2 "vect" { target vect_strided_wide } } } */
+/* { dg-final { cleanup-tree-dump "vect" } } */
+
+
+

gcc/tree-vect-transform.c

@@ -5947,17 +5947,24 @@ vect_transform_strided_load (gimple stmt, VEC(tree,heap) *dr_chain, int size,
 	    STMT_VINFO_VEC_STMT (vinfo_for_stmt (next_stmt)) = new_stmt;
 	  else
             {
-	      gimple prev_stmt =
-		STMT_VINFO_VEC_STMT (vinfo_for_stmt (next_stmt));
-	      gimple rel_stmt =
-		STMT_VINFO_RELATED_STMT (vinfo_for_stmt (prev_stmt));
-	      while (rel_stmt)
-		{
-		  prev_stmt = rel_stmt;
-		  rel_stmt = STMT_VINFO_RELATED_STMT (vinfo_for_stmt (rel_stmt));
-		}
-	      STMT_VINFO_RELATED_STMT (vinfo_for_stmt (prev_stmt)) = new_stmt;
+              if (!DR_GROUP_SAME_DR_STMT (vinfo_for_stmt (next_stmt)))
+                {
+ 	          gimple prev_stmt =
+		    STMT_VINFO_VEC_STMT (vinfo_for_stmt (next_stmt));
+	          gimple rel_stmt =
+		    STMT_VINFO_RELATED_STMT (vinfo_for_stmt (prev_stmt));
+	          while (rel_stmt)
+		    {
+		      prev_stmt = rel_stmt;
+		      rel_stmt = 
+                        STMT_VINFO_RELATED_STMT (vinfo_for_stmt (rel_stmt));
+		    }
+
+  	          STMT_VINFO_RELATED_STMT (vinfo_for_stmt (prev_stmt)) = 
+                    new_stmt;
+                }
             }
+
 	  next_stmt = DR_GROUP_NEXT_DR (vinfo_for_stmt (next_stmt));
 	  gap_count = 1;
 	  /* If NEXT_STMT accesses the same DR as the previous statement,