Fix PR tree-optimization / 31946 :

Fix PR tree-optimization / 31946 :

[Ramana Radhakrishnan]

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Hi,

I am currently testing this patch to fix PR 31946 for less stricter
peeling-for-alignment.  It fixes the peeling limits for the testcases
mentioned in the PR.  I am bootstrapping on an x86-32 box currently and
running the regression suite.


cheers
Ramana


-- 
Ramana Radhakrishnan

:ADDPATCH autovect: PR tree-optimization/31946

2007-08-03  Ramana Radhakrishnan  <ramana.r@gmail.com>

	PR tree-optimization/31946
	* tree-vect-analyze.c (return_peeling_factor_for_data_reference):
	New. Refactor code for calculation of peeling factor for a data
	reference.
	(vect_enhance_data_refs_alignment): Refactor
	calculation of peeling factor. Peel by data reference that allows
	for the maximum peeling factor.

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Index: ChangeLog
===================================================================
--- ChangeLog	(revision 127165)
+++ ChangeLog	(working copy)
@@ -1,3 +1,12 @@
+2007-08-03  Ramana Radhakrishnan  <ramana.r@gmail.com>
+
+	PR tree-optimization/31946
+	* tree-vect-analyze.c (return_peeling_factor_for_data_reference): New. Refactor 
+	code for calculation of peeling factor for a data reference.
+	(vect_enhance_data_refs_alignment): Refactor 
+	calculation of peeling factor. Peel by data reference that allows 
+	for the maximum peeling factor. 
+	
 2007-08-02  Steve Ellcey  <sje@cup.hp.com>
 
 	* config/ia64/constraints.md ("U"): Make constraint vector only.
Index: tree-vect-analyze.c
===================================================================
--- tree-vect-analyze.c	(revision 127165)
+++ tree-vect-analyze.c	(working copy)
@@ -1449,6 +1449,52 @@
   return true;
 }
 
+/* Function that returns the peeling factor for a given data reference. The peeling 
+   factor cannot be determined as given in the comment above vect_enhance_data_refs_alignment.  
+*/
+   
+
+
+static int
+return_peeling_factor_for_data_reference (struct data_reference * dr0)
+{
+  tree stmt = DR_STMT (dr0);
+  stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+  tree vectype = STMT_VINFO_VECTYPE (stmt_info);
+  int nelements = TYPE_VECTOR_SUBPARTS (vectype);
+  int mis;
+  int npeel = 0;
+ 
+  if (vect_print_dump_info (REPORT_DETAILS))
+      fprintf (vect_dump, "--> In return peeling factor for data references \n");
+  
+  if (known_alignment_for_access_p (dr0))
+    {
+      /* Since it's known at compile time, compute the number of iterations
+         in the peeled loop (the peeling factor) for use in updating
+         DR_MISALIGNMENT values.  The peeling factor is the vectorization
+         factor minus the misalignment as an element count.  */
+      mis = DR_MISALIGNMENT (dr0);
+      mis /= GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr0))));
+      npeel = nelements - mis;
+      
+      /* For interleaved data access every iteration accesses all the 
+         members of the group, therefore we divide the number of iterations
+         by the group size.  */
+      stmt_info = vinfo_for_stmt (DR_STMT (dr0));	  
+      if (DR_GROUP_FIRST_DR (stmt_info))
+        npeel /= DR_GROUP_SIZE (stmt_info);
+      
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "Peeling factor is %d", npeel);
+    }
+  
+  return npeel;
+  
+}
+
+
+
 /* Function vect_enhance_data_refs_alignment
 
    This pass will use loop versioning and loop peeling in order to enhance
@@ -1547,6 +1593,8 @@
   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
   enum dr_alignment_support supportable_dr_alignment;
   struct data_reference *dr0 = NULL;
+  int max_peelfactor_sofar = 0;
+  int current_peelfactor = 0;
   struct data_reference *dr;
   unsigned int i;
   bool do_peeling = false;
@@ -1611,11 +1659,16 @@
       if (!DR_IS_READ (dr) && !aligned_access_p (dr))
         {
 	  do_peeling = vector_alignment_reachable_p (dr);
-	  if (do_peeling)
-	    dr0 = dr;
+          current_peelfactor = return_peeling_factor_for_data_reference (dr);
+
+          if (do_peeling && (current_peelfactor > max_peelfactor_sofar))
+            {
+              dr0 = dr;
+              max_peelfactor_sofar = current_peelfactor;
+            }
+
 	  if (!do_peeling && vect_print_dump_info (REPORT_DETAILS))
             fprintf (vect_dump, "vector alignment may not be reachable");
-	  break;
 	}
     }
 
@@ -1627,34 +1680,17 @@
 
   if (do_peeling)
     {
-      int mis;
-      int npeel = 0;
+
+      int npeel = max_peelfactor_sofar;
       tree stmt = DR_STMT (dr0);
       stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
-      tree vectype = STMT_VINFO_VECTYPE (stmt_info);
-      int nelements = TYPE_VECTOR_SUBPARTS (vectype);
 
-      if (known_alignment_for_access_p (dr0))
-        {
-          /* Since it's known at compile time, compute the number of iterations
-             in the peeled loop (the peeling factor) for use in updating
-             DR_MISALIGNMENT values.  The peeling factor is the vectorization
-             factor minus the misalignment as an element count.  */
-          mis = DR_MISALIGNMENT (dr0);
-          mis /= GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr0))));
-          npeel = nelements - mis;
 
-	  /* For interleaved data access every iteration accesses all the 
-	     members of the group, therefore we divide the number of iterations
-	     by the group size.  */
-	  stmt_info = vinfo_for_stmt (DR_STMT (dr0));	  
-	  if (DR_GROUP_FIRST_DR (stmt_info))
-	    npeel /= DR_GROUP_SIZE (stmt_info);
 
-          if (vect_print_dump_info (REPORT_DETAILS))
-            fprintf (vect_dump, "Try peeling by %d", npeel);
-        }
+      if (vect_print_dump_info (REPORT_DETAILS))
+        fprintf (vect_dump, "Try peeling by %d", npeel);
 
+
       /* Ensure that all data refs can be vectorized after the peel.  */
       for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
         {

Re: Fix PR tree-optimization / 31946 :

[Ramana Radhakrishnan]

Hi,

>
> I am currently testing this patch to fix PR 31946 for less stricter
> peeling-for-alignment.  It fixes the peeling limits for the testcases
> mentioned in the PR.  I am bootstrapping on an x86-32 box currently and
> running the regression suite.

The patch broke bootstrap for fortran. I've tested an updated patch
that fixes that . However the testsuite needs to be fixed for the
fallout with this patch as it allows for vectorization with different
peeling limits for the testcases mentioned in the PR .

I'll submit a complete patch once I have worked through the test fails
but that will have to be much later this the evening.

cheers
Raman
>
>
> cheers
> Ramana
>
>
> --
> Ramana Radhakrishnan
>
> :ADDPATCH autovect: PR tree-optimization/31946
>
> 2007-08-03  Ramana Radhakrishnan  <ramana.r@gmail.com>
>
>         PR tree-optimization/31946
>         * tree-vect-analyze.c (return_peeling_factor_for_data_reference):
>         New. Refactor code for calculation of peeling factor for a data
>         reference.
>         (vect_enhance_data_refs_alignment): Refactor
>         calculation of peeling factor. Peel by data reference that allows
>         for the maximum peeling factor.
>
>


-- 
Ramana Radhakrishnan