re PR tree-optimization/48172 (incorrect vectorization of loop in GCC 4.5.* with...

2011-05-13  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/48172
	* tree-vect-loop-manip.c (vect_vfa_segment_size): Avoid
	multiplying by number of iterations for equal step.
	(vect_create_cond_for_alias_checks): Likewise.

From-SVN: r173725

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4c145c8911f743c872263aaf5513a2ea1932378a..bd8db53a3f7532c8a74d59a07a2386e2e77055a4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2011-05-13  Richard Guenther  <rguenther@suse.de>
+
+       PR tree-optimization/48172
+       * tree-vect-loop-manip.c (vect_vfa_segment_size): Avoid
+       multiplying by number of iterations for equal step.
+       (vect_create_cond_for_alias_checks): Likewise.
+
 2011-05-13  Andreas Schwab  <schwab@redhat.com>
 
        * configure.ac: Use AS_HELP_STRING throughout.

diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
index d990e7f45f84bc0437408104ab3a83891d871e50..b691cd2a0c069c55b08e21f1f5d4b099594e6c15 100644 (file)
--- a/gcc/tree-vect-loop-manip.c
+++ b/gcc/tree-vect-loop-manip.c
@@ -2353,23 +2353,18 @@ vect_create_cond_for_align_checks (loop_vec_info loop_vinfo,
 
    Input:
      DR: The data reference.
-     VECT_FACTOR: vectorization factor.
-     SCALAR_LOOP_NITERS: number of iterations.
+     LENGTH_FACTOR: segment length to consider.
 
    Return an expression whose value is the size of segment which will be
    accessed by DR.  */
 
 static tree
-vect_vfa_segment_size (struct data_reference *dr, int vect_factor,
-                      tree scalar_loop_niters)
+vect_vfa_segment_size (struct data_reference *dr, tree length_factor)
 {
   tree segment_length;
   segment_length = size_binop (MULT_EXPR,
                               fold_convert (sizetype, DR_STEP (dr)),
-                              size_int (vect_factor));
-  segment_length = size_binop (MULT_EXPR,
-                              segment_length,
-                              fold_convert (sizetype, scalar_loop_niters));
+                              fold_convert (sizetype, length_factor));
   if (vect_supportable_dr_alignment (dr, false)
         == dr_explicit_realign_optimized)
     {
@@ -2417,7 +2412,7 @@ vect_create_cond_for_alias_checks (loop_vec_info loop_vinfo,
 
   ddr_p ddr;
   unsigned int i;
-  tree part_cond_expr;
+  tree part_cond_expr, length_factor;
 
   /* Create expression
      ((store_ptr_0 + store_segment_length_0) < load_ptr_0)
@@ -2465,10 +2460,12 @@ vect_create_cond_for_alias_checks (loop_vec_info loop_vinfo,
         vect_create_addr_base_for_vector_ref (stmt_b, cond_expr_stmt_list,
                                              NULL_TREE, loop);
 
-      segment_length_a = vect_vfa_segment_size (dr_a, vect_factor,
-                                               scalar_loop_iters);
-      segment_length_b = vect_vfa_segment_size (dr_b, vect_factor,
-                                               scalar_loop_iters);
+      if (!operand_equal_p (DR_STEP (dr_a), DR_STEP (dr_b), 0))
+       length_factor = scalar_loop_iters;
+      else
+       length_factor = size_int (vect_factor);
+      segment_length_a = vect_vfa_segment_size (dr_a, length_factor);
+      segment_length_b = vect_vfa_segment_size (dr_b, length_factor);
 
       if (vect_print_dump_info (REPORT_DR_DETAILS))
        {