* gcc.c-torture/execute/pr39228.x: New.

[pf3gnuchains/gcc-fork.git] / gcc / tree-vect-transform.c

diff --git a/gcc/tree-vect-transform.c b/gcc/tree-vect-transform.c
index 2db0167..abb33e2 100644 (file)
--- a/gcc/tree-vect-transform.c
+++ b/gcc/tree-vect-transform.c
@@ -1,5 +1,6 @@
 /* Transformation Utilities for Loop Vectorization.
-   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
+   Free Software Foundation, Inc.
    Contributed by Dorit Naishlos <dorit@il.ibm.com>
 
 This file is part of GCC.
@@ -122,7 +123,6 @@ vect_estimate_min_profitable_iters (loop_vec_info loop_vinfo)
   int vec_outside_cost = 0;
   int scalar_single_iter_cost = 0;
   int scalar_outside_cost = 0;
-  bool runtime_test = false;
   int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
   basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
@@ -141,15 +141,7 @@ vect_estimate_min_profitable_iters (loop_vec_info loop_vinfo)
       return 0;
     }
 
-  /* If the number of iterations is unknown, or the
-     peeling-for-misalignment amount is unknown, we will have to generate
-     a runtime test to test the loop count against the threshold.    */
-  if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
-      || (byte_misalign < 0))
-    runtime_test = true;
-
   /* Requires loop versioning tests to handle misalignment.  */
-
   if (VEC_length (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo)))
     {
       /*  FIXME: Make cost depend on complexity of individual check.  */
@@ -240,12 +232,11 @@ vect_estimate_min_profitable_iters (loop_vec_info loop_vinfo)
                  "peeling for alignment is unknown .");
 
       /* If peeled iterations are unknown, count a taken branch and a not taken
-        branch per peeled loop. Even if scalar loop iterations are known, 
-        vector iterations are not known since peeled prologue iterations are
-        not known. Hence guards remain the same.  */
+         branch per peeled loop. Even if scalar loop iterations are known,
+         vector iterations are not known since peeled prologue iterations are
+         not known. Hence guards remain the same.  */
       peel_guard_costs +=  2 * (TARG_COND_TAKEN_BRANCH_COST
-                              + TARG_COND_NOT_TAKEN_BRANCH_COST);
-
+                              + TARG_COND_NOT_TAKEN_BRANCH_COST);
     }
   else 
     {
@@ -337,7 +328,12 @@ vect_estimate_min_profitable_iters (loop_vec_info loop_vinfo)
      conditions/branch directions.  Change the estimates below to
      something more reasonable.  */
 
-  if (runtime_test)
+  /* If the number of iterations is known and we do not do versioning, we can
+     decide whether to vectorize at compile time. Hence the scalar version
+     do not carry cost model guard costs.  */
+  if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
+      || VEC_length (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo))
+      || VEC_length (ddr_p, LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo)))
     {
       /* Cost model check occurs at versioning.  */
       if (VEC_length (gimple, LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo))
@@ -345,8 +341,8 @@ vect_estimate_min_profitable_iters (loop_vec_info loop_vinfo)
        scalar_outside_cost += TARG_COND_NOT_TAKEN_BRANCH_COST;
       else
        {
-         /* Cost model occurs at prologue generation.  */
-         if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo))
+         /* Cost model check occurs at prologue generation.  */
+         if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) < 0)
            scalar_outside_cost += 2 * TARG_COND_TAKEN_BRANCH_COST
              + TARG_COND_NOT_TAKEN_BRANCH_COST;
          /* Cost model check occurs at epilogue generation.  */