Disallow negative steps in vectorizer.

gcc/

2010-10-02  H.J. Lu  <hongjiu.lu@intel.com>

	PR tree-optimization/45720
	PR tree-optimization/45764
	* tree-vect-data-refs.c (vect_analyze_data_ref_access):
	Don't accept backwards consecutive accesses.
	(vect_create_data_ref_ptr): Disallow negative steps.

	* tree-vect-stmts.c (vectorizable_store): Allow negative steps.
	(perm_mask_for_reverse): Removed.
	(reverse_vec_elements): Likewise.
	(vectorizable_load): Don't hanle negative steps.

gcc/testsuite/

2010-10-02  H.J. Lu  <hongjiu.lu@intel.com>

	PR tree-optimization/45720
	PR tree-optimization/45764
	* g++.dg/torture/pr45764.C: New.

	* gcc.dg/vect/pr43432.c: Xfail.
	* gcc.dg/vect/vect-114.c: Likewise.
	* gcc.dg/vect/vect-15.c: Likewise.

From-SVN: r164914

8 files changed, 52 insertions, 116 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1fa311d..41190f9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
+2010-10-02  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR tree-optimization/45720
+	PR tree-optimization/45764
+	* tree-vect-data-refs.c (vect_analyze_data_ref_access):
+	Don't accept backwards consecutive accesses.
+	(vect_create_data_ref_ptr): Disallow negative steps.
+
+	* tree-vect-stmts.c (vectorizable_store): Allow negative steps.
+	(perm_mask_for_reverse): Removed.
+	(reverse_vec_elements): Likewise.
+	(vectorizable_load): Don't hanle negative steps.
+
 2010-10-02  Jan Hubicka  <jh@suse.cz>
 
 	* tree-ssa-ccp.c (ccp_fold_stmt): Fold away OBJ_TYPE_REF when
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1745ff0..3319f7a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,13 @@
+2010-10-02  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR tree-optimization/45720
+	PR tree-optimization/45764
+	* g++.dg/torture/pr45764.C: New.
+
+	* gcc.dg/vect/pr43432.c: Xfail.
+	* gcc.dg/vect/vect-114.c: Likewise.
+	* gcc.dg/vect/vect-15.c: Likewise.
+
 2010-10-02  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
 
 	* gcc.dg/torture/pr45678-1.c: Add -fno-common to options on 32-bit
diff --git a/gcc/testsuite/g++.dg/torture/pr45764.C b/gcc/testsuite/g++.dg/torture/pr45764.C
new file mode 100644
index 0000000..56f32be
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr45764.C
@@ -0,0 +1,25 @@
+// { dg-do run }
+
+int result[64][16];
+
+int main()
+{
+        double dbuf[1000] = {0.0};
+        int ibuf[900];
+
+        double d1 = 0.0;
+        double d2 = 0.0;
+        for (int i = 0; i < 900; ++i) {
+                ibuf[i] = int(d2 - d1);
+                d1 += dbuf[i];
+                d2 += dbuf[i + 64];
+        }
+
+        for (int i = 0; i < 64; ++i) {
+                for (int j = 0; j < 8; ++j) {
+                        result[i][     j] = ibuf[64 - i + 64 * j];
+                        result[i][15 - j] = ibuf[     i + 64 * j];
+                }
+        }
+	return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/vect/pr43432.c b/gcc/testsuite/gcc.dg/vect/pr43432.c
index 18c0dba..a979a5c 100644
--- a/gcc/testsuite/gcc.dg/vect/pr43432.c
+++ b/gcc/testsuite/gcc.dg/vect/pr43432.c
@@ -10,5 +10,5 @@ int len){
         dst[i] = src0[i] * src1[-i];
 }
 
-/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target { vect_perm } } } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { xfail { vect_perm } } } } */
 /* { dg-final { cleanup-tree-dump "vect" } } */
diff --git a/gcc/testsuite/gcc.dg/vect/vect-114.c b/gcc/testsuite/gcc.dg/vect/vect-114.c
index f9132ac..4964a83 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-114.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-114.c
@@ -35,6 +35,6 @@ int main (void)
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 0 loops" 1 "vect" { target { ! vect_perm } } } } */
-/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target vect_perm } } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { xfail vect_perm } } } */
 /* { dg-final { cleanup-tree-dump "vect" } } */
 
diff --git a/gcc/testsuite/gcc.dg/vect/vect-15.c b/gcc/testsuite/gcc.dg/vect/vect-15.c
index 87853c1..d4621d3 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-15.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-15.c
@@ -35,5 +35,5 @@ int main (void)
   return main1 ();
 }
 
-/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target vect_perm } } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { xfail vect_perm } } } */
 /* { dg-final { cleanup-tree-dump "vect" } } */
diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c
index 7182513..0d1e338 100644
--- a/gcc/tree-vect-data-refs.c
+++ b/gcc/tree-vect-data-refs.c
@@ -2287,9 +2287,7 @@ vect_analyze_data_ref_access (struct data_reference *dr)
     }
 
   /* Consecutive?  */
-  if (!tree_int_cst_compare (step, TYPE_SIZE_UNIT (scalar_type))
-      || (dr_step < 0
-	  && !compare_tree_int (TYPE_SIZE_UNIT (scalar_type), -dr_step)))
+  if (!tree_int_cst_compare (step, TYPE_SIZE_UNIT (scalar_type)))
     {
       /* Mark that it is not interleaving.  */
       DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt)) = NULL;
@@ -2972,7 +2970,6 @@ vect_create_data_ref_ptr (gimple stmt, struct loop *at_loop,
   tree vptr;
   gimple_stmt_iterator incr_gsi;
   bool insert_after;
-  bool negative;
   tree indx_before_incr, indx_after_incr;
   gimple incr;
   tree step;
@@ -3005,7 +3002,6 @@ vect_create_data_ref_ptr (gimple stmt, struct loop *at_loop,
     *inv_p = true;
   else
     *inv_p = false;
-  negative = tree_int_cst_compare (step, size_zero_node) < 0;
 
   /* Create an expression for the first address accessed by this load
      in LOOP.  */
@@ -3164,8 +3160,6 @@ vect_create_data_ref_ptr (gimple stmt, struct loop *at_loop,
 	 LOOP is zero. In this case the step here is also zero.  */
       if (*inv_p)
 	step = size_zero_node;
-      else if (negative)
-	step = fold_build1 (NEGATE_EXPR, TREE_TYPE (step), step);
 
       standard_iv_increment_position (loop, &incr_gsi, &insert_after);
 
diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
index b120dc6..a758410 100644
--- a/gcc/tree-vect-stmts.c
+++ b/gcc/tree-vect-stmts.c
@@ -3145,13 +3145,6 @@ vectorizable_store (gimple stmt, gimple_stmt_iterator *gsi, gimple *vec_stmt,
   if (!STMT_VINFO_DATA_REF (stmt_info))
     return false;
 
-  if (tree_int_cst_compare (DR_STEP (dr), size_zero_node) < 0)
-    {
-      if (vect_print_dump_info (REPORT_DETAILS))
-        fprintf (vect_dump, "negative step for store.");
-      return false;
-    }
-
   if (STMT_VINFO_STRIDED_ACCESS (stmt_info))
     {
       strided_store = true;
@@ -3432,68 +3425,6 @@ vectorizable_store (gimple stmt, gimple_stmt_iterator *gsi, gimple *vec_stmt,
   return true;
 }
 
-/* Given a vector type VECTYPE returns a builtin DECL to be used
-   for vector permutation and stores a mask into *MASK that implements
-   reversal of the vector elements.  If that is impossible to do
-   returns NULL (and *MASK is unchanged).  */
-
-static tree
-perm_mask_for_reverse (tree vectype, tree *mask)
-{
-  tree builtin_decl;
-  tree mask_element_type, mask_type;
-  tree mask_vec = NULL;
-  int i;
-  int nunits;
-  if (!targetm.vectorize.builtin_vec_perm)
-    return NULL;
-
-  builtin_decl = targetm.vectorize.builtin_vec_perm (vectype,
-                                                     &mask_element_type);
-  if (!builtin_decl || !mask_element_type)
-    return NULL;
-
-  mask_type = get_vectype_for_scalar_type (mask_element_type);
-  nunits = TYPE_VECTOR_SUBPARTS (vectype);
-  if (TYPE_VECTOR_SUBPARTS (vectype) != TYPE_VECTOR_SUBPARTS (mask_type))
-    return NULL;
-
-  for (i = 0; i < nunits; i++)
-    mask_vec = tree_cons (NULL, build_int_cst (mask_element_type, i), mask_vec);
-  mask_vec = build_vector (mask_type, mask_vec);
-
-  if (!targetm.vectorize.builtin_vec_perm_ok (vectype, mask_vec))
-    return NULL;
-  if (mask)
-    *mask = mask_vec;
-  return builtin_decl;
-}
-
-/* Given a vector variable X, that was generated for the scalar LHS of
-   STMT, generate instructions to reverse the vector elements of X,
-   insert them a *GSI and return the permuted vector variable.  */
-
-static tree
-reverse_vec_elements (tree x, gimple stmt, gimple_stmt_iterator *gsi)
-{
-  tree vectype = TREE_TYPE (x);
-  tree mask_vec, builtin_decl;
-  tree perm_dest, data_ref;
-  gimple perm_stmt;
-
-  builtin_decl = perm_mask_for_reverse (vectype, &mask_vec);
-
-  perm_dest = vect_create_destination_var (gimple_assign_lhs (stmt), vectype);
-
-  /* Generate the permute statement.  */
-  perm_stmt = gimple_build_call (builtin_decl, 3, x, x, mask_vec);
-  data_ref = make_ssa_name (perm_dest, perm_stmt);
-  gimple_call_set_lhs (perm_stmt, data_ref);
-  vect_finish_stmt_generation (stmt, perm_stmt, gsi);
-
-  return data_ref;
-}
-
 /* vectorizable_load.
 
    Check if STMT reads a non scalar data-ref (array/pointer/structure) that
@@ -3536,7 +3467,6 @@ vectorizable_load (gimple stmt, gimple_stmt_iterator *gsi, gimple *vec_stmt,
   gimple first_stmt;
   tree scalar_type;
   bool inv_p;
-  bool negative;
   bool compute_in_loop = false;
   struct loop *at_loop;
   int vec_num;
@@ -3599,14 +3529,6 @@ vectorizable_load (gimple stmt, gimple_stmt_iterator *gsi, gimple *vec_stmt,
   if (!STMT_VINFO_DATA_REF (stmt_info))
     return false;
 
-  negative = tree_int_cst_compare (DR_STEP (dr), size_zero_node) < 0;
-  if (negative && ncopies > 1)
-    {
-      if (vect_print_dump_info (REPORT_DETAILS))
-        fprintf (vect_dump, "multiple types with negative step.");
-      return false;
-    }
-
   scalar_type = TREE_TYPE (DR_REF (dr));
   mode = TYPE_MODE (vectype);
 
@@ -3641,25 +3563,6 @@ vectorizable_load (gimple stmt, gimple_stmt_iterator *gsi, gimple *vec_stmt,
 	return false;
     }
 
-  if (negative)
-    {
-      gcc_assert (!strided_load);
-      alignment_support_scheme = vect_supportable_dr_alignment (dr, false);
-      if (alignment_support_scheme != dr_aligned
-	  && alignment_support_scheme != dr_unaligned_supported)
-	{
-	  if (vect_print_dump_info (REPORT_DETAILS))
-	    fprintf (vect_dump, "negative step but alignment required.");
-	  return false;
-	}
-      if (!perm_mask_for_reverse (vectype, NULL))
-	{
-	  if (vect_print_dump_info (REPORT_DETAILS))
-	    fprintf (vect_dump, "negative step and reversing not supported.");
-	  return false;
-	}
-    }
-
   if (!vec_stmt) /* transformation not required.  */
     {
       STMT_VINFO_TYPE (stmt_info) = load_vec_info_type;
@@ -3834,9 +3737,6 @@ vectorizable_load (gimple stmt, gimple_stmt_iterator *gsi, gimple *vec_stmt,
   else
     at_loop = loop;
 
-  if (negative)
-    offset = size_int (-TYPE_VECTOR_SUBPARTS (vectype) + 1);
-
   prev_stmt_info = NULL;
   for (j = 0; j < ncopies; j++)
     {
@@ -4025,12 +3925,6 @@ vectorizable_load (gimple stmt, gimple_stmt_iterator *gsi, gimple *vec_stmt,
 		gcc_unreachable (); /* FORNOW. */
 	    }
 
-	  if (negative)
-	    {
-	      new_temp = reverse_vec_elements (new_temp, stmt, gsi);
-	      new_stmt = SSA_NAME_DEF_STMT (new_temp);
-	    }
-
 	  /* Collect vector loads and later create their permutation in
 	     vect_transform_strided_load ().  */
           if (strided_load || slp_perm)