tree-vectorizer.h (unknown_alignment_for_access_p): Replaced by known_alignment_for_access_p.

        * tree-vectorizer.h (unknown_alignment_for_access_p): Replaced by
        known_alignment_for_access_p.
        (known_alignment_for_access_p): New.
        (do_peeling_for_alignment): Field made int instead of bool and renamed
        to peeling_for_alignment.
        (LOOP_DO_PEELING_FOR_ALIGNMENT): Renamed to LOOP_PEELING_FOR_ALIGNMENT.
        * tree-vect-analyze.c (vect_determine_vectorization_factor): New. This
        functionality used to be in vect_analyze_operations.
        (vect_analyze_operations): Code to determine vectorization factor was
        moved to vect_determine_vectorization_factor.
        (vect_enhance_data_refs_alignment): Update to correct alignment when it
        is known instead of -1.  Set LOOP_PEELING_FOR_ALIGNMENT to peeling
        factor.
        (vect_analyze_loop): Call vect_determine_vectorization_factor (used to
        be part of vect_analyze_operations).
        * tree-vectorizer.c (slpeel_tree_peel_loop_to_edge): Use fold when
        creating the guard condition, as the number of iterations may be
        constant.
        (slpeel_tree_peel_loop_to_edge): Use new name of
        LOOP_DO_PEELING_FOR_ALIGNMENT. Set it to 0 instead of false.
        * tree-vect-transform.c (vect_gen_niters_for_prolog_loop): Handle known
        alignment case more efficiently. Use LOOP_PEELING_FOR_ALIGNMENT.
        (vect_do_peeling_for_alignment): Use fold.
        (vect_transform_loop): Use new name of LOOP_DO_PEELING_FOR_ALIGNMENT.

        (vect_update_inits_of_dr): Renamed to
        vect_update_init_of_dr.
        (vect_update_inits_of_drs): Use new name of vect_update_inits_of_dr.
        (vectorizable_store): Fix assertion to use == instead of =.

From-SVN: r96526

gcc/ChangeLog

+2005-03-15  Dorit Naishlos  <dorit@il.ibm.com>
+
+	* tree-vectorizer.h (unknown_alignment_for_access_p): Replaced by
+	known_alignment_for_access_p.
+	(known_alignment_for_access_p): New.
+	(do_peeling_for_alignment): Field made int instead of bool and renamed
+	to peeling_for_alignment.
+	(LOOP_DO_PEELING_FOR_ALIGNMENT): Renamed to LOOP_PEELING_FOR_ALIGNMENT.
+	* tree-vect-analyze.c (vect_determine_vectorization_factor): New. This
+	functionality used to be in vect_analyze_operations.
+	(vect_analyze_operations): Code to determine vectorization factor was
+	moved to vect_determine_vectorization_factor.
+	(vect_enhance_data_refs_alignment): Update to correct alignment when it
+	is known instead of -1.  Set LOOP_PEELING_FOR_ALIGNMENT to peeling
+	factor.
+	(vect_analyze_loop): Call vect_determine_vectorization_factor (used to
+	be part of vect_analyze_operations).
+	* tree-vectorizer.c (slpeel_tree_peel_loop_to_edge): Use fold when
+	creating the guard condition, as the number of iterations may be
+	constant.
+	(slpeel_tree_peel_loop_to_edge): Use new name of
+	LOOP_DO_PEELING_FOR_ALIGNMENT. Set it to 0 instead of false.
+	* tree-vect-transform.c (vect_gen_niters_for_prolog_loop): Handle known
+	alignment case more efficiently. Use LOOP_PEELING_FOR_ALIGNMENT.
+	(vect_do_peeling_for_alignment): Use fold.
+	(vect_transform_loop): Use new name of LOOP_DO_PEELING_FOR_ALIGNMENT.
+
+	(vect_update_inits_of_dr): Renamed to
+	vect_update_init_of_dr.
+	(vect_update_inits_of_drs): Use new name of vect_update_inits_of_dr.
+	(vectorizable_store): Fix assertion to use == instead of =.
+
 2005-03-15  Daniel Jacobowitz  <dan@codesourcery.com>
 
 	* config/arm/arm.h (CONDITIONAL_REGISTER_USAGE): Don't clear

gcc/testsuite/ChangeLog

+2005-03-15  Dorit Naishlos  <dorit@il.ibm.com>
+
+	* gcc.dg/vect/vect-54.c: Now vectorizable on targets that don't support
+	misaligned accesses.
+	* gcc.dg/vect/vect-58.c: Likewise.
+	* gcc.dg/vect/vect-92.c: New.
+	* gcc.dg/vect/vect-93.c: New.
+
 2005-03-15  Feng Wang  <fengwang@nudt.edu.cn>
 
 	PR fortran/18827

gcc/testsuite/gcc.dg/vect/vect-54.c

@@ -50,6 +50,6 @@ int main (void)
   return 0;
 }
 
-/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { xfail vect_no_align } } } */
-/* { dg-final { scan-tree-dump-times "Vectorizing an unaligned access" 2 "vect" { xfail vect_no_align } } } */
-/* { dg-final { scan-tree-dump-times "Alignment of access forced using peeling" 1 "vect" { xfail vect_no_align } } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
+/* { dg-final { scan-tree-dump-times "Vectorizing an unaligned access" 0 "vect" } } */
+/* { dg-final { scan-tree-dump-times "Alignment of access forced using peeling" 1 "vect" } } */

gcc/testsuite/gcc.dg/vect/vect-58.c

@@ -51,6 +51,6 @@ int main (void)
   return 0;
 }
 
-/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { xfail vect_no_align } } } */
-/* { dg-final { scan-tree-dump-times "Vectorizing an unaligned access" 2 "vect" { xfail vect_no_align } } } */
-/* { dg-final { scan-tree-dump-times "Alignment of access forced using peeling" 1 "vect" { xfail vect_no_align } } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
+/* { dg-final { scan-tree-dump-times "Vectorizing an unaligned access" 0 "vect" } } */
+/* { dg-final { scan-tree-dump-times "Alignment of access forced using peeling" 1 "vect" } } */

gcc/testsuite/gcc.dg/vect/vect-92.c

+/* { dg-require-effective-target vect_float } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+#define N 256
+
+typedef float afloat __attribute__ ((__aligned__(16)));
+
+/* known misalignment: same alignment  */
+
+int
+main1 (afloat * __restrict__ pa, afloat * __restrict__ pb, afloat * __restrict__ pc)
+{
+  int i;
+
+  for (i = 0; i < 5; i++)
+    {
+      pa[i+1] = pb[i+1] * pc[i+1];
+    }
+
+  /* check results:  */
+  for (i = 0; i < 5; i++)
+    {
+      if (pa[i+1] != (pb[i+1] * pc[i+1]))
+	abort ();
+    }
+
+  return 0;
+}
+
+int
+main2 (afloat * __restrict__ pa, afloat * __restrict__ pb, afloat * __restrict__ pc)
+{
+  int i;
+
+  for (i = 0; i < 6; i++)
+    {
+      pa[i+1] = pb[i+1] * pc[i+1];
+    }
+
+  /* check results:  */
+  for (i = 0; i < 6; i++)
+    {
+      if (pa[i+1] != (pb[i+1] * pc[i+1]))
+	abort ();
+    }
+
+  return 0;
+}
+
+int
+main3 (afloat * __restrict__ pa, afloat * __restrict__ pb, afloat * __restrict__ pc, int n)
+{
+  int i;
+
+  for (i = 0; i < n; i++)
+    {
+      pa[i+1] = pb[i+1] * pc[i+1];
+    }
+
+  /* check results:  */
+  for (i = 0; i < n; i++)
+    {
+      if (pa[i+1] != (pb[i+1] * pc[i+1]))
+	abort ();
+    }
+
+  return 0;
+}
+
+int main (void)
+{
+  int i;
+  afloat a[N];
+  afloat b[N] = {0,3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48,51,54,57};
+  afloat c[N] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19};
+
+  check_vect ();
+
+  main1 (a,b,c);
+  main2 (a,b,c);
+  main3 (a,b,c,N);
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 3 "vect" } } */
+/* { dg-final { scan-tree-dump-times "Vectorizing an unaligned access" 0 "vect" } } */
+/* { dg-final { scan-tree-dump-times "Alignment of access forced using peeling" 3 "vect" } } */

gcc/testsuite/gcc.dg/vect/vect-93.c

+/* { dg-require-effective-target vect_float } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+#define N 3001
+
+typedef float afloat __attribute__ ((__aligned__(16)));
+
+int
+main1 (float *pa)
+{
+  int i;
+
+  for (i = 0; i < 3001; i++)
+    {
+      pa[i] = 2.0;
+    }
+
+  /* check results:  */
+  for (i = 0; i < 3001; i++)
+    {
+      if (pa[i] != 2.0)
+	abort ();
+    }
+
+  for (i = 1; i <= 10; i++)
+    {
+      pa[i] = 3.0;
+    }
+
+  /* check results:  */
+  for (i = 1; i <= 10; i++)
+    {
+      if (pa[i] != 3.0)
+	abort ();
+    }
+  
+  return 0;
+}
+
+int main (void)
+{
+  int i;
+  afloat a[N];
+  afloat b[N];
+
+  check_vect ();
+
+  /* from bzip2: */
+  for (i=0; i<N; i++) b[i] = i;
+  a[0] = 0;
+  for (i = 1; i <= 256; i++) a[i] = b[i-1];
+
+  /* check results:  */
+  for (i = 1; i <= 256; i++)
+    {
+      if (a[i] != i-1)
+	abort ();
+    }
+  if (a[0] != 0)
+    abort ();
+
+  main1 (a);
+
+  return 0;
+}
+
+/* in main1 */
+/* { dg-final { scan-tree-dump-times "vectorized 2 loops" 1 "vect" } } */
+/* { dg-final { scan-tree-dump-times "Alignment of access forced using peeling" 2 "vect" { target vect_no_align } } } */
+/* { dg-final { scan-tree-dump-times "Alignment of access forced using peeling" 3 "vect" { xfail vect_no_align } } } */
+
+/* in main */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { xfail vect_no_align } } } */
+/* { dg-final { scan-tree-dump-times "Vectorizing an unaligned access" 1 "vect" { xfail vect_no_align } } } */

gcc/tree-vect-transform.c

@@ -64,7 +64,7 @@ static void vect_generate_tmps_on_preheader
 static tree vect_build_loop_niters (loop_vec_info);
 static void vect_update_ivs_after_vectorizer (loop_vec_info, tree, edge); 
 static tree vect_gen_niters_for_prolog_loop (loop_vec_info, tree);
-static void vect_update_inits_of_dr (struct data_reference *, tree niters);
+static void vect_update_init_of_dr (struct data_reference *, tree niters);
 static void vect_update_inits_of_drs (loop_vec_info, tree);
 static void vect_do_peeling_for_alignment (loop_vec_info, struct loops *);
 static void vect_do_peeling_for_loop_bound 
@@ -907,7 +907,7 @@ vectorizable_store (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt)
 
   alignment_support_cheme = vect_supportable_dr_alignment (dr);
   gcc_assert (alignment_support_cheme);
-  gcc_assert (alignment_support_cheme = dr_aligned);  /* FORNOW */
+  gcc_assert (alignment_support_cheme == dr_aligned);  /* FORNOW */
 
   /* Handle use - get the vectorized def from the defining stmt.  */
   vec_oprnd1 = vect_get_vec_def_for_operand (op, stmt);
@@ -1451,14 +1451,16 @@ vect_do_peeling_for_loop_bound (loop_vec_info loop_vinfo, tree *ratio,
 
    Set the number of iterations for the loop represented by LOOP_VINFO
    to the minimum between LOOP_NITERS (the original iteration count of the loop)
-   and the misalignment of DR - the first data reference recorded in
+   and the misalignment of DR - the data reference recorded in
    LOOP_VINFO_UNALIGNED_DR (LOOP_VINFO).  As a result, after the execution of 
    this loop, the data reference DR will refer to an aligned location.
 
    The following computation is generated:
 
-   compute address misalignment in bytes:
-   addr_mis = addr & (vectype_size - 1)
+   If the misalignment of DR is known at compile time:
+     addr_mis = int mis = DR_MISALIGNMENT (dr);
+   Else, compute address misalignment in bytes:
+     addr_mis = addr & (vectype_size - 1)
 
    prolog_niters = min ( LOOP_NITERS , (VF - addr_mis/elem_size)&(VF-1) )
    
@@ -1479,37 +1481,53 @@ vect_gen_niters_for_prolog_loop (loop_vec_info loop_vinfo, tree loop_niters)
   stmt_vec_info stmt_info = vinfo_for_stmt (dr_stmt);
   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
   int vectype_align = TYPE_ALIGN (vectype) / BITS_PER_UNIT;
-  tree elem_misalign;
-  tree byte_misalign;
-  tree new_stmts = NULL_TREE;
-  tree start_addr = 
-	vect_create_addr_base_for_vector_ref (dr_stmt, &new_stmts, NULL_TREE);
-  tree ptr_type = TREE_TYPE (start_addr);
-  tree size = TYPE_SIZE (ptr_type);
-  tree type = lang_hooks.types.type_for_size (tree_low_cst (size, 1), 1);
-  tree vectype_size_minus_1 = build_int_cst (type, vectype_align - 1);
   tree vf_minus_1 = build_int_cst (unsigned_type_node, vf - 1);
   tree niters_type = TREE_TYPE (loop_niters);
-  tree elem_size_log = 
-	build_int_cst (unsigned_type_node, exact_log2 (vectype_align/vf));
-  tree vf_tree = build_int_cst (unsigned_type_node, vf);
 
   pe = loop_preheader_edge (loop); 
-  new_bb = bsi_insert_on_edge_immediate (pe, new_stmts); 
-  gcc_assert (!new_bb);
 
-  /* Create:  byte_misalign = addr & (vectype_size - 1)  */
-  byte_misalign = build2 (BIT_AND_EXPR, type, start_addr, vectype_size_minus_1);
+  if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) > 0)
+    {
+      int byte_misalign = LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo);
+      int element_size = vectype_align/vf;
+      int elem_misalign = byte_misalign / element_size;
 
-  /* Create:  elem_misalign = byte_misalign / element_size  */
-  elem_misalign = 
-	build2 (RSHIFT_EXPR, unsigned_type_node, byte_misalign, elem_size_log);
+      if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
+        fprintf (vect_dump, "known alignment = %d.", byte_misalign);
+      iters = build_int_cst (niters_type, (vf - elem_misalign)&(vf-1));
+    }
+  else
+    {
+      tree new_stmts = NULL_TREE;
+      tree start_addr =
+        vect_create_addr_base_for_vector_ref (dr_stmt, &new_stmts, NULL_TREE);
+      tree ptr_type = TREE_TYPE (start_addr);
+      tree size = TYPE_SIZE (ptr_type);
+      tree type = lang_hooks.types.type_for_size (tree_low_cst (size, 1), 1);
+      tree vectype_size_minus_1 = build_int_cst (type, vectype_align - 1);
+      tree elem_size_log =
+        build_int_cst (unsigned_type_node, exact_log2 (vectype_align/vf));
+      tree vf_tree = build_int_cst (unsigned_type_node, vf);
+      tree byte_misalign;
+      tree elem_misalign;
+
+      new_bb = bsi_insert_on_edge_immediate (pe, new_stmts);
+      gcc_assert (!new_bb);
   
-  /* Create:  (niters_type) (VF - elem_misalign)&(VF - 1)  */
-  iters = build2 (MINUS_EXPR, unsigned_type_node, vf_tree, elem_misalign);
-  iters = build2 (BIT_AND_EXPR, unsigned_type_node, iters, vf_minus_1);
-  iters = fold_convert (niters_type, iters);
+      /* Create:  byte_misalign = addr & (vectype_size - 1)  */
+      byte_misalign = 
+        build2 (BIT_AND_EXPR, type, start_addr, vectype_size_minus_1);
   
+      /* Create:  elem_misalign = byte_misalign / element_size  */
+      elem_misalign =
+        build2 (RSHIFT_EXPR, unsigned_type_node, byte_misalign, elem_size_log);
+
+      /* Create:  (niters_type) (VF - elem_misalign)&(VF - 1)  */
+      iters = build2 (MINUS_EXPR, unsigned_type_node, vf_tree, elem_misalign);
+      iters = build2 (BIT_AND_EXPR, unsigned_type_node, iters, vf_minus_1);
+      iters = fold_convert (niters_type, iters);
+    }
+
   /* Create:  prolog_loop_niters = min (iters, loop_niters) */
   /* If the loop bound is known at compile time we already verified that it is
      greater than vf; since the misalignment ('iters') is at most vf, there's
@@ -1517,12 +1535,17 @@ vect_gen_niters_for_prolog_loop (loop_vec_info loop_vinfo, tree loop_niters)
   if (TREE_CODE (loop_niters) != INTEGER_CST)
     iters = build2 (MIN_EXPR, niters_type, iters, loop_niters);
 
+  if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
+    {
+      fprintf (vect_dump, "niters for prolog loop: ");
+      print_generic_expr (vect_dump, iters, TDF_SLIM);
+    }
+
   var = create_tmp_var (niters_type, "prolog_loop_niters");
   add_referenced_tmp_var (var);
   iters_name = force_gimple_operand (iters, &stmt, false, var);
 
   /* Insert stmt on loop preheader edge.  */
-  pe = loop_preheader_edge (loop);
   if (stmt)
     {
       basic_block new_bb = bsi_insert_on_edge_immediate (pe, stmt);
@@ -1533,7 +1556,7 @@ vect_gen_niters_for_prolog_loop (loop_vec_info loop_vinfo, tree loop_niters)
 }
 
 
-/* Function vect_update_inits_of_dr
+/* Function vect_update_init_of_dr
 
    NITERS iterations were peeled from LOOP.  DR represents a data reference
    in LOOP.  This function updates the information recorded in DR to
@@ -1541,7 +1564,7 @@ vect_gen_niters_for_prolog_loop (loop_vec_info loop_vinfo, tree loop_niters)
    executed.  Specifically, it updates the OFFSET field of stmt_info.  */
 
 static void
-vect_update_inits_of_dr (struct data_reference *dr, tree niters)
+vect_update_init_of_dr (struct data_reference *dr, tree niters)
 {
   stmt_vec_info stmt_info = vinfo_for_stmt (DR_STMT (dr));
   tree offset = STMT_VINFO_VECT_INIT_OFFSET (stmt_info);
@@ -1574,13 +1597,13 @@ vect_update_inits_of_drs (loop_vec_info loop_vinfo, tree niters)
   for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
     {
       struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
-      vect_update_inits_of_dr (dr, niters);
+      vect_update_init_of_dr (dr, niters);
     }
 
   for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_datarefs); i++)
     {
       struct data_reference *dr = VARRAY_GENERIC_PTR (loop_read_datarefs, i);
-      vect_update_inits_of_dr (dr, niters);
+      vect_update_init_of_dr (dr, niters);
     }
 }
 
@@ -1618,8 +1641,8 @@ vect_do_peeling_for_alignment (loop_vec_info loop_vinfo, struct loops *loops)
 
   /* Update number of times loop executes.  */
   n_iters = LOOP_VINFO_NITERS (loop_vinfo);
-  LOOP_VINFO_NITERS (loop_vinfo) =
-    build2 (MINUS_EXPR, TREE_TYPE (n_iters), n_iters, niters_of_prolog_loop);
+  LOOP_VINFO_NITERS (loop_vinfo) = fold (build2 (MINUS_EXPR,
+		TREE_TYPE (n_iters), n_iters, niters_of_prolog_loop));
 
   /* Update the init conditions of the access functions of all data refs.  */
   vect_update_inits_of_drs (loop_vinfo, niters_of_prolog_loop);
@@ -1656,7 +1679,7 @@ vect_transform_loop (loop_vec_info loop_vinfo,
   /* Peel the loop if there are data refs with unknown alignment.
      Only one data ref with unknown store is allowed.  */
 
-  if (LOOP_DO_PEELING_FOR_ALIGNMENT (loop_vinfo))
+  if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo))
     vect_do_peeling_for_alignment (loop_vinfo, loops);
   
   /* If the loop has a symbolic number of iterations 'n' (i.e. it's not a

gcc/tree-vectorizer.c

@@ -963,7 +963,7 @@ slpeel_tree_peel_loop_to_edge (struct loop *loop, struct loops *loops,
   add_bb_to_loop (bb_before_second_loop, first_loop->outer);
 
   pre_condition =
-        build2 (LE_EXPR, boolean_type_node, first_niters, integer_zero_node);
+    fold (build2 (LE_EXPR, boolean_type_node, first_niters, integer_zero_node));
   skip_e = slpeel_add_loop_guard (bb_before_first_loop, pre_condition,
                                   bb_before_second_loop, bb_before_first_loop);
   slpeel_update_phi_nodes_for_guard (skip_e, first_loop, true /* entry-phis */,
@@ -1001,7 +1001,8 @@ slpeel_tree_peel_loop_to_edge (struct loop *loop, struct loops *loops,
   bb_after_second_loop = split_edge (second_loop->single_exit);
   add_bb_to_loop (bb_after_second_loop, second_loop->outer);
 
-  pre_condition = build2 (EQ_EXPR, boolean_type_node, first_niters, niters);
+  pre_condition = 
+	fold (build2 (EQ_EXPR, boolean_type_node, first_niters, niters));
   skip_e = slpeel_add_loop_guard (bb_between_loops, pre_condition,
                                   bb_after_second_loop, bb_before_first_loop);
   slpeel_update_phi_nodes_for_guard (skip_e, second_loop, false /* exit-phis */,
@@ -1213,7 +1214,7 @@ new_loop_vec_info (struct loop *loop)
   LOOP_VINFO_EXIT_COND (res) = NULL;
   LOOP_VINFO_NITERS (res) = NULL;
   LOOP_VINFO_VECTORIZABLE_P (res) = 0;
-  LOOP_DO_PEELING_FOR_ALIGNMENT (res) = false;
+  LOOP_PEELING_FOR_ALIGNMENT (res) = 0;
   LOOP_VINFO_VECT_FACTOR (res) = 0;
   VARRAY_GENERIC_PTR_INIT (LOOP_VINFO_DATAREF_WRITES (res), 20,
 			   "loop_write_datarefs");

gcc/tree-vectorizer.h

@@ -95,9 +95,15 @@ typedef struct _loop_vec_info {
   /* Unknown DRs according to which loop was peeled.  */
   struct data_reference *unaligned_dr;
 
-  /* If true, loop is peeled.
-   unaligned_drs show in this case DRs used for peeling.  */
-  bool do_peeling_for_alignment;
+  /* peeling_for_alignment indicates whether peeling for alignment will take
+     place, and what the peeling factor should be:
+     peeling_for_alignment = X means:
+        If X=0: Peeling for alignment will not be applied.
+        If X>0: Peel first X iterations.
+        If X=-1: Generate a runtime test to calculate the number of iterations
+                 to be peeled, using the dataref recorded in the field
+                 unaligned_dr.  */
+  int peeling_for_alignment;
 
   /* All data references in the loop that are being written to.  */
   varray_type data_ref_writes;
@@ -119,7 +125,7 @@ typedef struct _loop_vec_info {
 #define LOOP_VINFO_DATAREF_WRITES(L) (L)->data_ref_writes
 #define LOOP_VINFO_DATAREF_READS(L)  (L)->data_ref_reads
 #define LOOP_VINFO_INT_NITERS(L) (TREE_INT_CST_LOW ((L)->num_iters))
-#define LOOP_DO_PEELING_FOR_ALIGNMENT(L) (L)->do_peeling_for_alignment
+#define LOOP_PEELING_FOR_ALIGNMENT(L) (L)->peeling_for_alignment
 #define LOOP_VINFO_UNALIGNED_DR(L) (L)->unaligned_dr
 #define LOOP_VINFO_LOC(L)          (L)->loop_line_number
 
@@ -242,7 +248,8 @@ vinfo_for_stmt (tree stmt)
 /* Info on data references alignment.                              */
 /*-----------------------------------------------------------------*/
 
-/* The misalignment of the memory access in bytes.  */
+/* Reflects actual alignment of first access in the vectorized loop,
+   taking into account peeling/versioning if applied.  */
 #define DR_MISALIGNMENT(DR)   (DR)->aux
 
 static inline bool
@@ -252,9 +259,9 @@ aligned_access_p (struct data_reference *data_ref_info)
 }
 
 static inline bool
-unknown_alignment_for_access_p (struct data_reference *data_ref_info)
+known_alignment_for_access_p (struct data_reference *data_ref_info)
 {
-  return (DR_MISALIGNMENT (data_ref_info) == -1);
+  return (DR_MISALIGNMENT (data_ref_info) != -1);
 }
 
 /* Perform signed modulo, always returning a non-negative value.  */