Remove STMT_VINFO_VEC_STMTS

The following removes the last uses of STMT_VINFO_VEC_STMTS and
the vector itself.  Vector stmts are recorded in SLP nodes now.

The last use is a bit strange - it was introduced by
Richard S. in r8-6064-ga57776a1136962 and affects only
power7 and below (the re-align optimized load path).  The
check should have never been true since vect_vfa_access_size
is only ever invoked before stmt transform.  I have done
the "conservative" change of making it always true now
(so the code is now entered).  I can as well remove it, but
I wonder if you remember anything about this ...

	* tree-vectorizer.h (_stmt_vec_info::vec_stmts): Remove.
	(STMT_VINFO_VEC_STMTS): Likewise.
	* tree-vectorizer.cc (vec_info::new_stmt_vec_info): Do not
	initialize it.
	(vec_info::free_stmt_vec_info): Nor free it.
	* tree-vect-data-refs.cc (vect_vfa_access_size): Remove
	check on STMT_VINFO_VEC_STMTS.

Author: rguenth

gcc/tree-vect-data-refs.cc

@@ -3956,8 +3956,7 @@ vect_vfa_access_size (vec_info *vinfo, dr_vec_info *dr_info)
     }
   tree vectype = STMT_VINFO_VECTYPE (stmt_vinfo);
   int misalignment;
-  if (STMT_VINFO_VEC_STMTS (stmt_vinfo).exists ()
-      && ((misalignment = dr_misalignment (dr_info, vectype)), true)
+  if (((misalignment = dr_misalignment (dr_info, vectype)), true)
       && (vect_supportable_dr_alignment (vinfo, dr_info, vectype, misalignment)
 	  == dr_explicit_realign_optimized))
     {

gcc/tree-vectorizer.cc

@@ -724,7 +724,6 @@ vec_info::new_stmt_vec_info (gimple *stmt)
   STMT_VINFO_REDUC_IDX (res) = -1;
   STMT_VINFO_SLP_VECT_ONLY (res) = false;
   STMT_VINFO_SLP_VECT_ONLY_PATTERN (res) = false;
-  STMT_VINFO_VEC_STMTS (res) = vNULL;
   res->reduc_initial_values = vNULL;
   res->reduc_scalar_results = vNULL;
 
@@ -790,7 +789,6 @@ vec_info::free_stmt_vec_info (stmt_vec_info stmt_info)
 
   stmt_info->reduc_initial_values.release ();
   stmt_info->reduc_scalar_results.release ();
-  STMT_VINFO_VEC_STMTS (stmt_info).release ();
   free (stmt_info);
 }
 

gcc/tree-vectorizer.h

@@ -1354,9 +1354,6 @@ class _stmt_vec_info {
   /* The vector type to be used for the LHS of this statement.  */
   tree vectype;
 
-  /* The vectorized stmts.  */
-  vec<gimple *> vec_stmts;
-
   /* The following is relevant only for stmts that contain a non-scalar
      data-ref (array/pointer/struct access). A GIMPLE stmt is expected to have
      at most one such data-ref.  */
@@ -1577,7 +1574,6 @@ struct gather_scatter_info {
 #define STMT_VINFO_RELEVANT(S)             (S)->relevant
 #define STMT_VINFO_LIVE_P(S)               (S)->live
 #define STMT_VINFO_VECTYPE(S)              (S)->vectype
-#define STMT_VINFO_VEC_STMTS(S)            (S)->vec_stmts
 #define STMT_VINFO_VECTORIZABLE(S)         (S)->vectorizable
 #define STMT_VINFO_DATA_REF(S)             ((S)->dr_aux.dr + 0)
 #define STMT_VINFO_GATHER_SCATTER_P(S)	   (S)->gather_scatter_p