[PATCH GCC]Preserve ssa name (thus vrp info) for IV structure. Committed.

[Bin.Cheng]

Hi,
I applied this obvious patch to trunk.  It was approved in last Stage 4.

Thanks,
bin

2015-06-03  Bin Cheng  <bin.cheng@arm.com>

    * tree-ssa-loop-ivopts.c (dump_iv): New parameter.
    (dump_use, dump_cand, find_induction_variables): Pass new argument
    to dump_iv.
    (record_use): Preserve the ssa name information in IV.
-------------- next part --------------
Index: gcc/tree-ssa-loop-ivopts.c
===================================================================
--- gcc/tree-ssa-loop-ivopts.c	(revision 224056)
+++ gcc/tree-ssa-loop-ivopts.c	(working copy)
@@ -517,9 +517,9 @@ single_dom_exit (struct loop *loop)
 /* Dumps information about the induction variable IV to FILE.  */
 
 void
-dump_iv (FILE *file, struct iv *iv)
+dump_iv (FILE *file, struct iv *iv, bool dump_name)
 {
-  if (iv->ssa_name)
+  if (iv->ssa_name && dump_name)
     {
       fprintf (file, "ssa name ");
       print_generic_expr (file, iv->ssa_name, TDF_SLIM);
@@ -596,7 +596,7 @@ dump_use (FILE *file, struct iv_use *use)
     print_generic_expr (file, *use->op_p, TDF_SLIM);
   fprintf (file, "\n");
 
-  dump_iv (file, use->iv);
+  dump_iv (file, use->iv, false);
 
   if (use->related_cands)
     {
@@ -684,7 +684,7 @@ dump_cand (FILE *file, struct iv_cand *cand)
       break;
     }
 
-  dump_iv (file, iv);
+  dump_iv (file, iv, false);
 }
 
 /* Returns the info for ssa version VER.  */
@@ -1326,7 +1326,7 @@ find_induction_variables (struct ivopts_data *data
       EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi)
 	{
 	  if (ver_info (data, i)->iv)
-	    dump_iv (dump_file, ver_info (data, i)->iv);
+	    dump_iv (dump_file, ver_info (data, i)->iv, true);
 	}
     }
 
@@ -1356,10 +1356,6 @@ record_use (struct ivopts_data *data, tree *use_p,
   use->addr_base = addr_base;
   use->addr_offset = addr_offset;
 
-  /* To avoid showing ssa name in the dumps, if it was not reset by the
-     caller.  */
-  iv->ssa_name = NULL_TREE;
-
   data->iv_uses.safe_push (use);
 
   return use;