* tree-ssa-dom.c (cprop_into_successor_phis): Also propagate

        edge implied equivalences into successor phis.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@202345 138bc75d-0d04-0410-961f-82ee72b054a4

2 files changed, 29 insertions, 0 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 451879429b0..67cf9e57a89 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2013-09-06  Jeff Law  <law@redhat.com>
+
+	* tree-ssa-dom.c (cprop_into_successor_phis): Also propagate
+	edge implied equivalences into successor phis.
+
 2013-09-06  Joern Rennecke  <joern.rennecke@embecosm.com>
 
 	* resource.c (mark_referenced_resources): Handle COND_EXEC.
diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index 691e6f905a2..f999a648e26 100644
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -1642,6 +1642,28 @@ cprop_into_successor_phis (basic_block bb)
       if (gsi_end_p (gsi))
 	continue;
 
+      /* We may have an equivalence associated with this edge.  While
+	 we can not propagate it into non-dominated blocks, we can
+	 propagate them into PHIs in non-dominated blocks.  */
+
+      /* Push the unwind marker so we can reset the const and copies
+	 table back to its original state after processing this edge.  */
+      const_and_copies_stack.safe_push (NULL_TREE);
+
+      /* Extract and record any simple NAME = VALUE equivalences. 
+
+	 Don't bother with [01] = COND equivalences, they're not useful
+	 here.  */
+      struct edge_info *edge_info = (struct edge_info *) e->aux;
+      if (edge_info)
+	{
+	  tree lhs = edge_info->lhs;
+	  tree rhs = edge_info->rhs;
+
+	  if (lhs && TREE_CODE (lhs) == SSA_NAME)
+	    record_const_or_copy (lhs, rhs);
+	}
+
       indx = e->dest_idx;
       for ( ; !gsi_end_p (gsi); gsi_next (&gsi))
 	{
@@ -1667,6 +1689,8 @@ cprop_into_successor_phis (basic_block bb)
 	      && may_propagate_copy (orig_val, new_val))
 	    propagate_value (orig_p, new_val);
 	}
+
+      restore_vars_to_original_value ();
     }
 }