2014-07-08 Richard Biener <rguenther@suse.de>

	* tree-ssa-dom.h (loop_depth_of_name): Remove.
	* tree-ssa-dom.c (record_equivalences_from_phis): Remove
	restriction on loop depth difference.
	(record_equality): Likewise.
	(propagate_rhs_into_lhs): Likewise.  Simplify condition.
	(loop_depth_of_name): Remove.
	* tree-ssa-copy.c (copy_prop_visit_phi_node): Remove
	restriction on loop depth difference.
	(init_copy_prop): Likewise.

	* gcc.dg/tree-ssa/ssa-pre-16.c: Adjust expected eliminations.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@212352 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 4 insertions, 42 deletions

diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index 795ed09ae86..d0501a2d23d 100644
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -1235,12 +1235,7 @@ record_equivalences_from_phis (basic_block bb)
 	 inferred from a comparison.  All uses of this ssa name are dominated
 	 by this assignment, so unwinding just costs time and space.  */
       if (i == gimple_phi_num_args (phi)
-	  && may_propagate_copy (lhs, rhs)
-	  /* Do not propagate copies if the propagated value is at a deeper loop
-	     depth than the propagatee.  Otherwise, this may introduce uses
-	     of loop variant variables outside of their loops and prevent
-	     coalescing opportunities.  */
-	  && !(loop_depth_of_name (rhs) > loop_depth_of_name (lhs)))
+	  && may_propagate_copy (lhs, rhs))
 	set_ssa_name_value (lhs, rhs);
     }
 }
@@ -1575,33 +1570,6 @@ record_const_or_copy_1 (tree x, tree y, tree prev_x)
   const_and_copies_stack.quick_push (x);
 }
 
-/* Return the loop depth of the basic block of the defining statement of X.
-   This number should not be treated as absolutely correct because the loop
-   information may not be completely up-to-date when dom runs.  However, it
-   will be relatively correct, and as more passes are taught to keep loop info
-   up to date, the result will become more and more accurate.  */
-
-int
-loop_depth_of_name (tree x)
-{
-  gimple defstmt;
-  basic_block defbb;
-
-  /* If it's not an SSA_NAME, we have no clue where the definition is.  */
-  if (TREE_CODE (x) != SSA_NAME)
-    return 0;
-
-  /* Otherwise return the loop depth of the defining statement's bb.
-     Note that there may not actually be a bb for this statement, if the
-     ssa_name is live on entry.  */
-  defstmt = SSA_NAME_DEF_STMT (x);
-  defbb = gimple_bb (defstmt);
-  if (!defbb)
-    return 0;
-
-  return bb_loop_depth (defbb);
-}
-
 /* Record that X is equal to Y in const_and_copies.  Record undo
    information in the block-local vector.  */
 
@@ -1641,8 +1609,7 @@ record_equality (tree x, tree y)
      long as we canonicalize on one value.  */
   if (is_gimple_min_invariant (y))
     ;
-  else if (is_gimple_min_invariant (x)
-	   || (loop_depth_of_name (x) <= loop_depth_of_name (y)))
+  else if (is_gimple_min_invariant (x))
     prev_x = x, x = y, y = prev_x, prev_x = prev_y;
   else if (prev_x && is_gimple_min_invariant (prev_x))
     x = y, y = prev_x, prev_x = prev_y;
@@ -2686,13 +2653,8 @@ get_lhs_or_phi_result (gimple stmt)
 static void
 propagate_rhs_into_lhs (gimple stmt, tree lhs, tree rhs, bitmap interesting_names)
 {
-  /* First verify that propagation is valid and isn't going to move a
-     loop variant variable outside its loop.  */
-  if (! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs)
-      && (TREE_CODE (rhs) != SSA_NAME
-	  || ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs))
-      && may_propagate_copy (lhs, rhs)
-      && loop_depth_of_name (lhs) >= loop_depth_of_name (rhs))
+  /* First verify that propagation is valid.  */
+  if (may_propagate_copy (lhs, rhs))
     {
       use_operand_p use_p;
       imm_use_iterator iter;