re PR tree-optimization/15991 (phi nodes with identical arguments still remain at t50.tailc)

	PR tree-optimization/15991
	* tree-cfg.c (tree_block_label): Export.
	* tree-flow-inline.h (bsi_after_labels): New function.
	* tree-flow.h (bsi_after_labels, tree_block_label): Declare.
	* tree-ssa.c (propagate_into_addr): New function.
	(replace_immediate_uses): Handle propagation of pointer constants.
	(raise_value): Do not restrict propagation of pointer constants.
	* tree-ssanames.c (duplicate_ssa_name): New function.
	* tree.h (duplicate_ssa_name): Declare.

From-SVN: r83297

1 files changed, 25 insertions, 0 deletions

diff --git a/gcc/tree-ssanames.c b/gcc/tree-ssanames.c
index 6a0fda6..d498270 100644
--- a/gcc/tree-ssanames.c
+++ b/gcc/tree-ssanames.c
@@ -191,4 +191,29 @@ release_ssa_name (tree var)
     }
 }
 
+/* Creates a duplicate of a ssa name NAME defined in statement STMT.  */
+
+tree
+duplicate_ssa_name (tree name, tree stmt)
+{
+  tree new_name = make_ssa_name (SSA_NAME_VAR (name), stmt);
+  struct ptr_info_def *old_ptr_info = SSA_NAME_PTR_INFO (name);
+  struct ptr_info_def *new_ptr_info;
+
+  if (!old_ptr_info)
+    return new_name;
+
+  new_ptr_info = ggc_alloc (sizeof (struct ptr_info_def));
+  *new_ptr_info = *old_ptr_info;
+
+  if (old_ptr_info->pt_vars)
+    {
+      new_ptr_info->pt_vars = BITMAP_GGC_ALLOC ();
+      bitmap_copy (new_ptr_info->pt_vars, old_ptr_info->pt_vars);
+    }
+
+  SSA_NAME_PTR_INFO (new_name) = new_ptr_info;
+  return new_name;
+}
+
 #include "gt-tree-ssanames.h"