From c72321c9a7c869ae5cb7f5bbec1ea4e8c8d3c50a Mon Sep 17 00:00:00 2001
From: Jan Hubicka <jh@suse.cz>
Date: Sun, 20 Jul 2008 18:06:51 +0200
Subject: cgraph.c (cgraph_add_new_function): Do early local passes.

	* cgraph.c (cgraph_add_new_function): Do early local passes.
	* tree-nrv.c (gate_pass_return_slot): New gate.
	(pass_nrv): Add the gate.
	* tree-ssa-coalese.c (hash_ssa_name_by_var, eq_ssa_name_by_var): New
	functions.
	(coalesce_ssa_name): Coalesce SSA names.
	* tree-ssa-live.c (remove_unused_locals): Be more conservative when
	not optimizing so unused user vars remains visible.
	* common.opt (flag_tree_ter): Always enable by default.
	* tree-ssa-ter.c: Include flags.h
	(is_replaceable_p): Check that locations match; when aliasing is missing
	be conservative about loads.
	* tree-optimize.c (gate_init_datastructures): Remove.
	(pass_init_datastructures): New.
	* passes.c: Reorder passes so we always go into SSA.

From-SVN: r138010
---
 gcc/tree-ssa-coalesce.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

(limited to 'gcc/tree-ssa-coalesce.c')

diff --git a/gcc/tree-ssa-coalesce.c b/gcc/tree-ssa-coalesce.c
index 388437d44bb..a96029aa7c5 100644
--- a/gcc/tree-ssa-coalesce.c
+++ b/gcc/tree-ssa-coalesce.c
@@ -1297,6 +1297,24 @@ coalesce_partitions (var_map map, ssa_conflicts_p graph, coalesce_list_p cl,
     }
 }
 
+/* Returns a hash code for P.  */
+
+static hashval_t
+hash_ssa_name_by_var (const void *p)
+{
+  const_tree n = (const_tree) p;
+  return (hashval_t) htab_hash_pointer (SSA_NAME_VAR (n));
+}
+
+/* Returns nonzero if P1 and P2 are equal.  */
+
+static int
+eq_ssa_name_by_var (const void *p1, const void *p2)
+{
+  const_tree n1 = (const_tree) p1;
+  const_tree n2 = (const_tree) p2;
+  return SSA_NAME_VAR (n1) == SSA_NAME_VAR (n2);
+}
 
 /* Reduce the number of copies by coalescing variables in the function.  Return
    a partition map with the resulting coalesces.  */
@@ -1310,10 +1328,42 @@ coalesce_ssa_name (void)
   coalesce_list_p cl;
   bitmap used_in_copies = BITMAP_ALLOC (NULL);
   var_map map;
+  unsigned int i;
+  static htab_t ssa_name_hash;
 
   cl = create_coalesce_list ();
   map = create_outofssa_var_map (cl, used_in_copies);
 
+  /* We need to coalesce all names originating same SSA_NAME_VAR
+     so debug info remains undisturbed.  */
+  if (!optimize)
+    {
+      ssa_name_hash = htab_create (10, hash_ssa_name_by_var,
+      				   eq_ssa_name_by_var, NULL);
+      for (i = 1; i < num_ssa_names; i++)
+	{
+	  tree a = ssa_name (i);
+
+	  if (a && SSA_NAME_VAR (a) && !DECL_ARTIFICIAL (SSA_NAME_VAR (a)))
+	    {
+	      tree *slot = (tree *) htab_find_slot (ssa_name_hash, a, INSERT);
+
+	      if (!*slot)
+		*slot = a;
+	      else
+		{
+		  add_coalesce (cl, SSA_NAME_VERSION (a), SSA_NAME_VERSION (*slot),
+				MUST_COALESCE_COST - 1);
+		  bitmap_set_bit (used_in_copies, SSA_NAME_VERSION (a));
+		  bitmap_set_bit (used_in_copies, SSA_NAME_VERSION (*slot));
+		}
+	    }
+	}
+      htab_delete (ssa_name_hash);
+    }
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    dump_var_map (dump_file, map);
+
   /* Don't calculate live ranges for variables not in the coalesce list.  */
   partition_view_bitmap (map, used_in_copies, true);
   BITMAP_FREE (used_in_copies);
-- 
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