--- a/gcc/tree-into-ssa.c	Thu Oct 25 07:37:49 2018 +0900
+++ b/gcc/tree-into-ssa.c	Thu Feb 13 11:34:05 2020 +0900
@@ -1,5 +1,5 @@
 /* Rewrite a program in Normal form into SSA.
-   Copyright (C) 2001-2018 Free Software Foundation, Inc.
+   Copyright (C) 2001-2020 Free Software Foundation, Inc.
    Contributed by Diego Novillo <dnovillo@redhat.com>
 
 This file is part of GCC.
@@ -940,14 +940,18 @@
   if (!blocks_with_phis_to_rewrite)
     return;
 
-  bitmap_set_bit (blocks_with_phis_to_rewrite, idx);
-
-  n = (unsigned) last_basic_block_for_fn (cfun) + 1;
-  if (phis_to_rewrite.length () < n)
-    phis_to_rewrite.safe_grow_cleared (n);
-
-  phis = phis_to_rewrite[idx];
-  phis.reserve (10);
+  if (bitmap_set_bit (blocks_with_phis_to_rewrite, idx))
+    {
+      n = (unsigned) last_basic_block_for_fn (cfun) + 1;
+      if (phis_to_rewrite.length () < n)
+	phis_to_rewrite.safe_grow_cleared (n);
+
+      phis = phis_to_rewrite[idx];
+      gcc_assert (!phis.exists ());
+      phis.create (10);
+    }
+  else
+    phis = phis_to_rewrite[idx];
 
   phis.safe_push (phi);
   phis_to_rewrite[idx] = phis;
@@ -1436,20 +1440,12 @@
       for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi);
 	   gsi_next (&gsi))
 	{
-	  tree currdef, res, argvar;
+	  tree currdef, res;
 	  location_t loc;
 
 	  phi = gsi.phi ();
 	  res = gimple_phi_result (phi);
-	  /* If we have pre-existing PHI (via the GIMPLE FE) its args may
-	     be different vars than existing vars and they may be constants
-	     as well.  Note the following supports partial SSA for PHI args.  */
-	  argvar = gimple_phi_arg_def (phi, e->dest_idx);
-	  if (argvar && ! DECL_P (argvar))
-	    continue;
-	  if (!argvar)
-	    argvar = SSA_NAME_VAR (res);
-	  currdef = get_reaching_def (argvar);
+	  currdef = get_reaching_def (SSA_NAME_VAR (res));
 	  /* Virtual operand PHI args do not need a location.  */
 	  if (virtual_operand_p (res))
 	    loc = UNKNOWN_LOCATION;
@@ -2119,7 +2115,7 @@
           /* Update the argument if there is a reaching def.  */
 	  if (reaching_def)
 	    {
-	      source_location locus;
+	      location_t locus;
 	      int arg_i = PHI_ARG_INDEX_FROM_USE (arg_p);
 
 	      SET_USE (arg_p, reaching_def);
@@ -2433,6 +2429,12 @@
   bitmap_head *dfs;
   basic_block bb;
 
+  /* Increase the set of variables we can rewrite into SSA form
+     by clearing TREE_ADDRESSABLE and setting DECL_GIMPLE_REG_P
+     and transform the IL to support this.  */
+  if (optimize)
+    execute_update_addresses_taken ();
+
   /* Initialize operand data structures.  */
   init_ssa_operands (fun);
 
@@ -2591,11 +2593,9 @@
     }
 }
 
-
-/* Do a dominator walk starting at BB processing statements that
-   reference symbols in SSA operands.  This is very similar to
-   mark_def_sites, but the scan handles statements whose operands may
-   already be SSA names.
+/* Processing statements in BB that reference symbols in SSA operands.
+   This is very similar to mark_def_sites, but the scan handles
+   statements whose operands may already be SSA names.
 
    If INSERT_PHI_P is true, mark those uses as live in the
    corresponding block.  This is later used by the PHI placement
@@ -2608,9 +2608,8 @@
 	   that.  */
 
 static void
-prepare_block_for_update (basic_block bb, bool insert_phi_p)
+prepare_block_for_update_1 (basic_block bb, bool insert_phi_p)
 {
-  basic_block son;
   edge e;
   edge_iterator ei;
 
@@ -2692,13 +2691,51 @@
 	}
     }
 
-  /* Now visit all the blocks dominated by BB.  */
-  for (son = first_dom_son (CDI_DOMINATORS, bb);
-       son;
-       son = next_dom_son (CDI_DOMINATORS, son))
-    prepare_block_for_update (son, insert_phi_p);
 }
 
+/* Do a dominator walk starting at BB processing statements that
+   reference symbols in SSA operands.  This is very similar to
+   mark_def_sites, but the scan handles statements whose operands may
+   already be SSA names.
+
+   If INSERT_PHI_P is true, mark those uses as live in the
+   corresponding block.  This is later used by the PHI placement
+   algorithm to make PHI pruning decisions.
+
+   FIXME.  Most of this would be unnecessary if we could associate a
+	   symbol to all the SSA names that reference it.  But that
+	   sounds like it would be expensive to maintain.  Still, it
+	   would be interesting to see if it makes better sense to do
+	   that.  */
+static void
+prepare_block_for_update (basic_block bb, bool insert_phi_p)
+{
+  size_t sp = 0;
+  basic_block *worklist;
+
+  /* Allocate the worklist.  */
+  worklist = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun));
+  /* Add the BB to the worklist.  */
+  worklist[sp++] = bb;
+
+  while (sp)
+    {
+      basic_block bb;
+      basic_block son;
+
+      /* Pick a block from the worklist.  */
+      bb = worklist[--sp];
+
+      prepare_block_for_update_1 (bb, insert_phi_p);
+
+      /* Now add all the blocks dominated by BB to the worklist.  */
+      for (son = first_dom_son (CDI_DOMINATORS, bb);
+	   son;
+	   son = next_dom_son (CDI_DOMINATORS, son))
+	worklist[sp++] = son;
+    }
+  free (worklist);
+}
 
 /* Helper for prepare_names_to_update.  Mark all the use sites for
    NAME as interesting.  BLOCKS and INSERT_PHI_P are as in
@@ -2939,11 +2976,7 @@
 
   if (blocks_with_phis_to_rewrite)
     EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi)
-      {
-	vec<gphi *> phis = phis_to_rewrite[i];
-	phis.release ();
-	phis_to_rewrite[i].create (0);
-      }
+      phis_to_rewrite[i].release ();
 
   BITMAP_FREE (blocks_with_phis_to_rewrite);
   BITMAP_FREE (blocks_to_update);
@@ -3312,7 +3345,7 @@
 
 		  if (SSA_NAME_IN_FREE_LIST (use))
 		    {
-		      error ("statement uses released SSA name:");
+		      error ("statement uses released SSA name");
 		      debug_gimple_stmt (stmt);
 		      fprintf (stderr, "The use of ");
 		      print_generic_expr (stderr, use);