re PR tree-optimization/88945 (ICE in fold_convert_loc in FRE when using -fdump-tree-fre-details)

2019-03-18  Richard Biener  <rguenther@suse.de>

	PR middle-end/88945
	* tree-ssanames.c (release_ssa_name_fn): For released SSA names
	use a TREE_TYPE of error_mark_node to avoid ICEs when dumping
	basic-blocks that are removed.  Remove restoring SSA_NAME_VAR.
	* tree-outof-ssa.c (eliminate_useless_phis): Remove redundant checking.

From-SVN: r269765

gcc/ChangeLog

+2019-03-18  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/88945
+	* tree-ssanames.c (release_ssa_name_fn): For released SSA names
+	use a TREE_TYPE of error_mark_node to avoid ICEs when dumping
+	basic-blocks that are removed.  Remove restoring SSA_NAME_VAR.
+	* tree-outof-ssa.c (eliminate_useless_phis): Remove redundant checking.
+
 2019-03-18  Andrew Stubbs  <ams@codesourcery.com>
 
 	* config/gcn/gcn-run.c (struct output): Make next_output unsigned.

gcc/tree-outof-ssa.c

@@ -809,26 +809,7 @@ eliminate_useless_phis (void)
 	  gphi *phi = gsi.phi ();
 	  result = gimple_phi_result (phi);
 	  if (virtual_operand_p (result))
-	    {
-	      /* There should be no arguments which are not virtual, or the
-	         results will be incorrect.  */
-	      if (flag_checking)
-		for (size_t i = 0; i < gimple_phi_num_args (phi); i++)
-		  {
-		    tree arg = PHI_ARG_DEF (phi, i);
-		    if (TREE_CODE (arg) == SSA_NAME
-			&& !virtual_operand_p (arg))
-		      {
-			fprintf (stderr, "Argument of PHI is not virtual (");
-			print_generic_expr (stderr, arg, TDF_SLIM);
-			fprintf (stderr, "), but the result is :");
-			print_gimple_stmt (stderr, phi, 0, TDF_SLIM);
-			internal_error ("SSA corruption");
-		      }
-		  }
-
-	      remove_phi_node (&gsi, true);
-	    }
+	    remove_phi_node (&gsi, true);
           else
 	    {
 	      /* Also remove real PHIs with no uses.  */

gcc/tree-ssanames.c

@@ -595,7 +595,6 @@ release_ssa_name_fn (struct function *fn, tree var)
      defining statement.  */
   if (! SSA_NAME_IN_FREE_LIST (var))
     {
-      tree saved_ssa_name_var = SSA_NAME_VAR (var);
       int saved_ssa_name_version = SSA_NAME_VERSION (var);
       use_operand_p imm = &(SSA_NAME_IMM_USE_NODE (var));
 
@@ -621,13 +620,14 @@ release_ssa_name_fn (struct function *fn, tree var)
       /* Restore the version number.  */
       SSA_NAME_VERSION (var) = saved_ssa_name_version;
 
-      /* Hopefully this can go away once we have the new incremental
-         SSA updating code installed.  */
-      SET_SSA_NAME_VAR_OR_IDENTIFIER (var, saved_ssa_name_var);
-
       /* Note this SSA_NAME is now in the first list.  */
       SSA_NAME_IN_FREE_LIST (var) = 1;
 
+      /* Put in a non-NULL TREE_TYPE so dumping code will not ICE
+         if it happens to come along a released SSA name and tries
+	 to inspect its type.  */
+      TREE_TYPE (var) = error_mark_node;
+
       /* And finally queue it so that it will be put on the free list.  */
       vec_safe_push (FREE_SSANAMES_QUEUE (fn), var);
     }