re PR tree-optimization/84178 (ICE in release_bb_predicate)

2018-03-08  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/84178
	* tree-if-conv.c (combine_blocks): Move insert_gimplified_predicates
	to caller.
	(version_loop_for_if_conversion): Delay update_ssa call.
	(tree_if_conversion): Delay update_ssa until after predicate
	insertion.

	* gcc.dg/torture/pr84178-2.c: New testcase.

From-SVN: r258364

gcc/ChangeLog

+2018-03-08  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/84178
+	* tree-if-conv.c (combine_blocks): Move insert_gimplified_predicates
+	to caller.
+	(version_loop_for_if_conversion): Delay update_ssa call.
+	(tree_if_conversion): Delay update_ssa until after predicate
+	insertion.
+
 2018-03-08  David Malcolm  <dmalcolm@redhat.com>
 
 	PR tree-optimization/84178

gcc/testsuite/ChangeLog

+2018-03-08  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/84178
+	* gcc.dg/torture/pr84178-2.c: New testcase.
+
 2018-03-08  David Malcolm  <dmalcolm@redhat.com>
 
 	PR tree-optimization/84178

gcc/testsuite/gcc.dg/torture/pr84178-2.c

+/* { dg-do compile } */
+/* { dg-additional-options "-fno-tree-forwprop" } */
+
+int zy, h4;
+
+void
+r8 (long int mu, int *jr, int *fi, short int dv)
+{
+  do
+    {
+      int tx;
+
+      tx = !!h4 ? (zy + h4) : 1;
+      mu = tx;
+      *jr = (((unsigned char) mu > (254 >> dv)) ? 0 : (unsigned char) tx) + *fi;
+    } while (*jr == 0);
+
+  r8 (mu, jr, fi, 1);
+}
+

gcc/tree-if-conv.c

@@ -2371,7 +2371,6 @@ combine_blocks (struct loop *loop)
   edge_iterator ei;
 
   remove_conditions_and_labels (loop);
-  insert_gimplified_predicates (loop);
   predicate_all_scalar_phis (loop);
 
   if (any_pred_load_store)
@@ -2593,7 +2592,6 @@ version_loop_for_if_conversion (struct loop *loop)
   gsi = gsi_last_bb (cond_bb);
   gimple_call_set_arg (g, 1, build_int_cst (integer_type_node, new_loop->num));
   gsi_insert_before (&gsi, g, GSI_SAME_STMT);
-  update_ssa (TODO_update_ssa);
   return new_loop;
 }
 
@@ -2811,6 +2809,7 @@ tree_if_conversion (struct loop *loop)
   unsigned int todo = 0;
   bool aggressive_if_conv;
   struct loop *rloop;
+  bool need_update_ssa = false;
 
  again:
   rloop = NULL;
@@ -2856,6 +2855,7 @@ tree_if_conversion (struct loop *loop)
       struct loop *nloop = version_loop_for_if_conversion (vloop);
       if (nloop == NULL)
 	goto cleanup;
+      need_update_ssa = true;
       if (vloop != loop)
 	{
 	  /* If versionable_outer_loop_p decided to version the
@@ -2880,6 +2880,13 @@ tree_if_conversion (struct loop *loop)
 	}
     }
 
+  /* Due to hard to fix issues we end up with immediate uses recorded
+     for not yet inserted predicates which will confuse SSA update so
+     we delayed this from after versioning to after predicate insertion.  */
+  insert_gimplified_predicates (loop);
+  if (need_update_ssa)
+    update_ssa (TODO_update_ssa);
+
   /* Now all statements are if-convertible.  Combine all the basic
      blocks into one huge basic block doing the if-conversion
      on-the-fly.  */