re PR tree-optimization/58946 (internal compiler error: in operator[], at vec.h:722)

	PR tree-optimization/58946
	* tree-ssa-reassoc.c (maybe_optimize_range_tests): Update all
	bbs with bbinfo[idx].op != NULL before all blocks with
	bbinfo[idx].op == NULL.

	* gcc.c-torture/compile/pr58946.c: New test.

From-SVN: r204348

gcc/ChangeLog

+2013-11-04  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/58946
+	* tree-ssa-reassoc.c (maybe_optimize_range_tests): Update all
+	bbs with bbinfo[idx].op != NULL before all blocks with
+	bbinfo[idx].op == NULL.
+
 2013-11-04  Richard Sandiford  <rdsandiford@googlemail.com>
 
 	* config/avr/avr-log.c (avr_double_int_pop_digit): Delete.

gcc/testsuite/ChangeLog

+2013-11-04  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/58946
+	* gcc.c-torture/compile/pr58946.c: New test.
+
 2013-11-03  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/52071

gcc/testsuite/gcc.c-torture/compile/pr58946.c

+/* PR tree-optimization/58946 */
+
+int
+foo (unsigned int c)
+{
+  unsigned int d, e, f;
+  if ((int) c < 0)
+    d = 0;
+  else
+    d = c;
+  if (d == 0)
+    e = __INT_MAX__ + 1U;
+  else
+    e = d;
+  if ((int) e < 0)
+    f = 0;
+  else
+    f = e;
+  return f;
+}

gcc/tree-ssa-reassoc.c

@@ -2657,6 +2657,7 @@ maybe_optimize_range_tests (gimple stmt)
   edge e;
   vec<operand_entry_t> ops = vNULL;
   vec<inter_bb_range_test_entry> bbinfo = vNULL;
+  bool any_changes = false;
 
   /* Consider only basic blocks that end with GIMPLE_COND or
      a cast statement satisfying final_range_test_p.  All
@@ -2870,36 +2871,26 @@ maybe_optimize_range_tests (gimple stmt)
 	break;
     }
   if (ops.length () > 1)
+    any_changes = optimize_range_tests (ERROR_MARK, &ops);
+  if (any_changes)
     {
       unsigned int idx;
-      bool any_changes = optimize_range_tests (ERROR_MARK, &ops);
-      for (bb = last_bb, idx = 0; any_changes; bb = single_pred (bb), idx++)
-	{
-	  if (bbinfo[idx].first_idx < bbinfo[idx].last_idx)
+      /* update_ops relies on has_single_use predicates returning the
+	 same values as it did during get_ops earlier.  Additionally it
+	 never removes statements, only adds new ones and it should walk
+	 from the single imm use and check the predicate already before
+	 making those changes.
+	 On the other side, the handling of GIMPLE_COND directly can turn
+	 previously multiply used SSA_NAMEs into single use SSA_NAMEs, so
+	 it needs to be done in a separate loop afterwards.  */
+      for (bb = last_bb, idx = 0; ; bb = single_pred (bb), idx++)
+	{
+	  if (bbinfo[idx].first_idx < bbinfo[idx].last_idx
+	      && bbinfo[idx].op != NULL_TREE)
 	    {
-	      gimple stmt = last_stmt (bb);
 	      tree new_op;
 
-	      if (bbinfo[idx].op == NULL_TREE)
-		{
-		  if (ops[bbinfo[idx].first_idx]->op != NULL_TREE)
-		    {
-		      if (integer_zerop (ops[bbinfo[idx].first_idx]->op))
-			gimple_cond_make_false (stmt);
-		      else if (integer_onep (ops[bbinfo[idx].first_idx]->op))
-			gimple_cond_make_true (stmt);
-		      else
-			{
-			  gimple_cond_set_code (stmt, NE_EXPR);
-			  gimple_cond_set_lhs (stmt,
-					       ops[bbinfo[idx].first_idx]->op);
-			  gimple_cond_set_rhs (stmt, boolean_false_node);
-			}
-		      update_stmt (stmt);
-		    }
-		  bbinfo[idx].op = new_op = boolean_false_node;
-		}
-	      else
+	      stmt = last_stmt (bb);
 	      new_op = update_ops (bbinfo[idx].op,
 				   (enum tree_code)
 				   ops[bbinfo[idx].first_idx]->rank,
@@ -2956,6 +2947,28 @@ maybe_optimize_range_tests (gimple stmt)
 	  if (bb == first_bb)
 	    break;
 	}
+      for (bb = last_bb, idx = 0; ; bb = single_pred (bb), idx++)
+	{
+	  if (bbinfo[idx].first_idx < bbinfo[idx].last_idx
+	      && bbinfo[idx].op == NULL_TREE
+	      && ops[bbinfo[idx].first_idx]->op != NULL_TREE)
+	    {
+	      stmt = last_stmt (bb);
+	      if (integer_zerop (ops[bbinfo[idx].first_idx]->op))
+		gimple_cond_make_false (stmt);
+	      else if (integer_onep (ops[bbinfo[idx].first_idx]->op))
+		gimple_cond_make_true (stmt);
+	      else
+		{
+		  gimple_cond_set_code (stmt, NE_EXPR);
+		  gimple_cond_set_lhs (stmt, ops[bbinfo[idx].first_idx]->op);
+		  gimple_cond_set_rhs (stmt, boolean_false_node);
+		}
+	      update_stmt (stmt);
+	    }
+	  if (bb == first_bb)
+	    break;
+	}
     }
   bbinfo.release ();
   ops.release ();