re PR tree-optimization/43186 (A loop in tree_unroll_loops_completely never ends)

2010-02-26  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/43186
	* gimple.h (gimple_fold): Remove.
	* gimple.c (gimple_fold): Remove.  Inline into single user ...
	* tree-cfgcleanup.c (cleanup_control_expr_graph): ... here.
	Try harder for conditions.

	* gcc.c-torture/compile/pr43186.c: New testcase.

From-SVN: r157093

gcc/ChangeLog

+2010-02-26  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/43186
+	* gimple.h (gimple_fold): Remove.
+	* gimple.c (gimple_fold): Remove.  Inline into single user ...
+	* tree-cfgcleanup.c (cleanup_control_expr_graph): ... here.
+	Try harder for conditions.
+
 2010-02-26  Jakub Jelinek  <jakub@redhat.com>
 
 	PR debug/43190

gcc/gimple.c

@@ -1835,54 +1835,6 @@ gimple_set_bb (gimple stmt, basic_block bb)
 }
 
 
-/* Fold the expression computed by STMT.  If the expression can be
-   folded, return the folded result, otherwise return NULL.  STMT is
-   not modified.  */
-
-tree
-gimple_fold (const_gimple stmt)
-{
-  location_t loc = gimple_location (stmt);
-  switch (gimple_code (stmt))
-    {
-    case GIMPLE_COND:
-      return fold_binary_loc (loc, gimple_cond_code (stmt),
-			  boolean_type_node,
-			  gimple_cond_lhs (stmt),
-			  gimple_cond_rhs (stmt));
-
-    case GIMPLE_ASSIGN:
-      switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)))
-	{
-	case GIMPLE_UNARY_RHS:
-	  return fold_unary_loc (loc, gimple_assign_rhs_code (stmt),
-			     TREE_TYPE (gimple_assign_lhs (stmt)),
-			     gimple_assign_rhs1 (stmt));
-	case GIMPLE_BINARY_RHS:
-	  return fold_binary_loc (loc, gimple_assign_rhs_code (stmt),
-			      TREE_TYPE (gimple_assign_lhs (stmt)),
-			      gimple_assign_rhs1 (stmt),
-			      gimple_assign_rhs2 (stmt));
-	case GIMPLE_SINGLE_RHS:
-	  return fold (gimple_assign_rhs1 (stmt));
-	default:;
-	}
-      break;
-
-    case GIMPLE_SWITCH:
-      return gimple_switch_index (stmt);
-
-    case GIMPLE_CALL:
-      return NULL_TREE;
-
-    default:
-      break;
-    }
-
-  gcc_unreachable ();
-}
-
-
 /* Modify the RHS of the assignment pointed-to by GSI using the
    operands in the expression tree EXPR.
 

gcc/gimple.h

@@ -841,7 +841,6 @@ bool gimple_assign_ssa_name_copy_p (gimple);
 bool gimple_assign_single_p (gimple);
 bool gimple_assign_unary_nop_p (gimple);
 void gimple_set_bb (gimple, struct basic_block_def *);
-tree gimple_fold (const_gimple);
 void gimple_assign_set_rhs_from_tree (gimple_stmt_iterator *, tree);
 void gimple_assign_set_rhs_with_ops (gimple_stmt_iterator *, enum tree_code,
 				     tree, tree);

gcc/testsuite/ChangeLog

+2010-02-26  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/43186
+	* gcc.c-torture/compile/pr43186.c: New testcase.
+
 2010-02-26  Jakub Jelinek  <jakub@redhat.com>
 
 	PR debug/43190

gcc/testsuite/gcc.c-torture/compile/pr43186.c

+int n;
+
+void foo (int i)
+{
+  int a, b;
+
+  if (!i)
+    for (a = 1; a < 3; a++)
+      if (a)
+	for (b = 1; b < 3; b++)
+	  foo (b);
+
+  n++;
+}
+

gcc/tree-cfgcleanup.c

@@ -90,9 +90,47 @@ cleanup_control_expr_graph (basic_block bb, gimple_stmt_iterator gsi)
       edge e;
       edge_iterator ei;
       bool warned;
+      location_t loc;
 
       fold_defer_overflow_warnings ();
-      val = gimple_fold (stmt);
+      loc = gimple_location (stmt);
+      switch (gimple_code (stmt))
+	{
+	case GIMPLE_COND:
+	  {
+	    tree lhs = gimple_cond_lhs (stmt);
+	    tree rhs = gimple_cond_rhs (stmt);
+	    /* For conditions try harder and lookup single-argument
+	       PHI nodes.  Only do so from the same basic-block though
+	       as other basic-blocks may be dead already.  */
+	    if (TREE_CODE (lhs) == SSA_NAME)
+	      {
+		gimple def_stmt = SSA_NAME_DEF_STMT (lhs);
+		if (gimple_code (def_stmt) == GIMPLE_PHI
+		    && gimple_phi_num_args (def_stmt) == 1
+		    && gimple_bb (def_stmt) == gimple_bb (stmt))
+		  lhs = PHI_ARG_DEF (def_stmt, 0);
+	      }
+	    if (TREE_CODE (rhs) == SSA_NAME)
+	      {
+		gimple def_stmt = SSA_NAME_DEF_STMT (rhs);
+		if (gimple_code (def_stmt) == GIMPLE_PHI
+		    && gimple_phi_num_args (def_stmt) == 1
+		    && gimple_bb (def_stmt) == gimple_bb (stmt))
+		  rhs = PHI_ARG_DEF (def_stmt, 0);
+	      }
+	    val = fold_binary_loc (loc, gimple_cond_code (stmt),
+				   boolean_type_node, lhs, rhs);
+	    break;
+	  }
+
+	case GIMPLE_SWITCH:
+	  val = gimple_switch_index (stmt);
+	  break;
+
+	default:
+	  val = NULL_TREE;
+	}
       taken_edge = find_taken_edge (bb, val);
       if (!taken_edge)
 	{